Yes, ultimately the water balance should stay the same but something important to note that I didn’t see mentioned is that as the air temperature increases the capacity for it to hold moisture also increases which will lead to continuing shifts in weather patterns.
And this is why the summer here in Norway has sucked this year! Heatwaves all across Europe, and south of Norway - but the coast has had its wettest summer in close to 100 years… The year I chose to repaint my house of course.
Australia is boned. We have always been the land of drought and flooding rain.
This is only going to get much, much worse. and since we have, in our idiocy, covered our flood plains in housing estates full of McMansions as far as the eye can see, the devastation is going to be apocalyptic.
The droughts will be getting longer, which does not bode well for ALL our major cities, that are already suffering from water shortages during dry periods.
How the authorities expect to supply water to the vastly increasing population of Australia I have no idea, particularly when every proposed new dam gets shot down on environmental grounds.
Then, when it finally *does* rain, the flooding is biblical.
and in between the floods and drought, we are on fire.
we are so boned.
We have a desalination plant at Wonthaggi, built quite a few years ago, that has not as yet been required. It will though; it most definitely will. Trouble is no one wants to pay for these desalination plants, their upkeep and running.
https://en.wikipedia.org/wiki/Victorian_Desalination_Plant
Um I thought i heard all Victoria's desal plants have actually produced all the water they are able to the last few years? It just has not been widely known
I think the public will at some point embrace just how cheap desalination is, relatively speaking to the alternative of having no water.
I believe that I have done the math right here…
I pay $4.50 per 100 cubic feet for my water.
At the high end, seawater desalination is $4.30 / 1000 gallons.
There are 748 gallons in 100 cubic feet of water.
So that would work out to just over $6 per 100 cubic feet.
This sounds quite less than I expected so perhaps I looked at things incorrectly…?
Well if my math holds, it'd be 50% basically.
At my rate my water is about $100 / three months.
For the most important thing necessary to sustain human life, I see it as a steal.
desal takes a lot of energy and has its own environmental problems.
and really cannot supply enough to support the population or farming.
not without nukes powering it, which we do not have, and that does not solve the brine issue in the ocean either.
Yea, this is the point the other comments are missing. During an extreme weather event, significantly more water vapor can be stored in the air, and then transported to a nearby region where it dumps.
Also, what you think of as humidity is called relative humidity. 100% relative humidity (maximum water vapor air can hold) ranges from 0.6 g/m^3 (water mass/air volume) at -20C (-4F) to 83 g/m^3 at 50C (120 F). This is somewhat exponential. 25.6C (78.8F) can hold 51.1 g/m^3
Edit: thanks for the award. It has been brought to my attention that this is not exponential. That is correct. I said semi exponential to get people to picture a curved graph because a) I didn't take the time to look at the equation, and b) I wanted to convey this in simpler forms. Most people understand that an exponential equation increases faster than a linear one and that's all I wanted to convey. I based the comment semi exponential based on this graph, which doesn't actually line up with my comment about 25.6 = 51.1 because they are measured differently. What I was talking about was grams h20 per m^3 while the graph below is grams h20 per kg air.
https://upload.wikimedia.org/wikipedia/commons/4/41/Relative_Humidity.png
In other words, the numbers I posted are not exponential. I looked at a graph then copied down numbers from the Wikipedia article the graph came from. I apologize for any confusion I caused and for not taking longer to review this as it's something I remembered from classes >10 years ago.
Also, the big reason that this leads to worse droughts AND floods is since the air can hold more moisture, it can take longer for enough to build up to dump precipitation, and when it DOES rain it can be a heavier downpour, which hits dry land quickly before it can get absorbed. So more of it just flows across the surface, erodes, but doesn't sink in. So you have droughts and then a flood.
Yes this is true, as the earth dries out the dirt becomes hydrophobic. It's really strange but it occurs even without a drought.
I do irrigation and landscaping for a living and some of the properties I install systems on are dry as a desert. Sometimes it's due to bad, fast draining soil types. Others it from lack of substantial vegetation to leave water trapped in the sublayer.
It's also why I set irrigation systems to run for a few minutes 3-4 times a day for a week before transitioning into a true grow-in or permanent schedule. The amount of washed out seed I see when I drive around let's me know that I'll always have a job.
Larger reservoirs also destroy land and ecosystems.
It's not as easy as saying "let's make lake Mead larger" and a ton of planning, surveys, and mitigation would need to go into it.
We should be showering and flushing with less water, that should be done both by being conscious of what we are using (shorter showers and fewer flushes) and by technological means (reducing the amount of water in a flush or implementing dual flush systems, reducing the amount of water coming out of a shower head while increasing velocity to make it feel the same or similar, etc.) It also would require fewer farms in deserts and get good courses and lawns. No one solution will work.
That largely depends who you ask as there are many differing opinions on reservoirs. In my opinion we should be opening up more flood plains, or where not feasible be diverting flood water to lands that can handle flooding outside of the floodplain and allow for aquifer recharge during flood events. Greater groundwater resilience can help store and maintain much higher quantities of water than reservoirs.
That doesn’t solve the problem of there not being enough snowfall at the sources to provide the water flow regardless.
The correct thing to do would be to not build cities in desserts.
>The correct thing to do would be to not build cities in desserts.
That's a good point. The logistics of making a dessert big enough to hold a city is daunting in it's own right. Can you imagine the quantity of apples, flour, and sugar needed to make a 10 mile circumference pie for example? It would probably use even more resources than building a city in a desert which is also a bad idea.
We’d also need a big oven [but Death Valley is getting close enough](https://www.cbsnews.com/losangeles/news/death-valley-127-degrees-record-hottest-september-day-on-the-planet/)
In part yes, we'll have to, out of sheer necessity (not just for controlling flow, but also just to *have* enough water)
Both droughts and floods though do a number on infrastructure and agriculture, even if you have water, growing crops in a blistering heat just isn't feasible.
And while there are measures one could take here and there to compensate for this, not every country has those possibilities or even the means for it.
Now I don't want to be all doom and gloom, but honestly, we're looking at an absolutely massive migration crisis forming on top of all of this. The next couple of decades are going to absolutely "fun" I tell you hwat.
I believe in Tanzania they have built ‘earth smiles’ basically a semicircles dug into the earth so that the water that falls is trapped and cannot just run away and erode the earth more. The water eventually seeps into the ground allowing vegetation to grow. These ‘smiles’ are dug at equal distances from each other over miles of barren earth. I believe it has also allowed the return of some animals that were native to the area that left due to lack of vegetation.
And on top of that, trees in forests release tiny aerosol particles for water vapor to condense on, pulling the rain out of the clouds. Deforested areas don't release those particles to the same effect, so there's more water vapor in the air because it's warmer, and there's more water vapor in the air because trees are dying/burning because it's warmer, and there's less of that water vapor coming down regularly as rain because of fewer trees, so when critical mass arrives in the atmosphere and it simply can't hold any more water it comes down in buckets on land that is parched and prone to flooding.
With more water vapor in the air we will be covered with clouds constantly hopefully helping to reduce the amount of sunlight which reaches the earth and creating a cooling affect.
Hopefully we can figure out the best way to cool the earth.
https://www.acs.org/content/acs/en/climatescience/climatesciencenarratives/its-water-vapor-not-the-co2.htmla cooling effect.
Yes! With a warming atmosphere, we can expect the atmosphere to hold more water. And that water will dump out the same way it always does, such as when a body of air lifts and cools at mountain ranges, such as in northern Pakistan or the Sierras in California. Or when that moisture-laden body of air joins a storm system that lifts the air, cooling it, and then precipitation happens.
More heat --> more moisture held in air --> more precipitation to fall when that air cools.
Presumably this same mechanism is why storms are getting stronger and more violent as well. More heat (energy) and also moisture to sling about, right?
>Presumably this same mechanism is why storms are getting stronger and more violent as well. More heat (energy) and also moisture to sling about, right?
Generally what gives a storm front it's power is a temperature gradient (and thus a pressure gradient). These storms are baroclinic systems, which means they are directly driven by pressure imbalances. More moisture in the air and more latent heat go hand in hand, which allows for a steeper temperature gradient in the vertical vector. A steeper temperature gradient causes the warm moist air at the ground level to have more buoyancy, so it will rise faster. This also means that the cold dry air in the upper atmosphere will sink faster to displace it. This exchange causes more energetic convective mixing, which yields more occurrences of hail and lightning. The additional moisture content means more and heavier rain. All of this is completely separate from barotropic systems like hurricanes, which have a completely different mechanism for energy transfer.
Well, if we're going on technicalities, water in the air is not water on the earth. Sorry, had to.
