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DrTskoul

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Re: The Science of Aerosols
« Reply #200 on: August 03, 2019, 09:59:32 PM »
Weak average liquid-cloud-water response to anthropogenic aerosols

Thanks, important article. Lame that they didn't pay for open access though. There's an editorial on it here: https://www.nature.com/articles/d41586-019-02287-z


Last paragraph of the conclusion:
Quote
The cancellations between increases and decreases in LWP that we have observed in liquid clouds downwind of different aerosol sources under a wide range of meteorological conditions is in stark contrast to the unidirectional aerosol-induced increases in the LWP simulated by 45 GCMs . Although in multiple GCMs an increase in the LWP enhances the Twomey effect by more than 100%45, our analysis of pollution tracks show that decreases in the LWP in fact offset 23% of the Twomey effect. The compensation between increases and decreases in the LWP in pol- lution tracks agrees with the bidirectional LWP responses found in idealized process-level model simulations15–17 and in global satellite observations of maritime clouds19,20. Now, our analysis of pollution tracks shows with unprecedented confidence that the global average LWP response to anthropogenic aerosols is weak. We expect this con- straint on the LWP response based on observations of pollution tracks to lead to improved aerosol-cloud parameterizations in GCMs and to translate into reduced uncertainty in aerosol forcing calculations and more reliable projections of future climate.

Hope they're on the right track. The number of assumptions and limitations is frightening.

Lame indeed, should have been open access...

Reginald

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Re: The Science of Aerosols
« Reply #201 on: August 04, 2019, 03:28:22 AM »
Speaking of Aerosols, but not inside clouds.

Harvard creates advisory panel to oversee solar geoengineering project
https://www.nature.com/articles/d41586-019-02331-y

Nature, July 2019

Scientists will inject particles of calcium carbonate into the atmosphere and study their effects on incoming sunlight.

Plans to test a technique that would cool the planet by blocking sunlight are one step closer to reality. Harvard University in Cambridge, Massachusetts, has created an external advisory panel to examine the potential ethical, environmental and geopolitical impacts of this geoengineering project, which has been developed by the university’s researchers.

Known as the Stratospheric Controlled Perturbation Experiment (SCoPEx), the project would involve the release of calcium carbonate particles from a steerable balloon some 20 kilometres above the southwestern United States.

Louise Bedsworth, executive director of the California Strategic Growth Council, a state agency that promotes sustainability and economic prosperity, will lead the Harvard advisory panel, the university said on 29 July. The other seven members include Earth-science researchers and specialists in environmental and climate law and policy.


DrTskoul

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Re: The Science of Aerosols
« Reply #202 on: August 04, 2019, 02:35:51 PM »
And somehow I shudder to the idea...
« Last Edit: August 04, 2019, 09:42:28 PM by DrTskoul »

TerryM

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Re: The Science of Aerosols
« Reply #203 on: August 04, 2019, 09:03:08 PM »
And somehow I shudder  to the idea...


While I'm sure that Harvard has been given a thumbs up by all of the worlds various political bodies, I can't but feel the pain this will cause to the installed base of PV and Solar Thermal facilities.


Will the diurnal winds that spin so many turbines be effectively muted in the dim days ahead, and what will become of the marginal northern farms that are limited today not by temperature, but by the seasonal lack of solar radiation. At one time these farms were seen by some as the answer to failing agriculture in more southern climes.


Just because we've made some minor errors - Australian Cane Toads, The Grand Banks Fisheries and  Mono Culture Forestry spring to mind - is no indication that this time won't be, almost uniquely, successful.


Harvard itself has an unblemished reputation - ask any Slav, but even the brightest and the best have been known to err on the side of hubris.
Terry

jai mitchell

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Re: The Science of Aerosols
« Reply #204 on: August 05, 2019, 08:20:50 PM »
More on the recent "good news"
https://phys.org/news/2019-08-pollution-wont-global-spike.html

Quote
meaning pollution is unlikely to offset more than half of greenhouse gas warming.

our current top of atmosphere energy imbalance as measured by the ocean heat content increases (SEE NODC OHC) is 0.6 Watts per meter squared.  The total forcing from GHGs is about 2.4 Watts per meter squared.  This means that some large portion of the total forcing is being offset by aerosols.  if less than half we still have the 0.6 Watts per meter squared being experienced PLUS the (estimate) 1.0 Watts per meter squared from aerosols.  to reach equilibrium)  Since methane is about 20% of the current forcing and other short lived climate pollutants balancing each other out,

even this 'good news' study indicates that we still have about 1.6 Watts per meter squared of globally averaged annual forcing to be worked through the system before reaching temperature equilibrium.

