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bdgwx

Observational evidence of increasing global radiative forcing

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Some of you probably saw news articles regarding the Kramer et al 2021 publication which for the first time measures the net instantaneous radiative force using CERES and AIRS between 2003 and 2018.

News Article: https://www.ecowatch.com/greenhouse-effect-nasa-study-2651319284.html

Official: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL091585 

Free: https://www.essoar.org/doi/10.1002/essoar.10506610.1

From the publication...

Total-IRF = +0.033 W/m2/year +/- 0.007
LW-IRF = +0.027 W/m2/year +/- 0.006
SW-IRF = +0.006 W/m2/year +/- 0.003

The SOCRATES radiative transfer model predicts LW-IRF to be +0.023 W/m2/year +/- 0.003. The model computes the RF for increases in most of the GHG species found in the atmosphere. Note that measurement and modeling are consistent here.

The MERRA reanalysis attributes +0.006 W/m2/year +/- 0.003 to aerosol declines. Note that this matches well with the measured value.

The integrated IRF for 2003-2018 is +0.53 W/m^2 +/ 0.11 with 0.40 W/m^2 +/- 0.1 being in the LW band. Modeling predicted the LW band to be 0.35 W/m^2 +/- 0.05 over this same period which implies good agreement between theory and observation.

In summary about 80% of the net heat uptake for the period 2003-2018 is the result of GHGs while 20% is the result of aerosol reductions. It used to be that aerosols were increasing which was suppressing the warming. They stabilized around 1980. But at least for this 15 year period efforts to reduce pollution are now contributing to the warming. This may explain why the EEI has increased to +0.87 W/m^2 +/- 0.12 (Schuckmann 2020) in recent years.

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Between the oceanic heat burial and the aerosols this is how a disaster can sneak up on a civilization. At it's core civilization is fundamentally unsustainable anyway.

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Between the oceanic heat burial and the aerosols this is how a disaster can sneak up on a civilization. At it's core civilization is fundamentally unsustainable anyway.

Well one like a hive type like the Borg in STNG would be. As a matter of fact we are being assimilated right now.

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On 4/6/2021 at 12:00 PM, bdgwx said:

Some of you probably saw news articles regarding the Kramer et al 2021 publication which for the first time measures the net instantaneous radiative force using CERES and AIRS between 2003 and 2018.

News Article: https://www.ecowatch.com/greenhouse-effect-nasa-study-2651319284.html

Official: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL091585 

Free: https://www.essoar.org/doi/10.1002/essoar.10506610.1

From the publication...

Total-IRF = +0.033 W/m2/year +/- 0.007
LW-IRF = +0.027 W/m2/year +/- 0.006
SW-IRF = +0.006 W/m2/year +/- 0.003

The SOCRATES radiative transfer model predicts LW-IRF to be +0.023 W/m2/year +/- 0.003. The model computes the RF for increases in most of the GHG species found in the atmosphere. Note that measurement and modeling are consistent here.

The MERRA reanalysis attributes +0.006 W/m2/year +/- 0.003 to aerosol declines. Note that this matches well with the measured value.

The integrated IRF for 2003-2018 is +0.53 W/m^2 +/ 0.11 with 0.40 W/m^2 +/- 0.1 being in the LW band. Modeling predicted the LW band to be 0.35 W/m^2 +/- 0.05 over this same period which implies good agreement between theory and observation .

In summary about 80% of the net heat uptake for the period 2003-2018 is the result of GHGs while 20% is the result of aerosol reductions. It used to be that aerosols were increasing which was suppressing the warming. They stabilized around 1980. But at least for this 15 year period efforts to reduce pollution are now contributing to the warming. This may explain why the EEI has increased to +0.87 W/m^2 +/- 0.12 (Schuckmann 2020) in recent years.

Good morning badger, thank you article/attachments. It seems that it’s DIY Do or DIY Don’t. As always .....

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On 4/6/2021 at 12:00 PM, bdgwx said:

Some of you probably saw news articles regarding the Kramer et al 2021 publication which for the first time measures the net instantaneous radiative force using CERES and AIRS between 2003 and 2018.