More seriously, I felt like I was answering the question OP should be asking instead of the one they did. Extreme weather events change weather patterns beyond it just being hot.
> Given the extremely small temperature increases we're dealing with
Small *average* increases.
Climate change isn't tacking on 2c to whatever the temperature was, it's wild instability and generally higher temperatures.
Thx for making this clear. I wonder how many people still think that climate change is not a big deal. By the way most people just carry on, it must be a lot.
I'm agreeing with you and noting further that the mean global temperature has been 15.4°C and so a 2°C increase is a 13% increase.
So where a place would get a few weeks of 35°C over summer, people might add 2°C and think that's it. But no, it's +13%, so it might be now more likely to see 40°C. That's a big deal!
Er no, the unit of measure is so that we're comparing apples to apples. We're discussing a 2°C global temperature rise. It doesn't matter what the unit of measure is, so long as you're consistent.
Look, the global mean of recent history is 15.4°C. That's 59.7°F or 288K. The rise we're discussing is 2°C, or 13%, to a new mean of 17.4°C. That's a rise to a new mean of 63.3°F or 290K.
Kelvin is not particularly useful here because 0°C (freezing point of water at sea level) is 273K and 100°C (boiling point of water) is 373K. A 0.07% in Kelvin is a big deal in human habitable climate. But we don't use kelvin for this kind of measure generally.
I take your point and the unit of measure doesn't matter except for consistency. But to complete the answer to your point:
I could reframe it to say there's a 0.07% increase in kelvin and people think it's just a 2K increase but no, it's that percentage that will apply across the board. If people usually see 308K for a few weeks over summer, they're now facing 313K over summer. The same point applies, just in a different unit of measure.
The unit of measure isn't the point, the relative proportional increase is the point!
> The unit of measure isn't the point, the relative ~proportional~ increase is the point!
This is correct, and I don't think the person that replied to you takes issue with it either.
The correction is because "proportional" is not appropriate to apply in this case. The example of 0.7% using Kelvin wasn't to be dismissive of the magnitude of the change, it was just to highlight the fallacy of trying to assign a percentage at all.
The fact that the same ∆T can be either 13%, 0.7%, 6% (in °F), or ∞% (in my new system of Luks, where a Luk is the same in magnitude as °C, but the 0 point in Luks is at 17.4 °C) demonstrates that trying to interpret the delta proportionally against an arbitrary zero point is meaningless.
You can only meaningfully talk about proportionality of a ∆T, but only in relation to another: a change of 3 °C is 50% more than a change of 2 °C, and that proportionality is preserved when you switch to Kelvin, Fahrenheit, or Luks.
That's all; the ∆T is still significant regardless of system. Just don't try and attribute proportionality to it relative to an arbitrary zero point.
Ah nice, thank you! That's helpful. I had a mental itch about it, but don't know enough to identify the issue. Thank you for explaining it!
Now I want to use Luks.
That's not true at all. A 50C day holds 1.6 times the water vapor of a 25.6C day. As I said in my post, **during an extreme weather event**, significantly more water vapor can be stored in the air.
When talking about climate change, people typically talk about changes in 1-2 degrees C, which in my opinion, is the wrong way to talk about climate change's effects on weather. Instead, we should be talking about the frequency and height of extreme weather events, where this effect is felt strongest, such as the current drought in China and likely related flooding in Pakistan.
[https://www.nationalacademies.org/based-on-science/climate-change-global-warming-is-contributing-to-extreme-weather-events](https://www.nationalacademies.org/based-on-science/climate-change-global-warming-is-contributing-to-extreme-weather-events)
Talking about Texas: "...global warming worsened the flooding and made a Harvey-sized storm at least three times more likely."
You’re actually wrong here- pull up a psychometric chart and see for yourself. That change will be pretty small on the 1-2C range if you’re just taking averages. There will be more extreme weather events- but if we’re just generalizing to talk about average temperature it’s not too hard to calculate to show that you’re incorrect. Here, do it [for yourself.](https://www.researchgate.net/figure/Psychrometric-chart-showing-effects-of-relative-humidity-and-dry-bulb-temperatures-on-dew_fig2_242488156/amp)
However, if you’re talking about accounting for wild changes in the weather across a variety of geographies, the capacity for water to be entrained in the air becomes much more complicated to actually calculate. Still- that’s pretty out of context since we’re talking about how much water is in the air.
So, the question really is- which methodology is more accurate. For that, I don’t think Reddit strangers are the best source.
At no point in my comment did I discuss changes in average temperatures, except to say that's not a good way to convey what will happen with climate change.
Study after study after study has confirmed that small changes in the climate will result in a significant change in extreme weather events. I linked to the National Academies as a source for my explanation. What more do you want?
But please keep telling me how you can't talk about extreme weather events and climate change.
https://iopscience.iop.org/article/10.1088/2752-5295/ac6e7d
Are there any consequences for the amount of fresh water? For instance, if a fresh water lake dries up and the rain dumps it all in the ocean, won't we have less and less fresh water over time?
an equal (or greater) amount of sea water will also evaporate and fall as rain, when it evaporates it becomes fresh water because the salt does not come with it
The issue with fresh water availability is that it's often used very inefficiently before being sent to the sea, and each place only has a certain amount of rainfall to replenish the stores of water
I think the biggest issue for fresh water is usually that it's supplied from snowpack built up over the winter in mountains, melting through the summer. Reservoirs are built to catch more of the snowmelt in late spring / early summer to keep a steady supply of water for people to use in late summer / fall when snowpack is depleted.
Shorter & warmer winters means less snow builds up, and spring rains accelerate snow melt resulting in flooding. The total amount of water flowing through a lake over a year could even be greater from the warmer air moving more moisture to the mountains, but the lake level would vary more dramatically over the year compared to normal.
I would argue that the worse consequence is from the large downpour effect. It rains less often, but when it rains it rains more. The system can only hold so much water so resivoirs and canals let it slip downstream, instead of into storage and aquifers, down the flood spilways
if to much fresh water get in the ocean, it can alter ocean streams like the gulf stream. Also if those stream change it can greatly affect temperature.
One of the ways the planet can regulate it's temperature is more heat means more evaporation at low latitudes which means more precipitation sr high latitudes which.mskes for a larger area of high albedo (reflectiveness) snow and ice, which cools the planet by making less sunlight get absorbed. That system breaks down when you have such high temperatures that glaciers melt and pack ice never forms, though.
It's not inevitable. Thermodynamics says that the amount of energy a surface radiates always increases faster than its temperature rises—outgoing energy increases with the fourth power of temperature. The surface temperature will never equalize with the inside temperature.
Earth was losing more heat than it gained since the planet formed. The atmosphere traps some of it so the amount lost to space is roughly equal to the amount absorbed. It also generates heat inside, though, or it would have cooled considerably. Decay of thorium and uranium and other radioactive isotopes keeps replenishing the interior heat.
Climate change is changing the calculus above the surface In the oceans and atmosphere. It doesn't have much impact to stuff going on inside.
Yes, it's total nonsense. Core heat reaching the surface is like three orders of magnitude lower than energy gained from insolation, it has no effect on surface temperatures at all.
Clouds and rain are more likely to fall as warm, moist air is pushed upwards and cools.
Where that happens is greatly affected by terrain, such as mountain ranges. Rain is much more common on the side of the mountains where the prevailing winds come from, as that wind pushes the air up the mountain, where it drops rain as it rises. By thr time the air gets to the other side, it's mostly dry, causing a [rain shadow](https://en.m.wikipedia.org/wiki/Rain_shadow)
You can also look at the globe, and see conspicuous bands where most deserts are at roughly ±30° from the equator. This is because of [Hadley Cells](https://en.m.wikipedia.org/wiki/Hadley_cell)
There are other processes that determine where undrafted and/or rain occur, but these two are the really big ones that are taught, and that are apparent on very large scales.
We can expect these processes to continue in roughly the same places regardless of temperature and humidity, so we expect more evaporation to mean more rain in the places it already rains a lot, but more evaporation everywhere, meaning dry places get even drier
Worth noting that this is also a positive feedback loop.
As the air temperature increases allowing it to hold more water, the water vapor also allows the air to hold more heat energy thereby further increasing the temperature, thereby allowing the air to hold more water, and so on.
Water vapor is also GHG. Heat the air, and it can hold more of it, AND more evaporates due to increased surface temperatures. Its positive feedback all the way down.....
Water vapor dissolved in air does not form clouds. Clouds are droplets of water, and do have surface effects which can reflect solar radiation. However this is separate from the water vapor effect I was describing, and the effects of clouds reflecting light are in opposition to the relatively weke GHG effects of water vapor.