This does not include the longer term climate warming feedbacks due to carbon cycle emissions as the earth warms from the 1.6 Watts per meter equilibrium warming.
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Oscillidous

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Re: The Science of Aerosols
« Reply #205 on: August 19, 2019, 10:20:57 PM »
Regarding this recent paper, I don't know of many other papers exploring the idea that reduced droplet formation in clouds is what is responsible for greater cooling, it's the reflective of the particulates themselves, no? Seems to me the equivalent of saying "good news, fire doesn't cause as much frostbite as previously thought" when obviously no one was even considering the possibility.

The paper in Nature recording localized temperature change over North America 3 days after 9/11 is an example of observed warming as a result from absence of some anthropocentric aerosols, which at least to my laymen understanding seems to be a better analogue for what to expect as a result of reduced industrial output.
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Ktb

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Re: The Science of Aerosols
« Reply #206 on: August 26, 2019, 01:12:38 PM »
Got to hear Dr. Jim Haywood from Exeter University and the Met Office speak today about Aerosol masking, clouds, and possible future geoengineering. He agreed to provide me his powerpoint presentation. I will try to upload it here when I obtain it.

Edit: Jim** Haywood
« Last Edit: August 26, 2019, 02:51:20 PM by Ktb »
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TerryM

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Re: The Science of Aerosols
« Reply #207 on: August 26, 2019, 01:30:59 PM »
Got to hear Dr. James Haywood from Exeter University and the Met Office speak today about Aerosol masking, clouds, and possible future geoengineering. He agreed to provide me his powerpoint presentation. I will try to upload it here when I obtain it.
Looking forward to it.
Terry

Ktb

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Re: The Science of Aerosols
« Reply #208 on: September 04, 2019, 04:44:28 PM »
Having a million difficulties trying to upload the presentation as a PDF.

I tried to take detailed notes, and stuck around for the Q&A. I may be able to answer some basic questions if anybody has any.
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blumenkraft

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Re: The Science of Aerosols
« Reply #209 on: September 04, 2019, 04:59:15 PM »
Having a million difficulties trying to upload the presentation as a PDF.


The download works well. Thank you!
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Ken Feldman

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Re: The Science of Aerosols
« Reply #210 on: September 04, 2019, 11:15:55 PM »
Having a million difficulties trying to upload the presentation as a PDF.

I tried to take detailed notes, and stuck around for the Q&A. I may be able to answer some basic questions if anybody has any.

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?

Ktb

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Re: The Science of Aerosols
« Reply #211 on: September 05, 2019, 01:31:42 AM »

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.
« Last Edit: September 05, 2019, 02:02:20 AM by Ktb »
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Ken Feldman

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Re: The Science of Aerosols
« Reply #212 on: September 05, 2019, 08:02:49 PM »
Thanks.  Here's a paper that discusses variability of natural aerosols.

https://www.nature.com/articles/nature12674

Quote
Large contribution of natural aerosols to uncertainty in indirect forcing
K. S. Carslaw, L. A. Lee, C. L. Reddington, K. J. Pringle, A. Rap, P. M. Forster, G. W. Mann, D. V. Spracklen, M. T. Woodhouse, L. A. Regayre & J. R. Pierce

Nature volume 503, pages 67–71 (07 November 2013)

Abstract

The effect of anthropogenic aerosols on cloud droplet concentrations and radiative properties is the source of one of the largest uncertainties in the radiative forcing of climate over the industrial period. This uncertainty affects our ability to estimate how sensitive the climate is to greenhouse gas emissions. Here we perform a sensitivity analysis on a global model to quantify the uncertainty in cloud radiative forcing over the industrial period caused by uncertainties in aerosol emissions and processes. Our results show that 45 per cent of the variance of aerosol forcing since about 1750 arises from uncertainties in natural emissions of volcanic sulphur dioxide, marine dimethylsulphide, biogenic volatile organic carbon, biomass burning and sea spray. Only 34 per cent of the variance is associated with anthropogenic emissions. The results point to the importance of understanding pristine pre-industrial-like environments, with natural aerosols only, and suggest that improved measurements and evaluation of simulated aerosols in polluted present-day conditions will not necessarily result in commensurate reductions in the uncertainty of forcing estimates.

jai mitchell

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Re: The Science of Aerosols
« Reply #213 on: September 09, 2019, 09:38:39 PM »
Having a million difficulties trying to upload the presentation as a PDF.

