Global Dimming - The aerosol masking effect

[harpy]

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

[Sciguy]

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]

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]

^^
Good catch
Terry

[sidd]

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]

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]

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?

[longwalks1]

Not so much a post but a place marker to redirect any chatter about the effect of  the pandemic on a drop in aerosols via less cruises, shipping (nasty bunker fuel) and also reduced air transport.  And even possibly a dip in coal burning for smelting and electrical generation due to possible economic contraction.   

[Zinc_wit]

I was wondering about some comments I Saw floating around recently, is it actually plausible that we could reach a 2 degrees Celsius warming this summer as a result of aerosols dissapearing during this corona situation? Or is this just speculation?

[wili]

I believe this is the number floated by Guy McPherson a while back as what absolutely will happen, based on the very highest end of a range from an early study that has since been superseded by many other studies that show much lower likely effects.

Others here can probably dig up the specific relevant studies for you

[Tom_Mazanec]

I believe this is the number floated by Guy McPherson a while back as what absolutely will happen, based on the very highest end of a range from an early study that has since been superseded by many other studies that show much lower likely effects.

Others here can probably dig up the specific relevant studies for you

I thought that was Sam Carana on Arctic News who pushed that number.

[wili]

You may be right, or it may be both. My brain and its long term memory banks are not getting any younger.

[Wherestheice]

Well there have been multiple studies that show a 35% reduction in industrial activity could lead to a 1 C temperature rise. Guy and Sam both conclude that we are about 1.7 C above the 1750 baseline. But even if we are only 1.2 C warmer, the loss of aerosols is something to be concerned about

[vox_mundi]

Coronavirus: Nasa Images Show China Pollution Clear Amid Slowdown
https://www.bbc.com/news/world-asia-51691967



Satellite images have shown a dramatic decline in pollution levels over China, which is "at least partly" due to an economic slowdown prompted by the coronavirus, US space agency Nasa says.

Nasa maps show falling levels of nitrogen dioxide this year.

It comes amid record declines in China's factory activity as manufacturers stop work in a bid to contain coronavirus.



Nasa scientists said the reduction in levels of nitrogen dioxide - a noxious gas emitted by motor vehicles and industrial facilities - was first apparent near the source of the outbreak in Wuhan city but then spread across the country.

Nasa compared the first two months of 2019 with the same period this year.

The space agency noted that the decline in air pollution levels coincided with restriction imposed on transportation and business activities, and as millions of people went into quarantine.

"This is the first time I have seen such a dramatic drop-off over such a wide area for a specific event," Fei Liu, an air quality researcher at Nasa's Goddard Space Flight Center, said in a statement.

She added that she had observed a decline in nitrogen dioxide levels during the economic recession in 2008, but said that decrease was more gradual.

Nasa noted that China's Lunar New Year celebrations in late January and early February have been linked to decreases in pollution levels in the past. But it said they normally increase once the celebrations are over.

"This year, the reduction rate is more significant than in past years and it has lasted longer," Ms Liu said.

"I am not surprised because many cities nationwide have taken measures to minimise spread of the virus."

[interstitial]

I suspect the effect is still dramatic but I wish they would use the same number of days for a more accurate comparison. This approach just leaves me wondering.

[Zinc_wit]

Took this from Beckwiths twitter,Any thoughts on this?

The Coronavirus has shuttered about 25% of Chinese industrial production for weeks on end. Since Chinese production and industrial activist accounts for about 1/4 of global production, 1/4 x 1/4 = 1/16 or about 6% of global production has been halted. Thus, my back of the envelope best guess has global CO2 emissions down about 6%, and globally produced aerosols down about 6% as well.

Since global dimming from aerosols is thought to be between 0.25 to 1.1 C, if we take the 1 C number as an upper limit, then the Coronavirus has resulted in global warming of about 0.06 C; with regional warming over China of about 0.25 C.

Also I was wondering if anyone could help me make sense of this quote?
It's not related to Beckwiths qoute, just something I found.
I lurk on this forum but I can still make little sense out of most what is said, I'm pretty new to it all haha.

Use CAMS and look at the SO2 levels. They are the primary drivers of global dimming. The SO2 emissions only dropped off the cliff on the 24th. It’s about a 6 week cycle for the advection of SO2 from the troposphere into the stratosphere to hydrate and precipitate out. So we have about till the end of the month for the big hit. According to the latest papers on the matter this should be a .5-1c rise given that about 30% of SO2 emissions are gone. Jet contrails are the second anthropomorphic cause of global dimming and have a much more immediate effect so we should see the effects of that in a one week trailing average starting at the end on the lunar new year holiday.

[Juan C. García]

Took this from Beckwiths twitter,Any thoughts on this?

The Coronavirus has shuttered about 25% of Chinese industrial production for weeks on end. Since Chinese production and industrial activist accounts for about 1/4 of global production, 1/4 x 1/4 = 1/16 or about 6% of global production has been halted. Thus, my back of the envelope best guess has global CO2 emissions down about 6%, and globally produced aerosols down about 6% as well.

Since global dimming from aerosols is thought to be between 0.25 to 1.1 C, if we take the 1 C number as an upper limit, then the Coronavirus has resulted in global warming of about 0.06 C; with regional warming over China of about 0.25 C.

There is a chain reaction when there is a reduction in production, like the one that happened in China. If one of the factories (that stopped) makes car parts that are necessary on an specific car brand, it stops or reduces the production of that car brand. so factories all around the world start to recieve less requests to produce other parts for the same car brand.

So, a 25% production reduction in China could make another 3% production reduction worldwide (I am just guessing the worldwide impact, but there has to be some). 6% worldwide industrial slowdown will be the minimum.

