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Author Topic: Global Dimming - The aerosol masking effect  (Read 757 times)

harpy

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Global Dimming - The aerosol masking effect
« on: October 09, 2019, 09:31:40 PM »
There's a number of published papers demonstrating that the removal of the aerosol masking effect, AKA global dimming, will result in a rapid increase in global average temperature.  Above our current level, within a short period of time (weeks to months).

Depending on the reference, the figures apparently range from approximately 1C-3C of global average temperature rise is being "masked" by aerosol particulates in the atmosphere. 

Below are a number of peer-reviewed articles, and essays that focus exclusively on this subject, and propose varying numbers for the aerosol masking effect.

Hansen's 2011 Paper entitled, Earth's energy imbalance and implications informs us of a 1C global average temperature is not being fully realized due to the aerosol masking effect.

References:

Earth's energy imbalance and implications  https://pubs.giss.nasa.gov/abs/ha06510a.html

Cooling from atmospheric particles may mask greater warming  https://www.sustainability-times.com/environmental-protection/research-cooling-from-atmospheric-particles-may-mask-greater-warming/

The roles of aerosol direct and indirect effects in past and future climate change
 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/jgrd.50192

Aerosol-driven droplet concentrations dominate coverage and water of oceanic low-level clouds
 https://science.sciencemag.org/content/363/6427/eaav0566

The Aerosol Masking Effect: A Brief Overview  The Aerosol Masking Effect: A Brief Overview

« Last Edit: October 09, 2019, 09:41:10 PM by harpy »

Ken Feldman

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Re: Global Dimming - The aerosol masking effect
« Reply #1 on: October 11, 2019, 08:12:34 PM »
Harpy,

There's a forum in the Science section about aerosols.  We've shared many papers on the subject.

Recently, someone went to a talk by a scientist specializing in aerosols and asked about the warming that would occur if we stopped producing man-made aerosols suddenly.


Did the question about a possible spike in warming from reduced aerosols with the reduction in fossil fuel burning come up?  If so, what was the answer?

Yes, I actually asked about Hansen et al.'s 2013 paper on aerosol masking, and the effect that immediately stopping production of sulfates via oil/coal/etc. Dr. Haywood said he respected Dr. Hansen, but believed that the warming effect would not be as great or as rapid as Hansen described. Additionally, Dr. Haywood said that sulfates would be replaced with other aerosols that occur naturally, the names of which escape me.

harpy

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Re: Global Dimming - The aerosol masking effect
« Reply #2 on: October 13, 2019, 01:43:59 AM »
Harpy,

There's a forum in the Science section about aerosols.  We've shared many papers on the subject.

Recently, someone went to a talk by a scientist specializing in aerosols and asked about the warming that would occur if we stopped producing man-made aerosols suddenly.


Did the question about a possible spike in warming from reduced aerosols with the reduction in fossil fuel burning come up?  If so, what was the answer?

Yes, I actually asked about Hansen et al.'s 2013 paper on aerosol masking, and the effect that immediately stopping production of sulfates via oil/coal/etc. Dr. Haywood said he respected Dr. Hansen, but believed that the warming effect would not be as great or as rapid as Hansen described. Additionally, Dr. Haywood said that sulfates would be replaced with other aerosols that occur naturally, the names of which escape me.

That's not even the correct year of Hansen's paper. 

TerryM

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Re: Global Dimming - The aerosol masking effect
« Reply #3 on: October 13, 2019, 02:20:45 AM »
^^
Good catch ;)
Terry

sidd

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Re: Global Dimming - The aerosol masking effect
« Reply #4 on: October 13, 2019, 06:03:54 AM »
Re: Hansen, aerosol forcing, 2013

DOI: 10.1007/978-3-7091-0973-1_2 , technically in published 2012, but has extensive discussion of aerosol effect

Hansen and Sato, Paleoclimate Implications for Human-Made Climate Change, A. Berger et al. (eds.), Climate Change, Springer-Verlag Wien 2012

2013 was his royal society paper too, but the one cited above has better review of aerosol.

sidd


bluesky

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Re: Global Dimming - The aerosol masking effect
« Reply #5 on: October 18, 2019, 01:27:18 AM »
aerosol part of global warming in some instance

"Greenhouse gases may get more attention, but aerosols — from car exhaust to volcanic eruptions — also have a major impact on the Earth’s climate. Using a massive NASA dataset, Yale researchers have created a framework that helps explain just how sensitive local temperatures are to aerosols."

https://environment.yale.edu/news/article/how-aerosols-affect-our-climate/

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL083812

Abstract (Geophysical Research Letter)
Abstract
"Aerosol impact on the surface temperature varies between the shortwave and the longwave components of radiation, depends on the time of the day, and is modulated by underlying biophysical processes. We disentangle these complexities by isolating the direct surface shortwave and longwave radiative effects from a global reanalysis data product and calculating their spatially explicit climate sensitivities. Higher sensitivity is found for the longwave component and is driven by a combination of spatial variability of aerosol species and biophysical control of the underlying surface. The opposing shortwave and longwave effects reduce the global mean diurnal temperature range by 0.47 K, with almost half the contribution coming from aerosols of anthropogenic origin. We also find evidence of an increasing trend in the local climate sensitivity in the equatorial zone, possibly caused by deforestation. These surface processes can partially explain why the climate forcing efficacy of aerosols exceeds unity.
Plain Language Summary
The radiative effect of aerosols is disproportionately stronger at the Earth's surface compared to the top of the atmosphere and depends on the time of the day and aerosol properties. Moreover, the local surface temperature response to aerosols depends on both incoming energy and the surface energy dissipation via the properties of the underlying surface. To disentangle these complex interactions, we use a theoretical framework to separate surface temperature response to the aerosol shortwave and longwave radiative effects for the world's land surfaces using a reanalysis dataset. We find a stronger local climate sensitivity to the longwave radiative effect than to the shortwave. This is partly due to the incidental collocation of regions of high local climate sensitivity with regions containing coarse mineral dust aerosols. The opposite directions of the surface shortwave and longwave radiative effects reduce the diurnal temperature range, particularly in arid regions. Long‐term trends show an intensification of the local climate sensitivity in the tropics due to deforestation, demonstrating the importance of local biophysical processes in aerosol‐climate interactions. The addition of this biophysical control may partially explain why the global climate sensitivity to aerosols is stronger than that due to well‐mixed greenhouse gases."


harpy

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Re: Global Dimming - The aerosol masking effect
« Reply #6 on: October 30, 2019, 02:19:41 PM »
Re: Hansen, aerosol forcing, 2013

DOI: 10.1007/978-3-7091-0973-1_2 , technically in published 2012, but has extensive discussion of aerosol effect

Hansen and Sato, Paleoclimate Implications for Human-Made Climate Change, A. Berger et al. (eds.), Climate Change, Springer-Verlag Wien 2012

2013 was his royal society paper too, but the one cited above has better review of aerosol.

sidd

OK, so there's a 2013 paper.

That rebuttal discounted Hansens research without being able to remember any details?