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How much warmer on Earth in 2100, compared to mid-19th century?

1-2 degrees
4 (4%)
2-3 degrees
13 (12.9%)
3-4 degrees
24 (23.8%)
4-5 degrees
27 (26.7%)
5-6 degrees
9 (8.9%)
6-10 degrees
16 (15.8%)
10-20 degrees
0 (0%)
20-50 degrees
0 (0%)
50-100 degrees
0 (0%)
Not enough information
8 (7.9%)

Total Members Voted: 90

Author Topic: Magnitude of future warming  (Read 14121 times)


  • Young ice
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Re: Magnitude of future warming
« Reply #150 on: June 18, 2020, 03:49:37 PM »
If I read this right and my numbers are correct, CO2 went up 3.50 ppm May 2018 to May 2019, but only 2.27 ppm May 2019 to May 2020.
Could this reduction in increase (not a decrease) be a result of the shutdown?


  • Grease ice
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Re: Magnitude of future warming
« Reply #151 on: June 18, 2020, 05:06:26 PM »
I'm not sure if this is the most recent time Tamino has looked at it, but 2.5 years ago he concluded:
Bottom line: CO2 is on the rise, the rise itself (velocity) has been getting faster (acceleration), and there’s no evidence at all that has changed recently.

I can't imagine there's enough data since then to definitively concluded that this has changed.


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Re: Magnitude of future warming
« Reply #152 on: June 19, 2020, 01:42:49 AM »
Care to prove the keeling curve is now linear?
Or is that just your eyeballs?

I'm following Wolfpack's and Stephan's analyses of the CO2 at Mauna Loa, trying to detrend, and scrub the data from ENSO variability.

We clearly SEEM to have a slowdown in growth rate, and are almost on constant growth now.,2983.msg268712.html#msg268712

I have previously made a forecast somewhere on this forum that we will reach peak CO2 already by 2030. I still think it's possible due to the very strong growth of renewables. And certainly helped by corona lockdowns.
I expect to see a fall in the CO2 growth rate within a year.


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Re: Magnitude of future warming
« Reply #153 on: June 19, 2020, 08:20:25 AM »

2) The data set you get to play with goes from 1950 - 2020. Over that time frame the CO2 and CH4 effects are only present on the end of the range but not in a way they are detectable in your chosen metrics.

You say that "the CO2 and CH4 effects are only present on the end of the range" /from 1950 - 2020/. You must be joking!
CO2 increases continously during this period of 70 years, and GMST have a strong positive trend, with some hiatuses. This should be reflected in the humidity levels, as the effect of increasing CO2 is supposed to go hand in hand with an increase in water vapour/humidity:

This is what they say at SkS:
"As water vapour is directly related to temperature, it's also a positive feedback - in fact, the largest positive feedback in the climate system (Soden 2005). As temperature rises, evaporation increases and more water vapour accumulates in the atmosphere. As a greenhouse gas, the water absorbs more heat, further warming the air and causing more evaporation. When CO2 is added to the atmosphere, as a greenhouse gas it has a warming effect. This causes more water to evaporate and warm the air to a higher, stabilized level. So the warming from CO2 has an amplified effect"

But the data shows no increase of water vapour, measured as specific humidity (or measured as relative humidity) in the LT. Only a small increase of specific humidity at the surface. (There is btw a bunch of interesting comments at SkS as well, e.g. #2 by someone called Victor.)

The research by Seidel and Yang that cloud feedback in the tropics is negative is also troubling, as clouds are the carriers of water vapour.


  • Guest
Re: Magnitude of future warming
« Reply #154 on: June 19, 2020, 08:52:54 AM »
One could look towards data we believe is reasonably accurate rather than relying on that we know is not.

Radiosonds have their problems, but since 1980 or so satellite data is presumably used.
We have the AQUA satellite with its Atmospheric Infrared Sounder (AIRS), and the Aura satellite, e.g.

According to NASA research, the satellite data shows less of an increase in humidity in the stratosphere, than models assume:
"Models that include water vapor feedback with constant relative humidity predict the Earth's surface will warm nearly twice as much over the next 100 years as models that contain no water vapor feedback.
Using the UARS /satellite/ data to actually quantify both specific humidity and relative humidity, the researchers found, while water vapor does increase with temperature in the upper troposphere, the feedback effect is not as strong as models have predicted. "The increases in water vapor with warmer temperatures are not large enough to maintain a constant relative humidity,""

This is what is shown in the charts in my post above.,2715.msg268929.html#msg268929
Relative humidity is consistently down on all altitudes measured.
« Last Edit: June 19, 2020, 08:59:16 AM by Hefaistos »