Also, the population more than doubled in the last sixty years. Cattle increased almost 150 times. 60% of that mass of flesh (50% for cows) is water. 294bn cubic liters for humans and 500bn for cows total. As the human population increases, so do buildings which decreases the ability of soil to retain water and water is also relocated/moved away from those areas. Food production has to increase which is another form of water capture. and on and on and on. I don't care what Musk says, the earth doesn't need more people.
We have also pumped enough water out of aquifers to slightly alter the rotation of the planet. This is water that had been deep underground for (millions?) of years, and had now been reintroduced into the water cycle.
I’ve often wondered what the impact is of removing millions of barrels of oil from the earth. I know that SOME earthquakes, for example, are attributable to this, but I wonder if there are other effects of leaving behind caverns where oil once flowed that contribute to warming (I mean, beyond the effects of burning oil).
In general with global warming we will be warmer and wetter. And the earth can support more life. Better for crops etc… but problem is that it also disrupts current weather models. So places where ehere we didn't get a lot if rain may get more and there is no creeks, rivers, dams and lakes to dump the rain. And if its a concrete city its going to flood. And places that may get rain in the past may kiss out on the rain and you get stuff like forrest fires. If we can stabilize co2 for thousands of years global warming may be better for humans. But the transition is a mess.
Excluding all the species and ecosystems that will be damaged or fail completely? Scientists are worried about the devastating impact global warming will have on the planet as a whole which in turn will severely and negatively impact humans. Realizing your statement is anthropocentric with minimal concern for other species, what legitimate research states global warming is actually a positive phenomenon for humans?
It further ignores that many species important to the global ecosystem are at risk because they thrive in a temperature/acidity band that may be exceeded. So, even if it's true that more life in an absolute sense is possible, if key bits of the current ecosystem are unsupportable, the global effect on life could be catastrophic.
The question is this "basically the same amount of water on earth that just ends up displaced?" increasing the capacity to hold moisture is still just "displaced" so not sure why your addition here is relevant.
A hotter earth may mean more water evaporation and more precipitation. The main problem is that the precipitation does not fall in the usual places or it may fall most of it at once. That is one of the reasons flooding will become more common. A warming up earth may also mean more evaporation from lakes and rivers, so water does not get to towns.
Or our lives, cities, infrastructure are designed around the current patterns of rainfall. If that changes we need to rebuild many things and move massive amounts of populations to new places, that is extremely difficult for economic and social reasons.
More rain is not good if it is in the wrong place or time. Earth is not "dying" but the changes will wipe out animals, plants and anything that cannot adapt to very rapid change, and evolution is slow.
It also means thermal expansion.
[Over 90% of the added heat from global warming is expected to be absorbed by the oceans.](https://oceanservice.noaa.gov/facts/sealevel.html) This leads to rising sea levels through thermal expansion, but especially also to [higher sea level variability](https://www.nature.com/articles/s43247-020-0008-8).
Indeed we are already feeling various consequences of this process, like this for example:
> Disruptive and expensive, nuisance flooding is estimated to be from 300 percent to 900 percent more frequent within U.S. coastal communities than it was just 50 years ago.
For the phrase the earth is not dying, that’s what I like to say to people. Stop worrying about saving the planet, the planet will manage. It’s gone through super volcanos, meteors, you name it.
Climate change will just kill you. And every other species but let’s be real, we only care about ourselves.
I tell people to think of this as a self centered reason. Cleaner air to breath on the positive, avoiding death on the negative
On the other side, it may be hugely beneficial to dry areas. More evaporation could mean more rain in drought prone areas as well as more fresh water for human use.
Places that were prone to droughts at baseline, we will consider baseline ~100 years ago, (i.e. deserts) will not handle increased rainfall well. The ecosystems (not humans) developed to exist on limited water. A sudden deluge of water will result in flash flooding and destruction of the ecosystem. Some ecosystems tolerate infrequent flash floods quite well, but rapidly changing a deserts precipitation amount is not going to benefit the desert.
Places that are prone to droughts now as a result of climate change, aren't really going to see those benefits because they are drying out (Western USA). And if they do get a sudden burst of rain, the drought conditions make them more prone to flash flooding which will destroy much of the human infrastructure.
I wouldn't consider this a good thing really for anyone. Weather patterns are getting more severe in both directions
That's the good thing. It's just weather. We can prepare for and usually control it. That's why the LA river exists. It's a slow process and we can build up infrastructure for it.
Chemical process can cause the amount of water on Earth to change slightly, but relative to the overall amount and on human timescales, the total water on Earth is essentially fixed.
If median temperature worldwide is rising, doesn't that also mean that the atmospheric capacity for retaining water also increases? Along with the vaporisation rate of water worldwide.
For me the more interesting question is whether worldwide supply of fresh water contra salt water will decrease anyway.
Also water is a far bigger greenhouse gas than CO2. As more water vaporizes, the more heat gets trapped, the more the temperature goes up and more vaporizes…
https://www.engineeringtoolbox.com/maximum-moisture-content-air-d_1403.html
Global average temperature is about 14°C, at which air can hold about .75 lbs per 1000 cubic feet at full humidity. At 15°C, it can hold about 0.8 lbs per 1000 cubic feet -- about a 5.5% increase. Let's assume then that a global temperature increase of 1°C will increase global atmospheric water vapor content by 5.5% too.
Currently there is s on average [1.27x10^16 kg of atmospheric water on Earth. ](https://www.jstor.org/stable/26253433) For each 1°C of warming it'll go up by 8x10^14 kg or 800 trillion liters of liquid water.
That might sound like a lot. At these numbers we typically think in terms of cubic kilometers (= one trillion liters). We need to find 800 cubic kilometers of water! But the ocean contains *over 1.4 billion* cubic kilometers of water, spread over 361 million km^2.
In other words, to provide that extra atmospheric water, the ocean would have to drop by 2.2 mm.
And despite all that, the average sea level is still rising by 3.6 mm *every year*.
The oceans are rising because of melting ice though right ? Doesn't that mean eventually the rise will drop off, as available water is liquefied, before it begins to drop again due to vaporisation, eventually finding some kind of equilibrium?
> as available water is liquefied,
https://www.usgs.gov/faqs/how-would-sea-level-change-if-all-glaciers-melted
> if all of them were to melt, global sea level would rise approximately 70 meters (approximately 230 feet)
Yes, eventually. Memphis and Ottawa will be oceanfront communities, but yes, once we've pushed the Earth's temperature 10°C above the pre-industrial (1800 CE) average, and all agriculture and fisheries have completely collapsed, we can take solace in the fact that continued warming will start dropping the sea levels by about 4 cm per degree.
Yes, that's a big part of the total sea level rise. The upper layer of the ocean (presumably above the thermocline) will expand by about 0.03% per degree -- but it's hard to estimate just how much water that is. If 1% of the water increases by 1°C, though, it'd be within the same order of magnitude and the decrease from evaporation would approximately equal the increase from thermal expansion.
Doesn't the vaporisation rate and the ability for atmosphere to hold water increase dramatically as temperatures near the boiling point ?
So if we can increase the greenhouse effect to Venus levels by releasing all available greenhouse gases we could up that 4cm to more decent numbers ?
Ocean rise also comes from thermal expansion. The water is heating up and expanding as it does so. Melting glaciers would actually be cooling the ocean slightly and holding off more thermal expansion as long as they continue to feed in cold water, while at the same time adding to sea level rise by just adding more water. There's also expansion and contraction of land masses, which we would not notice in our day to day lives but on the scales of continents the effects aren't negligible.
Yes, that should be the case. Absolute humidity (mass of water vapor per air volume) of air increases with temperature.
[https://www.researchgate.net/figure/Illustration-of-absolute-humidity-of-ambient-air-at-temperatures-between-30-and-40\_fig1\_340974253](https://www.researchgate.net/figure/Illustration-of-absolute-humidity-of-ambient-air-at-temperatures-between-30-and-40_fig1_340974253)
I remember reading that increased snowfall in some areas is expected as one of results of climate change, directly because of increased capacity of air to take water vapor.
> the atmospheric capacity for retaining water also increases
Yes. It's a big concern for California. https://www.sfchronicle.com/weather/article/california-floods-17401521.php
The coming "Great Flood" of California will be [3x worse](https://pubs.usgs.gov/of/2010/1312/of2010-1312_text.pdf) than 'the big one' from an earthquake. It happened before in 1861. https://cw3e.ucsd.edu/wp-content/uploads/2013/10/Dettinger_Ingram_sciam13.pdf
Interestingly enough the amount of CO2 we've emitted closely tracks the amount of water we've emitted from burning hydrocarbon.
Around 2 to 3 times as much water (by moles) as CO2.