I tried to take detailed notes, and stuck around for the Q&A. I may be able to answer some basic questions if anybody has any.

interesting to see what happened to arctic sea ice and the development of "the blob" in the north east pacific ocean after the 2014 eruption in iceland.
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morganism

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Re: The Science of Aerosols
« Reply #214 on: September 19, 2019, 03:22:48 AM »
Dust from a giant asteroid crash caused an ancient ice age

http://www.fieldmuseum.org/about/press/dust-giant-asteroid-crash-caused-ancient-ice-age

“Our hypothesis is that the large amounts of extraterrestrial dust over a timeframe of at least two million years played an important role in changing the climate on Earth, contributing to cooling,” says Heck.

“Our results show for the first time that such dust, at times, has cooled Earth dramatically,”


Richard Rathbone

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Re: The Science of Aerosols
« Reply #215 on: September 19, 2019, 11:59:25 PM »
Having a million difficulties trying to upload the presentation as a PDF.

I tried to take detailed notes, and stuck around for the Q&A. I may be able to answer some basic questions if anybody has any.

That looks quite promising for the next generation of climate models. Its seems we finally have enough measurements of aerosols to be able to have robust arguments about what sort of modelling approach makes sense rather than crossing fingers and praying that we haven't overfitted too badly.

Ktb

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Re: The Science of Aerosols
« Reply #216 on: September 21, 2019, 02:36:00 PM »
Glad everybody enjoyed the read. The presentation was fantastic. Excellent speaker.
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jai mitchell

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Re: The Science of Aerosols
« Reply #217 on: September 27, 2019, 01:45:22 AM »
Study on the aerosol impact of the 2014-2015 eruption of Bárðarbunga in Iceland


https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2015GL067070

Observations of a substantial cloud-aerosol indirect effect
during the 2014–2015 Bárðarbunga-Veiðivötn
fissure eruption in Iceland
Daniel T. McCoy1 and Dennis L. Hartmann

Quote
The estimated changes in upwelling SW and cloud albedo over the first 2 months of the eruption due to anomalies in re are shown in Figure 4. Cloud albedo was estimated to increase by up to 3% in the Norwegian Sea and Greenland Sea (Figure 4b). Local increases in upwelling SW exceeded 2 W/m^2. The zonal mean upwelling SW across the 60°N–70°N latitude band was estimated to increase by 1 W /m*2, and the cloud albedo was estimated to increase by 1.5% (Figure 4

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wdmn

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Re: The Science of Aerosols
« Reply #218 on: January 07, 2020, 09:22:39 PM »
New study on the negative forcing of aerosols:

Ensembles of Global Climate Model Variants Designed for the Quantification and Constraint of Uncertainty in Aerosols and Their Radiative Forcing

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019MS001628

Abstract
Tropospheric aerosol radiative forcing has persisted for many years as one of the major causes of uncertainty in global climate model simulations. To sample the range of plausible aerosol and atmospheric states and perform robust statistical analyses of the radiative forcing, it is important to account for the combined effects of many sources of model uncertainty, which is rarely done due to the high computational cost. This paper describes the designs of two ensembles of the Met Office Hadley Centre Global Environment Model‐U.K. Chemistry and Aerosol global climate model and provides the first analyses of the uncertainties in aerosol radiative forcing and their causes. The first ensemble was designed to comprehensively sample uncertainty in the aerosol state, while the other samples additional uncertainties in the physical model related to clouds, humidity, and radiation, thereby allowing an analysis of uncertainty in the aerosol effective radiative forcing. Each ensemble consists of around 200 simulations of the preindustrial and present‐day atmospheres. The uncertainty in aerosol radiative forcing in our ensembles is comparable to the range of estimates from multimodel intercomparison projects. The mean aerosol effective radiative forcing is −1.45 W/m2 (credible interval of −2.07 to −0.81 W/m2), which encompasses but is more negative than the −1.17 W/m2 in the 2013 Atmospheric Chemistry and Climate Model Intercomparison Project and −0.90 W/m2 in the Intergovernmental Panel on Climate Change Fifth Assessment Report. The ensembles can be used to reduce aerosol radiative forcing uncertainty by challenging them with multiple measurements as well as to isolate potential causes of multimodel differences.


