For every 1 degree C we increase the temperature on the planet we see 7% more moisture in the atmosphere. We are heading to and beyond the IPCC worst case scenario of 6C minimum which will generate another 40% of moisture in the air. This will lead to a greater number of flooding events and increased number of lightning strikes and Tornadoes.
This is an enormous amount of energy and associated warming as water vapour is in itself a green house gas.

“The impact of climate change may be worse than previously thought, a new study suggests”: “As world leaders hold climate talks in Paris, research shows that land surface temperatures may rise by an average of almost 8C by 2100, if significant efforts are not made to counteract climate change.”
Personally I disagree with the suggestion that it will take until the magic 2100 for our locked in 8C temperature rise. Factor in the myriad of feedback loops and we could be there in a few decades,not that humans will survive that long to bare witness.
Such a rise would have a devastating impact on life on Earth: ‘Climate Outlook May be Worse than Feared.’
“The amount of water vapor in the atmosphere exists in direct relation to the temperature. If you increase the temperature, more water evaporates and becomes vapor, and vice versa. So when something else causes a temperature increase (such as extra CO2 from fossil fuels), more water evaporates. Then, since water vapor is a green house gas, this additional water vapor causes the temperature to go up even further—a positive feedback.”
Explaining how the Water Vapor Greenhouse effect works; Sceptical Science.
How much does water vapor amplify CO2 warming? Studies show that water vapor feed back roughly doubles the amount of warming caused by CO2. So if there is a 1°C change caused by CO2, the water vapor will cause the temperature to go up another 1°C. When other feedback loops are included, the total warming from a potential 1°C change caused by CO2 is, in reality, as much as 3°C.
“A warmer atmosphere can hold more moisture, and globally water vapour increases by 7% for every degree centigrade of warming.”
Excellent article and Q & A from The Guardian in the following link: ‘How Will Climate Change Affect Rainfall?‘
Editing this new information into the blog from Sam Carana 06/09/2024
“How much more water vapor currently is in the atmosphere compared to pre-industrial depends on how much the temperature has risen since pre-industrial. The February 2024 temperature was 1.76°C above 1885-1915, which could be as much as 2.75°C above the pre-industrial temperature. A 2.75°C rise corresponds with almost ⅕ more water vapor in the atmosphere.”
Water Vapor Feedback
Update 28th of January 2025:
Whilst this latest analysis of the interaction between the hydrological cycle and nitrogen runoff from land to creeks, rivers and eventually oceans, is based on a peer reviewed study in the Gulf of Mexico it is equally applicable in Aotearoa New Zealand.
The full script of this analysis and hyperlinks to the sources can be found at Professor McPherson’s Substack post titled Science Snippets: How Climate Change Causes a Polluted Gulf of Mexico
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Is that 7per percent rise linear? Or are there some diminishing returns?
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Ouch!!!!!
https://www.zmescience.com/science/news-science/scientists-simulate-the-runaway-greenhouse-process-that-could-make-earth-unhabitable/
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Ouch, another feedback loop!
https://www.science.org/doi/10.1126/science.adf5041?fbclid=IwAR2778_FUHMml3VtC6ZzX6_Xspdb7RLaY9XUorqj-TivjUQNG0WKT7ny-lA
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[…] water vapour for every 1C we broil the planet. In mountainous regions it can be as much as 15%! Each 1 Degree C We Warm the Planet adds an additional 7% Increase in Moisture into the Atmosphere.“On this episode, Nate is joined by climate researcher Leon Simons to unpack recent trends in […]
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Atmospheric rivers are driving crazy climate extremes in Antarctica (youtube.com)
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Planet Will Warm as Much as 3.1C Under Current Policies: UN Report
https://www.ecowatch.com/unep-emissions-gap-report-2024-climate-crisis.html
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There should be a disclaimer here because they left out ‘At First.’ Since Dr. Hansen’s team came out with the 10’C number a while ago, this number seems to be more of a hopium guess than anything else. Especially since the article included a ‘this century’ which I think is absolutely ridiculous with there being no concerted effort by any government to cut emissions since the corporations that fund the politicians aren’t about to lose profits.
But the UN is trying not to scare anybody, keep the status quo going, calm the masses. And no rocking of boats allowed because a worldwide panic might ensue.
Ya think that might be bad for business?
Big sigh.
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Selkirk Range weather:
Below freezing at night ranging to 5-10C daytime with an occasional freak day going to 20C+. That high is getting less common as November is here in two days… I’ve noticed that every time a rain shower comes through these last couple of weeks the temp goes UP. A bit unusual for these mountains this time of year.
Zero snow with nothing showing on the peaks nearby last I looked. Local low-elevation ski hill hasn’t even seen a dusting yet, nor have they started up their ‘snowmaking’ machines because the icy chunks that blow out of them will melt in these temperatures.
Bears are still being spotted around here. Late hibernation it looks like, too.
I’m still pulling in firewood which is kicking my back into pain levels I haven’t had since last Fall doing the same thing. This gets harder every year…
But if this fourth La Nina winter in a row does what the last three have done, it’ll snow really hard for one big storm, a meter or so, in late Dec or early Jan. Last Winter Solstice there was none on the valley floor below me right up to 9Jan when it dropped 1.3 meters over 24 hours, and then start fucking raining. Practically nothing after that except in little snow spurts until the heat starts up again. I had zero snow on the ground by early March when it used to be dumping white over these last 20 years.
Big sigh. I am living Global Warming, dude. It sucks.
Hope all is well with you, Kev.
sealintheSelkirks
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Science Snippets: Atmospheric Rivers Warming Winters, Driving Heatwaves
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Arctic news
Sam Carana ·
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Group expert
Deforestation can cause eight-fold increase in flood event risk, says report https://www.unsw.edu.au/…/Deforestation-eight-fold…
Interception reduction from deforestation and forest fire increases large-scale fluvial flooding risk – by Tae-Ho Kang et al. https://www.nature.com/articles/s43247-025-02748-6
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How the Water Vapour Feedback loop can transform terrain
https://www.youtube.com/watch?v=KNZxDBG4k_Y
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Vietnam city sets national record with 1.7 m rain in 24 hours
Hanoi (AFP) – The central Vietnamese city of Hue recorded more than a metre of rain in a 24-hour period, smashing a national record set over two decades ago, the environment ministry said Tuesday.
Vietnam city sets national record with 1.7 m rain in 24 hours
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Jamaica just experienced 40″ of rain in less than 12 hours from Cat 5 Hurricane Melissa with a windspeed of 185mph. If it would have stalled and lasted 24 hours it might have surpassed what Vietnam had.
It sure smashed flat Jamaica, though. Shredded towns and farms and tore roofs off everywhere, building collapses all over, and that one town in the mountains where the eye passed over with 250mph winds pretty much doesn’t really exist any longer. The steep mountains of that island flash-flooded everything, too, torrents of water washing everything towards the sea… The strongest hurricane on record Jamaica has ever experienced.
The next day the temperature was right back up in the sweltering 80s as it strengthened and slammed into Cuba as a Cat 2.
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Worldwide, dude. Everywhere is getting hit and we know it’s only going to get much, much worse.
sealintheSelkirks
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