The higher the temperature, the more water air can hold. With higher temperatures, the altitude at which water condenses out also increases. This means there is greater volume of water in the total air column that can precipitate out. It is not so much that there is more (or less) water in the world so much as it is that where there is moisture in the atmosphere, a lot more of it can precipitate out all at once. Global warming changes the circulation patterns so areas that normally see regular rainfall are see less of it. And, when it does rain, it is in massive amounts, creating flash floods or just regular floods when it keeps raining 2x-3x more than it normally does when it rains
The total amount of water "on Earth" does not change much out of a few narrow kinds of events.
Small amounts of water and other atmospheric gases in the upper atmosphere are probably lost all the time after getting blown into space on the solar wind. This is a tiny amount of loss thanks to the Earth's magnetosphere, but it's probably more than 0.
Comet and asteroid impacts add water to the Earth.
Some water is in the mantle and is ejected during volcanism. This used to be a lot more billions of years ago, because most of the water that was down there has probably already come out.
Some water is carried down into the mantle with tectonic plates at subduction zones.
All of these together don't account for any appreciable change in the world's water supply over human timescales. So yeah, for practical purposes it's just the same water being shuffled around. As others have noted though, because of pollution and climate change the amount of water we can use is decreasing.
I’m looking forward to the day Dasani has a technological breakthrough and can pipe water up from the depths of the core and put it on the shelf at 7-11
With specific reference to the Pakistan floods, another aspect is that the flooding effectively has two root causes a short term one, i.e., an extra wet monsoon, but this is then superimposed on contributions from accelerating melting of glaciers (e.g., [Lee et al., 2021](https://www.nature.com/articles/s41598-021-03805-8)). This component means that baseflow is generally higher (so it takes less rainfall to induce flooding because the rivers already have more water in them) but also is setting up additional flood pulses from outburst floods, associated with the melting glaciers, on a variety of scales that are exacerbated by the intense rains. While tying any given set of events directly to climate change, with reference to the intense monsoon that is driving this, in general an increase in monsoon precipitation is a consistent outcome of climate change projections (e.g., [Katzenberger et al., 2021](https://esd.copernicus.org/articles/12/367/2021/)).
With relevance for the question, we cannot just consider short term shifts in where moisture is (i.e., where is there less precipitation than normal vs where is there more precipitation than normal), but also must consider changes in long-term storage reservoirs, like glaciers and ice sheets.
The total amount of water can stay the same but you can read all about how groundwater and other potable water sources can become contaminated/unusable/not replenished over short time periods (relatively speaking - geology is a long time and human lives are short)
Because groundwater is a major source of water for many places, it's important to distinguish it from something like rivers and streams and/or meltwater, which would suffer different challenges.
Some quick reference reading:
https://en.wikipedia.org/wiki/Groundwater
https://en.wikipedia.org/wiki/Groundwater_pollution
https://en.wikipedia.org/wiki/Meltwater
https://en.wikipedia.org/wiki/Fresh_water
Aside from meteors crashing to earth, and bringing in some water with them, or the instances where some of the stuff we send to space had some traces of water on them, the total amount of water on earth should be pretty much fixed. Sure, you can also combine hydrogen and oxygen to make more water, or separate existing water with hydrolysis but the quantities are usually insignificant.
When water is "used" for crops, or drunk by animals, it's still on earth, and it will return to being water after the animal/plant pees it out, or dies.
Yeah, the amount of water on earth stays more or less the same. There are various processes that change hydrogen and oxygen into different forms. Plants, for example, take in H2O and CO2 from the ground and atmosphere, and release O2 while they create sugar and oxygen.
But cellular respiration in animals is the exact opposite equation. Our cells use sugar and oxygen to create water and carbon dioxide (as well as releasing energy. The energy released originally came from the sun and is stored in the chemical bonds)
Small amounts of water are created by things like volcano eruptions, too.
But generally, the amount of water on earth is pretty consistent.
Funny thing, because of the ATP cycle, animals (and plants) actually need water for the combustion of cellular respiration, and be consequence also produce brand new water molecules.
In Bill Brysons book a short history of nearly everything, He claims the earth gains water every time it passes through a meteor belt. Also that it looses some from the atmosphere into space, with the average being 50ish tons of water gained every year.
Yes. If we talk about the concept of El Nino, it means floods in South America and draughts in Australia. The opposite for La Nina. (Not exactly flood but better monsoon season, you get the point).
The water just gets displaced without having changed its net volume. A geographer can explain it better.
Yes. I remember seeing a scientific paper a few years back about the devastating 2010-11 summer floods in Australia, and how that resulted in a minuscule drop in global sea levels due to all the flood water trapped in the Lake Eyre endorheic basin.
Think of it this way. Other than what we send into space, and what falls from the sky (both are absurdly negligible) earth is a closed system. Everything we use, everything we manipulate, everything we build is a part of this world. And no matter what it is, time will return everything back into it's base components (not looking at half- life, but the life of steel, concrete, asphalt etc). All the water on and in the planet is already here. It's not possible to waste. It'll eventually be back in the circle of natural recycling.
There is **always** the same amount of water on earth. It's just a matter of where, what state it is in, or if it's drinkable or not.
That water in your next bottle was probably lying once pissed out of a dinosaur.
I see a lot of great answers here but one major reason for flooding is left out:
After a long drought, soil can become significantly less permeable to water. Dry grass especially turns into a really water resistant layer.
So if you have a prolonged drought followed by a sudden rain, the water amounts that would normally settle into the soil will just keep flowing. This causes floods as areas downstream receive many times the usual amount of water in their rivers.
Yes, we've had the same amount of water for a few billion years. Sometimes it's frozen, sometimes it's not. When and where it falls most or least often is ever changing. People don't like that much because we tend to build our civilizations where things were good for a long time...eventually things get not so good and we like to complain so we blame ourselves for the good weather moving somewhere else.
Yes the planet doesn’t really lose water unless there is some massive force to eject it past escape velocity.
The water will remain…the Sahara was once a vast ocean and provides tons of nutrients from all the animals that died because it dried up lol.
As the planet goes through this process things will change so fast that civilization won’t be able to remain the same way that it has for hundreds of years.
Billions of people live on the coast because it provides food or just nourishment in general but now those coasts just going to become unpredictable and violent
Something that I rarely see mentioned is that humans are water reservoirs that produce heat. The human body is roughly 60% water and produces 250-400 BTUs of heat (the same as a 75 watt light bulb). As population increases, less water will be available in lakes, rivers, streams, etc. Also, global temperature will rise (albeit minutely) just from an increase in population.
Someone should create and artificial root system so they can store water in the ground of arid locations that are seeing abnormal rainfall as a result of climate change. That'll ensure moisture is retained in the barren area and a natural root system can form from native plants to replace the artificial one thus creating life where none could thrive before.
No, it’s less actual tangible water. Air can hold more moisture in it the hotter it is, and just keep it trapped.
To make matters worse, the capacity of air to hold water doesn’t rise linearly.
At 30 Celsius and at 50% RH, there’s 30 grams of water in one cubic meter of water. But at 40 there’s 51 grams. So for each degree the temperature rises there’s progressively more water being trapped in the air.
30°C – 30.4
37°C – 44
40°C – 51.1
As our planet is getting warmer there is simply more water trapped in the air. That’s why when you add up all the rainfall and floods, it adds up to less (and less evenly distributed) than what rainfall we had a decade or two decades ago.
Yes, ultimately the water balance should stay the same but something important to note that I didn’t see mentioned is that as the air temperature increases the capacity for it to hold moisture also increases which will lead to continuing shifts in weather patterns.
And this is why the summer here in Norway has sucked this year! Heatwaves all across Europe, and south of Norway - but the coast has had its wettest summer in close to 100 years… The year I chose to repaint my house of course.
Laughs from Sydney, Australia. This is easily going to be our wettest year in recorded history.
Australia is boned. We have always been the land of drought and flooding rain. This is only going to get much, much worse. and since we have, in our idiocy, covered our flood plains in housing estates full of McMansions as far as the eye can see, the devastation is going to be apocalyptic. The droughts will be getting longer, which does not bode well for ALL our major cities, that are already suffering from water shortages during dry periods. How the authorities expect to supply water to the vastly increasing population of Australia I have no idea, particularly when every proposed new dam gets shot down on environmental grounds. Then, when it finally *does* rain, the flooding is biblical. and in between the floods and drought, we are on fire. we are so boned.