According to Eric Holthous:

"This study implies that there's an additional 1°C or so of warming baked in to aerosol pollution worldwide.

This study means we've warmed the planet more than we thought, it's just been hidden."

https://twitter.com/EricHolthaus/status/1214575877410971649


So we're at ~2.2C now, (plus emissions of last decade)... ambitious is now 3C it would seem.

TerryM

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Re: The Science of Aerosols
« Reply #219 on: January 08, 2020, 10:16:13 PM »
^^
IIRC +1.5 - +2.0C is where the runaway greenhouse effects were supposed to kick in. When albedo changes and permafrost melt take over from AGW & push temperature and sea level rise into high gear. A gear that speeds us to civilizational collapse.


I don't think anyone has claimed that we can sustain 3C, so if short term aerosols are all that's keeping the lid on we may be facing a short journey.


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wdmn

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Re: The Science of Aerosols
« Reply #220 on: January 13, 2020, 12:21:33 AM »
^^^
In regards to the paper posted above, I should note that it's unclear as to whether this study treats aerosols in the same way as AR5, i.e. this study includes "natural" aerosols such as sand and salt, whereas AR5 seems to only include anthropogenic aerosols in its -0.9 w/m2 forcing.

However, counterintuitively, the discussion from the paper suggests that including these natural aerosols actually reduces the forcing:

"The global mean 1850–2008 aerosol RFs are −2.12 (credible interval −2.76, −1.47) W/m2 (RF) based on the AER PPE and −1.45 (−2.07, −0.81) W/m2 (ERF) based on the AER‐ATM PPE. There are several factors that contribute to the weaker forcing in AER‐ATM. First, more natural aerosols (sea spray, DMS, and dust) are typically emitted in AER‐ATM than in AER... Larger natural aerosol emissions in both 1850 and 2008 reduce the magnitude of the aerosol‐cloud interaction (Carslaw, Lee, Reddington, Pringle, et al., 2013)."

In other words, when fewer natural aerosols were included, the mean forcing went up to -2.12 w/m2.

It should also be noted that these were the aerosol estimates for 2008. So, it is quite possible they have gone down now as China has made an effort to clean up their pollution. James Hansen seems to think that's the reason for the accelerated warming in the last 5 years.

TerryM

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Re: The Science of Aerosols
« Reply #221 on: January 14, 2020, 12:26:47 AM »
Ya But, ya but - Hansen thinks? - Holy Shit!
Terry ???

jai mitchell

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Re: The Science of Aerosols
« Reply #222 on: January 14, 2020, 02:59:05 AM »
^^^
In regards to the paper posted above, I should note that it's unclear as to whether this study treats aerosols in the same way as AR5, i.e. this study includes "natural" aerosols such as sand and salt, whereas AR5 seems to only include anthropogenic aerosols in its -0.9 w/m2 forcing.


The AR5 forcing parameters can be found here:  http://www.pik-potsdam.de/~mmalte/rcps/  The direct aerosol forcing includes anthropogenic and natural aerosols (like mineral dust) and they include the indirect forcing in the total cloud effect forcing parameter which combined comes out to about -0.9 W/m^2. 
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wdmn

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Re: The Science of Aerosols
« Reply #223 on: January 14, 2020, 04:22:42 AM »
Thanks JM.

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Re: The Science of Aerosols
« Reply #224 on: January 14, 2020, 06:12:19 AM »
Can someone explain to me what -0.9 W/m^2 means in regards to temperature?
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wdmn

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Re: The Science of Aerosols
« Reply #225 on: January 14, 2020, 06:37:13 AM »
James Hansen gives the number of  0.75 ± 0.25°C per W/m2.

So the -0.9 W/m2 number from AR5 would give ~0.68 degrees C of warming masked by aerosols.