News Article: https://www.ecowatch.com/greenhouse-effect-nasa-study-2651319284.html

Official: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL091585 

Free: https://www.essoar.org/doi/10.1002/essoar.10506610.1

From the publication...

Total-IRF = +0.033 W/m2/year +/- 0.007
LW-IRF = +0.027 W/m2/year +/- 0.006
SW-IRF = +0.006 W/m2/year +/- 0.003

The SOCRATES radiative transfer model predicts LW-IRF to be +0.023 W/m2/year +/- 0.003. The model computes the RF for increases in most of the GHG species found in the atmosphere. Note that measurement and modeling are consistent here.

The MERRA reanalysis attributes +0.006 W/m2/year +/- 0.003 to aerosol declines. Note that this matches well with the measured value.

The integrated IRF for 2003-2018 is +0.53 W/m^2 +/ 0.11 with 0.40 W/m^2 +/- 0.1 being in the LW band. Modeling predicted the LW band to be 0.35 W/m^2 +/- 0.05 over this same period which implies good agreement between theory and observation.

In summary about 80% of the net heat uptake for the period 2003-2018 is the result of GHGs while 20% is the result of aerosol reductions. It used to be that aerosols were increasing which was suppressing the warming. They stabilized around 1980. But at least for this 15 year period efforts to reduce pollution are now contributing to the warming. This may explain why the EEI has increased to +0.87 W/m^2 +/- 0.12 (Schuckmann 2020) in recent years.

Just noodling some #. Doubled CO2 is 3.7 W/m2 so forcing increase is roughly 0.9% of doubled CO2 per year. GISS temperature increase over same period is .0229C per year giving a rough TCR of 2.6. Plenty of uncertainty in slopes due to short time-period, but warming and forcing both increasing at a good clip.

Giss trend - http://www.ysbl.york.ac.uk/~cowtan/applets/trend/trend.html

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7 minutes ago, csnavywx said:

That TCR value is quite high. 2.6 is on the upper end of most curves, iirc.

Yes, CMIP5 mean was 1.8. So probably too high. The period is short and there is other uncertainty.

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11 hours ago, csnavywx said:

That TCR value is quite high. 2.6 is on the upper end of most curves, iirc.

2.4-2.6 is the range that comes to mind when you look at Paleo-climate. However the datasets are always contested and people opt for the other thing.

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Sherwood 2020: An Assessment of Earth's Climate Sensitivity Using Multiple Lines of Evidence (official / free) suggests a TCR of 1.8C with 66% upper bound of 2.2C. If the PDF was normally distributed that would imply a 95% upper bound of 2.6C. However, the PDF is not normally distributed and has a long tail on the right side so 95% upper bound is likely higher than 2.6C. Sherwood 2020 is probably the most comprehensive study on climate sensitivity to date.

 

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So the big question...will the IPCC AR6 stick with the likely ECS of 1.5-4.5C or refine it?

Sherwood 2020's 1σ range is 2.6-3.9C and 2σ range is 2.3-4.7C.

The IPCC uses 66% as the standard for "likely". Using this standard with Sherwood 2020 an argument could be made for 2.5-4.0C. That would be a big change. I'm wondering if 2.0-4.0C might be a more reasonable choice for now.

With each passing decade we can constrain the lower bound further. I think at this point 1.5C is all but impossible at this point.

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12 minutes ago, bdgwx said:

Sherwood 2020: An Assessment of Earth's Climate Sensitivity Using Multiple Lines of Evidence (official / free) suggests a TCR of 1.8C with 66% upper bound of 2.2C. If the PDF was normally distributed that would imply a 95% upper bound of 2.6C. However, the PDF is not normally distributed and has a long tail on the right side so 95% upper bound is likely higher than 2.6C. Sherwood 2020 is probably the most comprehensive study on climate sensitivity to date.

 

Wouldn't modify sherwood 2020's conclusions based on my simple estimates. In addition to the caveats given above, the radiation paper notes that some forcing components are ignored - ozone and aerosol cloud. Agree with your last post though, ECS<2 seems very unlikely.

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