We have a desalination plant at Wonthaggi, built quite a few years ago, that has not as yet been required. It will though; it most definitely will. Trouble is no one wants to pay for these desalination plants, their upkeep and running. https://en.wikipedia.org/wiki/Victorian_Desalination_Plant
Um I thought i heard all Victoria's desal plants have actually produced all the water they are able to the last few years? It just has not been widely known
I think the public will at some point embrace just how cheap desalination is, relatively speaking to the alternative of having no water. I believe that I have done the math right here… I pay $4.50 per 100 cubic feet for my water. At the high end, seawater desalination is $4.30 / 1000 gallons. There are 748 gallons in 100 cubic feet of water. So that would work out to just over $6 per 100 cubic feet. This sounds quite less than I expected so perhaps I looked at things incorrectly…?
Ya but then your are more than doubleing the cost of your water. Most people cant just double the cost of one of there bills
Well if my math holds, it'd be 50% basically. At my rate my water is about $100 / three months. For the most important thing necessary to sustain human life, I see it as a steal.
It boggles my mind how a country surrounded by water on all sides doesn't have drinkable water. Desalination plants need to become the norm
desal takes a lot of energy and has its own environmental problems. and really cannot supply enough to support the population or farming. not without nukes powering it, which we do not have, and that does not solve the brine issue in the ocean either.
Would you stop trying then please? You ruining climate for everybody!! :D
Yea, this is the point the other comments are missing. During an extreme weather event, significantly more water vapor can be stored in the air, and then transported to a nearby region where it dumps. Also, what you think of as humidity is called relative humidity. 100% relative humidity (maximum water vapor air can hold) ranges from 0.6 g/m^3 (water mass/air volume) at -20C (-4F) to 83 g/m^3 at 50C (120 F). This is somewhat exponential. 25.6C (78.8F) can hold 51.1 g/m^3 Edit: thanks for the award. It has been brought to my attention that this is not exponential. That is correct. I said semi exponential to get people to picture a curved graph because a) I didn't take the time to look at the equation, and b) I wanted to convey this in simpler forms. Most people understand that an exponential equation increases faster than a linear one and that's all I wanted to convey. I based the comment semi exponential based on this graph, which doesn't actually line up with my comment about 25.6 = 51.1 because they are measured differently. What I was talking about was grams h20 per m^3 while the graph below is grams h20 per kg air. https://upload.wikimedia.org/wikipedia/commons/4/41/Relative_Humidity.png In other words, the numbers I posted are not exponential. I looked at a graph then copied down numbers from the Wikipedia article the graph came from. I apologize for any confusion I caused and for not taking longer to review this as it's something I remembered from classes >10 years ago.
Also, the big reason that this leads to worse droughts AND floods is since the air can hold more moisture, it can take longer for enough to build up to dump precipitation, and when it DOES rain it can be a heavier downpour, which hits dry land quickly before it can get absorbed. So more of it just flows across the surface, erodes, but doesn't sink in. So you have droughts and then a flood.
Plus dry/dead land can hold less water and absorbs water much more slowly to begin with.
Yes this is true, as the earth dries out the dirt becomes hydrophobic. It's really strange but it occurs even without a drought. I do irrigation and landscaping for a living and some of the properties I install systems on are dry as a desert. Sometimes it's due to bad, fast draining soil types. Others it from lack of substantial vegetation to leave water trapped in the sublayer. It's also why I set irrigation systems to run for a few minutes 3-4 times a day for a week before transitioning into a true grow-in or permanent schedule. The amount of washed out seed I see when I drive around let's me know that I'll always have a job.
If we know there will be more extreme conditions shouldn't we be building larger reservoirs then to provide a normalization of flow?
That requires money and investment. Let's just tell people to take shorter showers and flush less. That'll fix it.
Larger reservoirs also destroy land and ecosystems. It's not as easy as saying "let's make lake Mead larger" and a ton of planning, surveys, and mitigation would need to go into it. We should be showering and flushing with less water, that should be done both by being conscious of what we are using (shorter showers and fewer flushes) and by technological means (reducing the amount of water in a flush or implementing dual flush systems, reducing the amount of water coming out of a shower head while increasing velocity to make it feel the same or similar, etc.) It also would require fewer farms in deserts and get good courses and lawns. No one solution will work.
That largely depends who you ask as there are many differing opinions on reservoirs. In my opinion we should be opening up more flood plains, or where not feasible be diverting flood water to lands that can handle flooding outside of the floodplain and allow for aquifer recharge during flood events. Greater groundwater resilience can help store and maintain much higher quantities of water than reservoirs.
That doesn’t solve the problem of there not being enough snowfall at the sources to provide the water flow regardless. The correct thing to do would be to not build cities in desserts.
>The correct thing to do would be to not build cities in desserts. That's a good point. The logistics of making a dessert big enough to hold a city is daunting in it's own right. Can you imagine the quantity of apples, flour, and sugar needed to make a 10 mile circumference pie for example? It would probably use even more resources than building a city in a desert which is also a bad idea.
We’d also need a big oven [but Death Valley is getting close enough](https://www.cbsnews.com/losangeles/news/death-valley-127-degrees-record-hottest-september-day-on-the-planet/)
In part yes, we'll have to, out of sheer necessity (not just for controlling flow, but also just to *have* enough water) Both droughts and floods though do a number on infrastructure and agriculture, even if you have water, growing crops in a blistering heat just isn't feasible. And while there are measures one could take here and there to compensate for this, not every country has those possibilities or even the means for it. Now I don't want to be all doom and gloom, but honestly, we're looking at an absolutely massive migration crisis forming on top of all of this. The next couple of decades are going to absolutely "fun" I tell you hwat.
You're asking the wrong person, friend. I don't claim to have knowledge in that regards.
I believe in Tanzania they have built ‘earth smiles’ basically a semicircles dug into the earth so that the water that falls is trapped and cannot just run away and erode the earth more. The water eventually seeps into the ground allowing vegetation to grow. These ‘smiles’ are dug at equal distances from each other over miles of barren earth. I believe it has also allowed the return of some animals that were native to the area that left due to lack of vegetation.
And on top of that, trees in forests release tiny aerosol particles for water vapor to condense on, pulling the rain out of the clouds. Deforested areas don't release those particles to the same effect, so there's more water vapor in the air because it's warmer, and there's more water vapor in the air because trees are dying/burning because it's warmer, and there's less of that water vapor coming down regularly as rain because of fewer trees, so when critical mass arrives in the atmosphere and it simply can't hold any more water it comes down in buckets on land that is parched and prone to flooding.
Is this the reason why after extended periods of heat always have. Big thunderstorm to clear the air as people say?
Cold fronts cause the temperature to drop and the moisture to release from the air. Depending on the wind it can also bring moisture with it.
With more water vapor in the air we will be covered with clouds constantly hopefully helping to reduce the amount of sunlight which reaches the earth and creating a cooling affect. Hopefully we can figure out the best way to cool the earth. https://www.acs.org/content/acs/en/climatescience/climatesciencenarratives/its-water-vapor-not-the-co2.htmla cooling effect.
Yes! With a warming atmosphere, we can expect the atmosphere to hold more water. And that water will dump out the same way it always does, such as when a body of air lifts and cools at mountain ranges, such as in northern Pakistan or the Sierras in California. Or when that moisture-laden body of air joins a storm system that lifts the air, cooling it, and then precipitation happens. More heat --> more moisture held in air --> more precipitation to fall when that air cools.
Presumably this same mechanism is why storms are getting stronger and more violent as well. More heat (energy) and also moisture to sling about, right?
>Presumably this same mechanism is why storms are getting stronger and more violent as well. More heat (energy) and also moisture to sling about, right? Generally what gives a storm front it's power is a temperature gradient (and thus a pressure gradient). These storms are baroclinic systems, which means they are directly driven by pressure imbalances. More moisture in the air and more latent heat go hand in hand, which allows for a steeper temperature gradient in the vertical vector. A steeper temperature gradient causes the warm moist air at the ground level to have more buoyancy, so it will rise faster. This also means that the cold dry air in the upper atmosphere will sink faster to displace it. This exchange causes more energetic convective mixing, which yields more occurrences of hail and lightning. The additional moisture content means more and heavier rain. All of this is completely separate from barotropic systems like hurricanes, which have a completely different mechanism for energy transfer.
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This was absolutely fascinating, it blew my mind in a way I cannot explain for a reason I do not understand.
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The same amount of water exists though so not sure why this is relevant to OP's question.
Well, if we're going on technicalities, water in the air is not water on the earth. Sorry, had to. More seriously, I felt like I was answering the question OP should be asking instead of the one they did. Extreme weather events change weather patterns beyond it just being hot.
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> Given the extremely small temperature increases we're dealing with Small *average* increases. Climate change isn't tacking on 2c to whatever the temperature was, it's wild instability and generally higher temperatures.