Using the -1.45 W/m2 number from the new paper linked above we get ~1.1 degrees C.

Either way you've got to believe we're well over 1.5C of warming already (plus additional warming from last 10 years of emissions). I'd say (and no one has shown how to get another answer from the math) realistically we're approaching ~2.5C of warming locked in. That means we're desperately scrambling (or we should be) to avoid hitting 3C based on our emissions over the next 2 decades.

Source with Hansen's number:
http://www.columbia.edu/~jeh1/mailings/2018/20181206_Nutshell.pdf

Wherestheice

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Re: The Science of Aerosols
« Reply #226 on: January 14, 2020, 07:03:59 AM »
James Hansen gives the number of  0.75 ± 0.25°C per W/m2.

So the -0.9 W/m2 number from AR5 would give ~0.68 degrees C of warming masked by aerosols.

Using the -1.45 W/m2 number from the new paper linked above we get ~1.1 degrees C.

Either way you've got to believe we're well over 1.5C of warming already (plus additional warming from last 10 years of emissions). I'd say (and no one has shown how to get another answer from the math) realistically we're approaching ~2.5C of warming locked in. That means we're desperately scrambling (or we should be) to avoid hitting 3C based on our emissions over the next 2 decades.

Source with Hansen's number:
http://www.columbia.edu/~jeh1/mailings/2018/20181206_Nutshell.pdf

Ah okay, I see. Thank you for explaining. Yeah I don't see us staying below 2 C at this point.The new target needs to be avoiding 3 C.

In that paper that you linked that had the -1.45 W/m2 figure, do we know how much the natural aerosols are blocking? Vs how much the human related aerosols are blocking? I think the latter part of that question is the most important part of this whole discussion.
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Re: The Science of Aerosols
« Reply #227 on: January 14, 2020, 07:09:41 AM »
A metaphor:

Noun

runaway (plural runaways)

   2. A vehicle (especially, a train) that is out of control.


That seems to describe civilisation to me.
'We' think we still have control but nobody is steering our train.
The tracks ahead are bending down because of increasing natural GHG sources, moving our train onto a increasingly declined track... 'Falling'
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Re: The Science of Aerosols
« Reply #228 on: January 14, 2020, 07:57:52 AM »
@wherestheice
All I can say with certainty is that they created two models, and one included fewer natural aerosols. The one with fewer natural aerosols had a stronger negative forcing of -2.12 W/m^2; so the natural aerosols have a warming effect via cloud feedbacks (apparently).

A RF of -2.12 W/m^2 for anthro aerosols would be equivalent to ~1.6C of masked warming. But I am not sure that this is a fair extrapolation to make... It would certainly be a much higher number than anyone has previously suggested. (It would mean we would have to reconsider things like ECS and TCR).

The ~1.45 number fits with the estimated RFs from CO2 and other GHGs given by Hansen, with the combined total being roughly 3 W/m^2. If -1.45 W/m2 is masked by aerosols it means we should have recorded around 1.16 degrees of warming over the 280ppm earth (which is right about where we are).

Wish I could say more; I've found it difficult to get straight answers on this when I have asked, and I don't understand enough about the modelling.

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Re: The Science of Aerosols
« Reply #229 on: January 14, 2020, 04:01:32 PM »

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.

The reduction of anthropogenic aerosols won't happen that fast.
Yes, the world is getting off the coal, but we have another two decades of oil burning on the same levels as today.
My hypothesis: the reduction in aerosols (+ve effect) will be matched by a reduction in FF emissions (-ve effect) so that the net warming effect from GHG will remain on the same level.

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Re: The Science of Aerosols
« Reply #230 on: January 14, 2020, 04:05:53 PM »

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.

The reduction of anthropogenic aerosols won't happen that fast.
Yes, the world is getting off the coal, but we have another two decades of oil burning on the same levels as today.
My hypothesis: the reduction in aerosols (+ve effect) will be matched by a reduction in FF emissions (-ve effect) so that the net warming effect from GHG will remain on the same level.
GHGs remain in the atmosphere decades to millennia.
Aerosols remain in the atmosphere days to months.
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Re: The Science of Aerosols
« Reply #231 on: January 14, 2020, 06:30:53 PM »
Thanks for giving the voice of reason Tom :).
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Re: The Science of Aerosols
« Reply #232 on: January 14, 2020, 09:46:31 PM »

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.