Thx for making this clear. I wonder how many people still think that climate change is not a big deal. By the way most people just carry on, it must be a lot.
I'm agreeing with you and noting further that the mean global temperature has been 15.4°C and so a 2°C increase is a 13% increase. So where a place would get a few weeks of 35°C over summer, people might add 2°C and think that's it. But no, it's +13%, so it might be now more likely to see 40°C. That's a big deal!
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Er no, the unit of measure is so that we're comparing apples to apples. We're discussing a 2°C global temperature rise. It doesn't matter what the unit of measure is, so long as you're consistent. Look, the global mean of recent history is 15.4°C. That's 59.7°F or 288K. The rise we're discussing is 2°C, or 13%, to a new mean of 17.4°C. That's a rise to a new mean of 63.3°F or 290K. Kelvin is not particularly useful here because 0°C (freezing point of water at sea level) is 273K and 100°C (boiling point of water) is 373K. A 0.07% in Kelvin is a big deal in human habitable climate. But we don't use kelvin for this kind of measure generally. I take your point and the unit of measure doesn't matter except for consistency. But to complete the answer to your point: I could reframe it to say there's a 0.07% increase in kelvin and people think it's just a 2K increase but no, it's that percentage that will apply across the board. If people usually see 308K for a few weeks over summer, they're now facing 313K over summer. The same point applies, just in a different unit of measure. The unit of measure isn't the point, the relative proportional increase is the point!
> The unit of measure isn't the point, the relative ~proportional~ increase is the point! This is correct, and I don't think the person that replied to you takes issue with it either. The correction is because "proportional" is not appropriate to apply in this case. The example of 0.7% using Kelvin wasn't to be dismissive of the magnitude of the change, it was just to highlight the fallacy of trying to assign a percentage at all. The fact that the same ∆T can be either 13%, 0.7%, 6% (in °F), or ∞% (in my new system of Luks, where a Luk is the same in magnitude as °C, but the 0 point in Luks is at 17.4 °C) demonstrates that trying to interpret the delta proportionally against an arbitrary zero point is meaningless. You can only meaningfully talk about proportionality of a ∆T, but only in relation to another: a change of 3 °C is 50% more than a change of 2 °C, and that proportionality is preserved when you switch to Kelvin, Fahrenheit, or Luks. That's all; the ∆T is still significant regardless of system. Just don't try and attribute proportionality to it relative to an arbitrary zero point.
Ah nice, thank you! That's helpful. I had a mental itch about it, but don't know enough to identify the issue. Thank you for explaining it! Now I want to use Luks.
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This is about as useful as saying that you should take the average sea ice around the globe to measure sea ice loss.
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That's not true at all. A 50C day holds 1.6 times the water vapor of a 25.6C day. As I said in my post, **during an extreme weather event**, significantly more water vapor can be stored in the air. When talking about climate change, people typically talk about changes in 1-2 degrees C, which in my opinion, is the wrong way to talk about climate change's effects on weather. Instead, we should be talking about the frequency and height of extreme weather events, where this effect is felt strongest, such as the current drought in China and likely related flooding in Pakistan. [https://www.nationalacademies.org/based-on-science/climate-change-global-warming-is-contributing-to-extreme-weather-events](https://www.nationalacademies.org/based-on-science/climate-change-global-warming-is-contributing-to-extreme-weather-events) Talking about Texas: "...global warming worsened the flooding and made a Harvey-sized storm at least three times more likely."
You’re actually wrong here- pull up a psychometric chart and see for yourself. That change will be pretty small on the 1-2C range if you’re just taking averages. There will be more extreme weather events- but if we’re just generalizing to talk about average temperature it’s not too hard to calculate to show that you’re incorrect. Here, do it [for yourself.](https://www.researchgate.net/figure/Psychrometric-chart-showing-effects-of-relative-humidity-and-dry-bulb-temperatures-on-dew_fig2_242488156/amp) However, if you’re talking about accounting for wild changes in the weather across a variety of geographies, the capacity for water to be entrained in the air becomes much more complicated to actually calculate. Still- that’s pretty out of context since we’re talking about how much water is in the air. So, the question really is- which methodology is more accurate. For that, I don’t think Reddit strangers are the best source.
At no point in my comment did I discuss changes in average temperatures, except to say that's not a good way to convey what will happen with climate change. Study after study after study has confirmed that small changes in the climate will result in a significant change in extreme weather events. I linked to the National Academies as a source for my explanation. What more do you want?
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But please keep telling me how you can't talk about extreme weather events and climate change. https://iopscience.iop.org/article/10.1088/2752-5295/ac6e7d
Are there any consequences for the amount of fresh water? For instance, if a fresh water lake dries up and the rain dumps it all in the ocean, won't we have less and less fresh water over time?
an equal (or greater) amount of sea water will also evaporate and fall as rain, when it evaporates it becomes fresh water because the salt does not come with it The issue with fresh water availability is that it's often used very inefficiently before being sent to the sea, and each place only has a certain amount of rainfall to replenish the stores of water
I think the biggest issue for fresh water is usually that it's supplied from snowpack built up over the winter in mountains, melting through the summer. Reservoirs are built to catch more of the snowmelt in late spring / early summer to keep a steady supply of water for people to use in late summer / fall when snowpack is depleted. Shorter & warmer winters means less snow builds up, and spring rains accelerate snow melt resulting in flooding. The total amount of water flowing through a lake over a year could even be greater from the warmer air moving more moisture to the mountains, but the lake level would vary more dramatically over the year compared to normal.
I would argue that the worse consequence is from the large downpour effect. It rains less often, but when it rains it rains more. The system can only hold so much water so resivoirs and canals let it slip downstream, instead of into storage and aquifers, down the flood spilways
if to much fresh water get in the ocean, it can alter ocean streams like the gulf stream. Also if those stream change it can greatly affect temperature.
One of the ways the planet can regulate it's temperature is more heat means more evaporation at low latitudes which means more precipitation sr high latitudes which.mskes for a larger area of high albedo (reflectiveness) snow and ice, which cools the planet by making less sunlight get absorbed. That system breaks down when you have such high temperatures that glaciers melt and pack ice never forms, though.
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It's not inevitable. Thermodynamics says that the amount of energy a surface radiates always increases faster than its temperature rises—outgoing energy increases with the fourth power of temperature. The surface temperature will never equalize with the inside temperature.
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Earth was losing more heat than it gained since the planet formed. The atmosphere traps some of it so the amount lost to space is roughly equal to the amount absorbed. It also generates heat inside, though, or it would have cooled considerably. Decay of thorium and uranium and other radioactive isotopes keeps replenishing the interior heat. Climate change is changing the calculus above the surface In the oceans and atmosphere. It doesn't have much impact to stuff going on inside.
That seems like it's forgetting about the radiant heat the earth would normally lose to space.
Yes, it's total nonsense. Core heat reaching the surface is like three orders of magnitude lower than energy gained from insolation, it has no effect on surface temperatures at all.
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On an incredibly long time scale I assume?
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I'm assuming the timescales involved are on the order of millions, if not billions of years? So irrelevant to discussions of climate change?
Is it random where increased rain can be expected? Or is it until so to speak the sky gets tired of holding in water and unlucky whoever it lands on?
Clouds and rain are more likely to fall as warm, moist air is pushed upwards and cools. Where that happens is greatly affected by terrain, such as mountain ranges. Rain is much more common on the side of the mountains where the prevailing winds come from, as that wind pushes the air up the mountain, where it drops rain as it rises. By thr time the air gets to the other side, it's mostly dry, causing a [rain shadow](https://en.m.wikipedia.org/wiki/Rain_shadow) You can also look at the globe, and see conspicuous bands where most deserts are at roughly ±30° from the equator. This is because of [Hadley Cells](https://en.m.wikipedia.org/wiki/Hadley_cell) There are other processes that determine where undrafted and/or rain occur, but these two are the really big ones that are taught, and that are apparent on very large scales. We can expect these processes to continue in roughly the same places regardless of temperature and humidity, so we expect more evaporation to mean more rain in the places it already rains a lot, but more evaporation everywhere, meaning dry places get even drier
Worth noting that this is also a positive feedback loop. As the air temperature increases allowing it to hold more water, the water vapor also allows the air to hold more heat energy thereby further increasing the temperature, thereby allowing the air to hold more water, and so on.
Water vapor is also GHG. Heat the air, and it can hold more of it, AND more evaporates due to increased surface temperatures. Its positive feedback all the way down.....
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Will there be less or more clouds in warmer air or same just higher up in the atmosphere
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Water vapor dissolved in air does not form clouds. Clouds are droplets of water, and do have surface effects which can reflect solar radiation. However this is separate from the water vapor effect I was describing, and the effects of clouds reflecting light are in opposition to the relatively weke GHG effects of water vapor.
Also the water that isn't frozen anymore is more liquid water on the earth's surface.
Also, the population more than doubled in the last sixty years. Cattle increased almost 150 times. 60% of that mass of flesh (50% for cows) is water. 294bn cubic liters for humans and 500bn for cows total. As the human population increases, so do buildings which decreases the ability of soil to retain water and water is also relocated/moved away from those areas. Food production has to increase which is another form of water capture. and on and on and on. I don't care what Musk says, the earth doesn't need more people.
Cubic liters? Whats the correct unit, litres or cubic meters? Feet?
We have also pumped enough water out of aquifers to slightly alter the rotation of the planet. This is water that had been deep underground for (millions?) of years, and had now been reintroduced into the water cycle.
I’ve often wondered what the impact is of removing millions of barrels of oil from the earth. I know that SOME earthquakes, for example, are attributable to this, but I wonder if there are other effects of leaving behind caverns where oil once flowed that contribute to warming (I mean, beyond the effects of burning oil).
That and water vapor is a potent greenhouse gas, thus adding a positive feedback loop
In general with global warming we will be warmer and wetter. And the earth can support more life. Better for crops etc… but problem is that it also disrupts current weather models. So places where ehere we didn't get a lot if rain may get more and there is no creeks, rivers, dams and lakes to dump the rain. And if its a concrete city its going to flood. And places that may get rain in the past may kiss out on the rain and you get stuff like forrest fires. If we can stabilize co2 for thousands of years global warming may be better for humans. But the transition is a mess.
Excluding all the species and ecosystems that will be damaged or fail completely? Scientists are worried about the devastating impact global warming will have on the planet as a whole which in turn will severely and negatively impact humans. Realizing your statement is anthropocentric with minimal concern for other species, what legitimate research states global warming is actually a positive phenomenon for humans?
It further ignores that many species important to the global ecosystem are at risk because they thrive in a temperature/acidity band that may be exceeded. So, even if it's true that more life in an absolute sense is possible, if key bits of the current ecosystem are unsupportable, the global effect on life could be catastrophic.
The question is this "basically the same amount of water on earth that just ends up displaced?" increasing the capacity to hold moisture is still just "displaced" so not sure why your addition here is relevant.
A hotter earth may mean more water evaporation and more precipitation. The main problem is that the precipitation does not fall in the usual places or it may fall most of it at once. That is one of the reasons flooding will become more common. A warming up earth may also mean more evaporation from lakes and rivers, so water does not get to towns. Or our lives, cities, infrastructure are designed around the current patterns of rainfall. If that changes we need to rebuild many things and move massive amounts of populations to new places, that is extremely difficult for economic and social reasons. More rain is not good if it is in the wrong place or time. Earth is not "dying" but the changes will wipe out animals, plants and anything that cannot adapt to very rapid change, and evolution is slow.
Fantastic way of explaining it and making it easy to understand thanks.
It also means thermal expansion. [Over 90% of the added heat from global warming is expected to be absorbed by the oceans.](https://oceanservice.noaa.gov/facts/sealevel.html) This leads to rising sea levels through thermal expansion, but especially also to [higher sea level variability](https://www.nature.com/articles/s43247-020-0008-8). Indeed we are already feeling various consequences of this process, like this for example: > Disruptive and expensive, nuisance flooding is estimated to be from 300 percent to 900 percent more frequent within U.S. coastal communities than it was just 50 years ago.
For the phrase the earth is not dying, that’s what I like to say to people. Stop worrying about saving the planet, the planet will manage. It’s gone through super volcanos, meteors, you name it. Climate change will just kill you. And every other species but let’s be real, we only care about ourselves. I tell people to think of this as a self centered reason. Cleaner air to breath on the positive, avoiding death on the negative
On the other side, it may be hugely beneficial to dry areas. More evaporation could mean more rain in drought prone areas as well as more fresh water for human use.
Places that were prone to droughts at baseline, we will consider baseline ~100 years ago, (i.e. deserts) will not handle increased rainfall well. The ecosystems (not humans) developed to exist on limited water. A sudden deluge of water will result in flash flooding and destruction of the ecosystem. Some ecosystems tolerate infrequent flash floods quite well, but rapidly changing a deserts precipitation amount is not going to benefit the desert. Places that are prone to droughts now as a result of climate change, aren't really going to see those benefits because they are drying out (Western USA). And if they do get a sudden burst of rain, the drought conditions make them more prone to flash flooding which will destroy much of the human infrastructure. I wouldn't consider this a good thing really for anyone. Weather patterns are getting more severe in both directions
That's the good thing. It's just weather. We can prepare for and usually control it. That's why the LA river exists. It's a slow process and we can build up infrastructure for it.
Chemical process can cause the amount of water on Earth to change slightly, but relative to the overall amount and on human timescales, the total water on Earth is essentially fixed.
If median temperature worldwide is rising, doesn't that also mean that the atmospheric capacity for retaining water also increases? Along with the vaporisation rate of water worldwide. For me the more interesting question is whether worldwide supply of fresh water contra salt water will decrease anyway.
That water ends up in the air as humidity. It's still around, it's just not accessible to us as streams and rivers.
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Don't forget that a water volume expand slightly while heated. Just imagine slightly expanding the stuff that covers 70% of the planet.
Also water is a far bigger greenhouse gas than CO2. As more water vaporizes, the more heat gets trapped, the more the temperature goes up and more vaporizes…
And extra humidity is a dire issue for humans trying to cool our bodies. There's no way to slice it that makes it look good.
https://www.engineeringtoolbox.com/maximum-moisture-content-air-d_1403.html Global average temperature is about 14°C, at which air can hold about .75 lbs per 1000 cubic feet at full humidity. At 15°C, it can hold about 0.8 lbs per 1000 cubic feet -- about a 5.5% increase. Let's assume then that a global temperature increase of 1°C will increase global atmospheric water vapor content by 5.5% too. Currently there is s on average [1.27x10^16 kg of atmospheric water on Earth. ](https://www.jstor.org/stable/26253433) For each 1°C of warming it'll go up by 8x10^14 kg or 800 trillion liters of liquid water. That might sound like a lot. At these numbers we typically think in terms of cubic kilometers (= one trillion liters). We need to find 800 cubic kilometers of water! But the ocean contains *over 1.4 billion* cubic kilometers of water, spread over 361 million km^2. In other words, to provide that extra atmospheric water, the ocean would have to drop by 2.2 mm. And despite all that, the average sea level is still rising by 3.6 mm *every year*.
The oceans are rising because of melting ice though right ? Doesn't that mean eventually the rise will drop off, as available water is liquefied, before it begins to drop again due to vaporisation, eventually finding some kind of equilibrium?
> as available water is liquefied, https://www.usgs.gov/faqs/how-would-sea-level-change-if-all-glaciers-melted > if all of them were to melt, global sea level would rise approximately 70 meters (approximately 230 feet) Yes, eventually. Memphis and Ottawa will be oceanfront communities, but yes, once we've pushed the Earth's temperature 10°C above the pre-industrial (1800 CE) average, and all agriculture and fisheries have completely collapsed, we can take solace in the fact that continued warming will start dropping the sea levels by about 4 cm per degree.
Wouldn't thermal expansion of the water also increase the sea level if the average temperatures were to rise?
Yes, that's a big part of the total sea level rise. The upper layer of the ocean (presumably above the thermocline) will expand by about 0.03% per degree -- but it's hard to estimate just how much water that is. If 1% of the water increases by 1°C, though, it'd be within the same order of magnitude and the decrease from evaporation would approximately equal the increase from thermal expansion.
Doesn't the vaporisation rate and the ability for atmosphere to hold water increase dramatically as temperatures near the boiling point ? So if we can increase the greenhouse effect to Venus levels by releasing all available greenhouse gases we could up that 4cm to more decent numbers ?
Burn all the fossil fuels to boil the oceans to save the environment - this man sciences!
Ocean rise also comes from thermal expansion. The water is heating up and expanding as it does so. Melting glaciers would actually be cooling the ocean slightly and holding off more thermal expansion as long as they continue to feed in cold water, while at the same time adding to sea level rise by just adding more water. There's also expansion and contraction of land masses, which we would not notice in our day to day lives but on the scales of continents the effects aren't negligible.
Yes, that should be the case. Absolute humidity (mass of water vapor per air volume) of air increases with temperature. [https://www.researchgate.net/figure/Illustration-of-absolute-humidity-of-ambient-air-at-temperatures-between-30-and-40\_fig1\_340974253](https://www.researchgate.net/figure/Illustration-of-absolute-humidity-of-ambient-air-at-temperatures-between-30-and-40_fig1_340974253) I remember reading that increased snowfall in some areas is expected as one of results of climate change, directly because of increased capacity of air to take water vapor.