The reduction of anthropogenic aerosols won't happen that fast.
Yes, the world is getting off the coal, but we have another two decades of oil burning on the same levels as today.
My hypothesis: the reduction in aerosols (+ve effect) will be matched by a reduction in FF emissions (-ve effect) so that the net warming effect from GHG will remain on the same level.
GHGs remain in the atmosphere decades to millennia.
Aerosols remain in the atmosphere days to months.

My point was that the reduction of aerosols will take considerable time, on a scale of multiple decades. And a lot will happen with GHG emissions during that time, which is a counterbalancing effect.

Another point is that aerosols have mostly a local or regional effect, whereas GHG have a global effect. Aerosols are estimated to increase for some years to come in e.g. SE Asia.

The main GHG is water vapor, and it remains in the atm. for a few days only during the hydrological cycle. The theory says that when aerosols are reduced, we get less cloudiness, thus less water vapor. And less cooling effect.

However this is theory, in practice we have seen examples of the opposite effects. As in this research:
"Response of the atmospheric hydrological cycle over the tropical Asian monsoon regions to anthropogenic aerosols and its seasonality" by Takahashi et al, 2018, show that:
"The results show that, as a whole, the Asian monsoon precipitation is reduced by the increase in aerosol loading during boreal summer and winter. This decrease in precipitation corresponds to a decrease in precipitable water due to the cooling in surface air temperature (SAT), mainly over adjacent oceans. The cooling is explained by the sum of the direct and indirect effects of aerosols. A modulation of the Walker circulation occurs, which can be explained by the east-west horizontal SAT gradient over the tropics due to the spatially heterogeneous increase in aerosols. "

https://progearthplanetsci.springeropen.com/articles/10.1186/s40645-018-0197-2



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Re: The Science of Aerosols
« Reply #233 on: January 14, 2020, 10:50:04 PM »
Hefaistos,

While it might take a while to clean up our aerosols, ~1.1C of masked warming still means ~1.1C of masked warming. It means that -- best case scenario -- if we went to zero emissions tomorrow we'd still approach 2.5C of warming since preindustrial.

So, while you suggest that the longer it takes us to reduce our emissions (and so to clean up aerosols) the more time we buy ourselves, in fact, the opposite is true. The longer it takes, the more screwed we are, since that ~1.1C is already there, waiting, even if the rate of temp. rise from emissions goes down (it won't for sometime based on the last 10 years, and what's likely over the next 10) we are unlikely to avoid catastrophic levels of warming. We need to reach zero emissions as soon as possible. No matter how quickly or slowly we do that, we will find ourselves in a much warmer world.

Finally, the paper in question accounts for warming from cloud feedbacks from aerosols, but these tend to be from non-anthro sources, as already discussed in this thread.

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Re: The Science of Aerosols
« Reply #234 on: January 14, 2020, 11:02:19 PM »
Hefaistos,

While it might take a while to clean up our aerosols, ~1.1C of masked warming still means ~1.1C of masked warming. It means that -- best case scenario -- if we went to zero emissions tomorrow we'd still approach 2.5C of warming since preindustrial.

So, while you suggest that the longer it takes us to reduce our emissions (and so to clean up aerosols) the more time we buy ourselves, in fact, the opposite is true. The longer it takes, the more screwed we are, since that ~1.1C is already there, waiting, even if the rate of temp. rise from emissions goes down (it won't for sometime based on the last 10 years, and what's likely over the next 10) we are unlikely to avoid catastrophic levels of warming. We need to reach zero emissions as soon as possible. No matter how quickly or slowly we do that, we will find ourselves in a much warmer world.

Finally, the paper in question accounts for warming from cloud feedbacks from aerosols, but these tend to be from non-anthro sources, as already discussed in this thread.

much of those emissions are organic carbon which are primarily produced through biomass burning.  so they won't all go away.

Much will go away and of these, over time, it is projected that ch4 levels will also go down that will help reduce the overall burden.  Of course the uncertainty and (VERY LIKELY IN MY OPINION) rapid increase in carbon cycle emissions from warming soils will provide more than this uncertainty in future committed warming.

edit:

but we still have to accept that the current top of atmosphere energy imbalance is between 0.8 and 1.2 Watts per meter squared (even with the aerosol masking!).
« Last Edit: January 14, 2020, 11:47:47 PM by jai mitchell »
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Re: The Science of Aerosols
« Reply #235 on: January 15, 2020, 12:32:43 AM »
JM,

Thanks for the clarification.

Do you have a source for that energy imbalance? Hansen says, "Increasing the amount of CO2 from its pre-industrial level (280 ppm) to the 2018 amount (407 ppm) causes a climate forcing of ~2.1 W/m2," and, "Non-CO2 GHGs cause a climate forcing today [in 2018], relative to preindustrial conditions of more than 1 W/m2."

So that would put us at more than 3.1 W/m^2 in 2018. How much of the 0.8-1.2 you mentioned included in that?

Right now we're in the situation that aerosols seem to have declined (due to Chinese clean coal, etc), but methane growth in the atmosphere is accelerating... I agree that this is unlikely to continue, though more recent science does suggest that we are closer to frozen soil feedbacks being a problem than has previously been assumed.


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Re: The Science of Aerosols
« Reply #236 on: January 15, 2020, 01:05:57 AM »
Maybe this paper can help straighten things out a bit?

Their conclusion is that a 35-80% reduction in human emissions would cause a 1 C rise in temp.

And it looks like they don't include BB in their calculations.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/jgrd.50192

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Re: The Science of Aerosols
« Reply #237 on: January 15, 2020, 01:09:50 AM »
Also this.... "the climate and extreme event responses to a removal of anthropogenic aerosols, from a world with around 1.5°C GHG‐dominated warming. Global surface temperature is predicted to increase by 0.7°C (multimodel mean, model range is 0.5–1.1°C), while the land surface warms by 1.0°C (model range 0.7–1.6). As sulfate is the dominant aerosol surface temperature driver for present‐day emissions"

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017GL076079
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Re: The Science of Aerosols
« Reply #238 on: January 15, 2020, 01:21:58 AM »
this is a good and recent one, the values quoted are slightly lower than what I cited but they are based on 15 year period averages and are ocean heat content not EEI  I thought there was some recent work showing higher EEI values but don't see it at the moment.

https://www.frontiersin.org/articles/10.3389/fmars.2019.00432/full
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Re: The Science of Aerosols
« Reply #239 on: January 15, 2020, 05:51:25 AM »
Thanks Wherestheice.
-

Are airborne microplastics considered as aerosols?

The billions of rolling car tyres around the world keep on shedding them (emitting) for the foreseeable future.
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Re: The Science of Aerosols
« Reply #240 on: January 15, 2020, 06:29:36 AM »
Thanks Wherestheice.
-

Are airborne microplastics considered as aerosols?

The billions of rolling car tyres around the world keep on shedding them (emitting) for the foreseeable future.

Seems like they could be, see here... https://earther.gizmodo.com/microplastics-are-airborne-polluted-arctic-snow-reveal-1837239022

"There’s even a chance that the microplastic bits could end up acting like other tiny particles known as aerosols. "
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Re: The Science of Aerosols
« Reply #241 on: January 15, 2020, 10:53:47 AM »
Thanks for the link. I could've made that search myself, sorry for being lazy there.

I think it is high time that scientists investigate this all pervasive and permanent microplastic pollution. Not just its effects on lifeforms and foodchains/endocrine systems.
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Re: The Science of Aerosols
« Reply #242 on: February 12, 2020, 08:27:19 PM »
I bet that there is a discernible strong northern hemisphere GMST signal that occurred between Jan 21st 2020 and through February 15th (and possibly longer) due to China coronavirus quarantine and lunar new year extension.

January was the warmest on record, perhaps February will be also?
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Re: The Science of Aerosols
« Reply #243 on: February 12, 2020, 10:50:59 PM »
On the brighter side, some scientists have found that minor changes in altitude of jets would get rid of much of the warming contrail cover:
https://www.sciencedaily.com/releases/2020/02/200212121959.htm

 

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Re: The Science of Aerosols
« Reply #244 on: February 17, 2020, 06:37:40 PM »
https://carnegiescience.edu/news/do-climate-effects-air-pollution-impact-global-economy

Do The Climate Effects Of Air Pollution Impact The Global Economy?