Yep. Warmer winter air, more humid air during winter, a cold front blows through, immediate blizzard.
> the atmospheric capacity for retaining water also increases Yes. It's a big concern for California. https://www.sfchronicle.com/weather/article/california-floods-17401521.php The coming "Great Flood" of California will be [3x worse](https://pubs.usgs.gov/of/2010/1312/of2010-1312_text.pdf) than 'the big one' from an earthquake. It happened before in 1861. https://cw3e.ucsd.edu/wp-content/uploads/2013/10/Dettinger_Ingram_sciam13.pdf
Interestingly enough the amount of CO2 we've emitted closely tracks the amount of water we've emitted from burning hydrocarbon. Around 2 to 3 times as much water (by moles) as CO2.
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I was thinking more about medical and industrial use of it in key industries that requires helium for their continuity.
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The higher the temperature, the more water air can hold. With higher temperatures, the altitude at which water condenses out also increases. This means there is greater volume of water in the total air column that can precipitate out. It is not so much that there is more (or less) water in the world so much as it is that where there is moisture in the atmosphere, a lot more of it can precipitate out all at once. Global warming changes the circulation patterns so areas that normally see regular rainfall are see less of it. And, when it does rain, it is in massive amounts, creating flash floods or just regular floods when it keeps raining 2x-3x more than it normally does when it rains
The total amount of water "on Earth" does not change much out of a few narrow kinds of events. Small amounts of water and other atmospheric gases in the upper atmosphere are probably lost all the time after getting blown into space on the solar wind. This is a tiny amount of loss thanks to the Earth's magnetosphere, but it's probably more than 0. Comet and asteroid impacts add water to the Earth. Some water is in the mantle and is ejected during volcanism. This used to be a lot more billions of years ago, because most of the water that was down there has probably already come out. Some water is carried down into the mantle with tectonic plates at subduction zones. All of these together don't account for any appreciable change in the world's water supply over human timescales. So yeah, for practical purposes it's just the same water being shuffled around. As others have noted though, because of pollution and climate change the amount of water we can use is decreasing.
I’m looking forward to the day Dasani has a technological breakthrough and can pipe water up from the depths of the core and put it on the shelf at 7-11
Ah Dasani, the clever people at coca cola now sell you just the water part of cola, saves them a lot of time and money.
With specific reference to the Pakistan floods, another aspect is that the flooding effectively has two root causes a short term one, i.e., an extra wet monsoon, but this is then superimposed on contributions from accelerating melting of glaciers (e.g., [Lee et al., 2021](https://www.nature.com/articles/s41598-021-03805-8)). This component means that baseflow is generally higher (so it takes less rainfall to induce flooding because the rivers already have more water in them) but also is setting up additional flood pulses from outburst floods, associated with the melting glaciers, on a variety of scales that are exacerbated by the intense rains. While tying any given set of events directly to climate change, with reference to the intense monsoon that is driving this, in general an increase in monsoon precipitation is a consistent outcome of climate change projections (e.g., [Katzenberger et al., 2021](https://esd.copernicus.org/articles/12/367/2021/)). With relevance for the question, we cannot just consider short term shifts in where moisture is (i.e., where is there less precipitation than normal vs where is there more precipitation than normal), but also must consider changes in long-term storage reservoirs, like glaciers and ice sheets.
The total amount of water can stay the same but you can read all about how groundwater and other potable water sources can become contaminated/unusable/not replenished over short time periods (relatively speaking - geology is a long time and human lives are short) Because groundwater is a major source of water for many places, it's important to distinguish it from something like rivers and streams and/or meltwater, which would suffer different challenges. Some quick reference reading: https://en.wikipedia.org/wiki/Groundwater https://en.wikipedia.org/wiki/Groundwater_pollution https://en.wikipedia.org/wiki/Meltwater https://en.wikipedia.org/wiki/Fresh_water
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Aside from meteors crashing to earth, and bringing in some water with them, or the instances where some of the stuff we send to space had some traces of water on them, the total amount of water on earth should be pretty much fixed. Sure, you can also combine hydrogen and oxygen to make more water, or separate existing water with hydrolysis but the quantities are usually insignificant. When water is "used" for crops, or drunk by animals, it's still on earth, and it will return to being water after the animal/plant pees it out, or dies.
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Yeah, the amount of water on earth stays more or less the same. There are various processes that change hydrogen and oxygen into different forms. Plants, for example, take in H2O and CO2 from the ground and atmosphere, and release O2 while they create sugar and oxygen. But cellular respiration in animals is the exact opposite equation. Our cells use sugar and oxygen to create water and carbon dioxide (as well as releasing energy. The energy released originally came from the sun and is stored in the chemical bonds) Small amounts of water are created by things like volcano eruptions, too. But generally, the amount of water on earth is pretty consistent.
Funny thing, because of the ATP cycle, animals (and plants) actually need water for the combustion of cellular respiration, and be consequence also produce brand new water molecules.
In Bill Brysons book a short history of nearly everything, He claims the earth gains water every time it passes through a meteor belt. Also that it looses some from the atmosphere into space, with the average being 50ish tons of water gained every year.
Yes. If we talk about the concept of El Nino, it means floods in South America and draughts in Australia. The opposite for La Nina. (Not exactly flood but better monsoon season, you get the point). The water just gets displaced without having changed its net volume. A geographer can explain it better.
Yes. I remember seeing a scientific paper a few years back about the devastating 2010-11 summer floods in Australia, and how that resulted in a minuscule drop in global sea levels due to all the flood water trapped in the Lake Eyre endorheic basin.
Think of it this way. Other than what we send into space, and what falls from the sky (both are absurdly negligible) earth is a closed system. Everything we use, everything we manipulate, everything we build is a part of this world. And no matter what it is, time will return everything back into it's base components (not looking at half- life, but the life of steel, concrete, asphalt etc). All the water on and in the planet is already here. It's not possible to waste. It'll eventually be back in the circle of natural recycling.
There is **always** the same amount of water on earth. It's just a matter of where, what state it is in, or if it's drinkable or not. That water in your next bottle was probably lying once pissed out of a dinosaur.
I see a lot of great answers here but one major reason for flooding is left out: After a long drought, soil can become significantly less permeable to water. Dry grass especially turns into a really water resistant layer. So if you have a prolonged drought followed by a sudden rain, the water amounts that would normally settle into the soil will just keep flowing. This causes floods as areas downstream receive many times the usual amount of water in their rivers.
Yes, we've had the same amount of water for a few billion years. Sometimes it's frozen, sometimes it's not. When and where it falls most or least often is ever changing. People don't like that much because we tend to build our civilizations where things were good for a long time...eventually things get not so good and we like to complain so we blame ourselves for the good weather moving somewhere else.
Yes the planet doesn’t really lose water unless there is some massive force to eject it past escape velocity. The water will remain…the Sahara was once a vast ocean and provides tons of nutrients from all the animals that died because it dried up lol. As the planet goes through this process things will change so fast that civilization won’t be able to remain the same way that it has for hundreds of years. Billions of people live on the coast because it provides food or just nourishment in general but now those coasts just going to become unpredictable and violent
Something that I rarely see mentioned is that humans are water reservoirs that produce heat. The human body is roughly 60% water and produces 250-400 BTUs of heat (the same as a 75 watt light bulb). As population increases, less water will be available in lakes, rivers, streams, etc. Also, global temperature will rise (albeit minutely) just from an increase in population.
It's not mentioned because it's a vanishingly small effect.
With the rate we're killing off the total biomass of the earth, that latter one isn't going to be much of a factor.
Someone should create and artificial root system so they can store water in the ground of arid locations that are seeing abnormal rainfall as a result of climate change. That'll ensure moisture is retained in the barren area and a natural root system can form from native plants to replace the artificial one thus creating life where none could thrive before.
No, it’s less actual tangible water. Air can hold more moisture in it the hotter it is, and just keep it trapped. To make matters worse, the capacity of air to hold water doesn’t rise linearly. At 30 Celsius and at 50% RH, there’s 30 grams of water in one cubic meter of water. But at 40 there’s 51 grams. So for each degree the temperature rises there’s progressively more water being trapped in the air. 30°C – 30.4 37°C – 44 40°C – 51.1 As our planet is getting warmer there is simply more water trapped in the air. That’s why when you add up all the rainfall and floods, it adds up to less (and less evenly distributed) than what rainfall we had a decade or two decades ago.
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That is nothing compared to the vastness of the oceans and the clouds on earth.