Quote
Estimates indicate that aerosol pollution emitted by humans is offsetting about 0.7 degrees Celsius, or about 1.3 degrees Fahrenheit, of the warming due to greenhouse gas emissions,” said lead author Zheng. “This translates to a 40-year delay in the effects of climate change. Without cooling caused by aerosol emissions, we would have achieved 2010-level global mean temperatures in 1970.”

Previous research has shown that climate change provides some economic benefits to countries in cool regions—which would be warmed to temperatures that are ideal for agricultural productivity and human labor—and economic harm to countries in already hot regions.
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Re: The Science of Aerosols
« Reply #245 on: March 21, 2020, 03:42:00 AM »
S E A   R E S E A R C H   S O C I E T Y ' S   A P P E A L   T O
T H E  G O V E R N M E N T S  W O R L D - W I D E  :

WORLD GOVERNMENTS MUST LEARN FROM CORONAVIRUS EMISSIONS SHUTDOWN AS MUCH AS POSSIBLE

Global Circulation Models (GCMs) are computer models of the world's atmosphere based on observations and assumptions if there are no direct information available. World emissions shutdowns are a novel opportunity to learn about how climate system responds under different circumstances that cannot be normally experimentally checked. It is vitally important for the world's governments not to shut down meteorological measurements. Indeed, efforts must increase to use opportunity to test and search regional responses of the highly unusual situation. World Meteorological Organisation (WMO) and national meteorological organisations must quickly come up with new research proposals to gain every possible bit of information as this helps to understand how world's climate will respond as the world moves towards ZERO emissions. It is a tremendous tragedy if this unique opportunity to find more about how our atmosphere operates is lost. We do not foresee many situations like this rising when large world regions turn their lights off one after another. Modelling SO2, N2O, O3, CFC, CO2, CH4, CO shut downs.

Sponsors, please look at serious proposals to make research offers right now!
Let's make something positive happen out of this coronavirus calamity.

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Re: The Science of Aerosols
« Reply #246 on: March 21, 2020, 10:20:07 AM »
^^
Ramen!!
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Re: The Science of Aerosols
« Reply #247 on: March 21, 2020, 11:36:21 AM »
Yes, let's keep recording the weather no matter what. F.e. the North Pacific record after China shut down will be of exceptional interest.
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Re: The Science of Aerosols
« Reply #248 on: April 13, 2020, 01:27:34 AM »
Now that much industry has been shut down for weeks, can we detect any heating from aerosol reduction?
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Re: The Science of Aerosols
« Reply #249 on: April 16, 2020, 03:58:06 PM »
Earth is way dustier than we thought. That may be a problem for climate forecasts.

...

Dust in the upper atmosphere interacts with clouds, oceans and even radiation, or heat, from the sun. It can affect weather, precipitation and even has an impact on climate change. In a new study, scientists from the University of California Los Angeles (UCLA) found that there is four times as much coarse dust in our planet's atmosphere than has previously be seen in climate models.

There is more than one type of dust. In Earth's atmosphere, there is fine dust that is easily picked up by winds in dry areas, as well as coarser dust made of larger grains often from desert regions_ that can actually contribute to global warming in a similar way to greenhouse gases, according to a statement from UCLA. These large, coarse particles absorb radiation coming in from the sun and leaving the Earth, trapping that radiation on our planet. So, it's important for researchers to understand how much dust, especially course dust, is floating around in the atmosphere.

...

This team analyzed dozens of dust observations made by aircraft and compared them to how much dust current climate models predict should be in the atmosphere. And, while climate models predict only about 4 million metric tons, the team found that there is closer to 17 metric tons of coarse dust in our atmosphere.

"When we compared our results with what is predicted by current climate models, we found a drastic difference," study co-author Jasper Koka, a UCLA associate professor of atmospheric and oceanic sciences, said in the statement.

he team also found that dust particles also stay in the air longer than expected. This could mean that, since they're in the atmosphere for longer, they fall back to Earth much farther from the location where they were first picked up by the wind. So dust from a desert could affect ocean ecosystems and even increase how much carbon dioxide oceans absorb, according to the statement.

https://www.space.com/earth-atmosphere-dustier-thought-climate-models.html

Climate models miss most of the coarse dust in the atmosphere
https://advances.sciencemag.org/content/6/15/eaaz9507/
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