CO2 and aerosols emissions are made by different activities, so a 6%+ industrial reduction worldwide, doesn't mean a reduction of 6%+ CO2 and/or aerosols emissions.

[blumenkraft]

Use CAMS and look at the SO2 levels. ...

They are referring to this chart >> https://atmosphere.copernicus.eu/charts/cams/sulphur-dioxide-forecasts?time=2020030100,3,2020030103&projection=classical_arctic&layer_name=composition_so2_totalcolumn&facets=Family,Reactive%20gases

I would say it is way too early to make any assumptions. The logic is correct though, fewer SO2 means a lower masking effect, which could lead to higher mean temperatures.

I guess we have to wait until there are actual studies on the topic.

[Zinc_wit]

CO2 and aerosols emissions are made by different activities, so a 6%+ industrial reduction worldwide, doesn't mean a reduction of 6%+ CO2 and/or aerosols emissions.

Would it mean his math is flawed then and it should be revisited?
I wonder if its possible to find the exact amount of reduction in CO2/aerosol emissions caused by the 6% industrial reduction. Thank you for your response!

They are referring to this chart >> https://atmosphere.copernicus.eu/charts/cams/sulphur-dioxide-forecasts?time=2020030100,3,2020030103&projection=classical_arctic&layer_name=composition_so2_totalcolumn&facets=Family,Reactive%20gases

I would say it is way too early to make any assumptions. The logic is correct though, fewer SO2 means a lower masking effect, which could lead to higher mean temperatures.

I guess we have to wait until there are actual studies on the topic.

Thank you for the link, makes a bit more sense now.
Hopefully there will be some studies soon, I keep wondering if the effects of this are going to be severe, I suppose only time will tell!

[blumenkraft]

You are welcome, Zinc_wit.

My best guess is that the recession has only begun and that there will be measurable effects.

But again, this can only be assessed in hindsight. Next year this time we definitely know a lot more.

[oren]

0.06C is possible, 0.5-1C global is IMHO impossible in the short term, the second math sounds bogus. 30% of SO2 won't result in such numbers.

[KiwiGriff]

[Tor Bejnar]

Cross post:  Covid-19 may be having a noticeable affect on Climate Change, already.

The following GISS anomaly data and the attached image from the linked Nick Stokes website indicates that the NCEP/NCAR anomaly for February 2020 was slightly higher than that for January 2020, which may be a record for the month of February.  As this high anomaly occurred in a non-El Nino season, this makes suspect that reduced aerosol emissions from shipping and from China may be contributing to the high anomalies for both January, and February, 2020:

http://www.moyhu.org.s3.amazonaws.com/data/freq/ncep.html

Last 12 months averages
See below for GISS, NOAA
Year   Month   Anomaly
2020   Feb          0.554
2020   Jan          0.552
2019   Dec          0.587
2019   Nov          0.408
2019   Oct          0.475
2019   Sep          0.419

see original for graphic

[longwalks1]

I did look to see if Dr. Tim Garrett had posted anything lately about this, one tweet. He sees a minimal effect in his tweet.   He is primarily looking at aerosols and physics of clouds.   

  Dated but a good
https://earthjustice.org/sites/default/files/black-carbon/amap-quinn-et-al-2008.pdf

Arctic Monitoring and Assessment Programme (AMAP), P.O. Box 8100 Dep, N-0032 Oslo, NorwayCitation: AMAP / Quinn et al., 2008. The Impact of Short-Lived Pollutants on Arctic Climate.  AMAP Technical Report No. 1 (2008), Arctic Monitoring and Assessment Programme (AMAP), Oslo, Norway.(available as an electronic document from www.amap.no) Authors: P.K. Quinn1, T.S. Bates1, E. Baum2, T. Bond3, J.F. Burkhart4, A.M. Fiore5, M. Flanner6, T.J. Garrett7, D. Koch8, J. McConnell9, D. Shindell8, and A. Stohl4

Nice graphics

[FrostKing70]

How quickly would the effect be visible / measurable if aerosols drop (the first post, above, indicates weeks to months)?   Is this a possible impact from the Covid-19 lock downs / reduced pollution? 

[TerryM]

^^
I'd expect a change in aerosols would be noticeable in 24 hours or less. Smog certainly rolled into Riverside California within hours of the morning rush hour in Los Angeles, perhaps 60 miles away.


I can't imagine that the lockdown hasn't had an affect on aerosol levels.
Terry

[VaughnAn]

I am also wondering if there are any direct measurements showing sun transmittance at locations where measurements have previously been acquired over longer periods of time. By comparing new data to older data it would seem to me to be useful to determine how much more light is reaching the surface.  A sudden increase in temperatures would be strong evidence to quantify some of these changes as well.  One thing I noticed is that the sky appears to be a lighter shade of blue near the horizon from my location.

I looked at the "Science of Aerosols thread and upthread here and saw the calculated temperature predictions of reduced aerosols and there appears to a fair spread in estimates.  I was really looking for new hard data and I may have missed it. 

Also, as close as wet bulb temperatures came to briefly being unsurvivable in Pakistan last year any increase in wet bulb temperatures could be disastrous.  Hmm.

[Niall Dollard]

Data from the UKMO shows that UK has already had sunniest April on record.

[vox_mundi]

Spring 2020 Could Even Break Summer Sun Records
https://phys.org/news/2020-05-summer-sun.html

This year's 'lockdown spring' is likely to be the sunniest on record in parts of the UK, and may even rank among the sunniest seasons ever recorded—including all the summers.

Sunshine data from the University of Reading's weather observatory show that, as at 10am on 20 May, there had already been more than 610 hours of sunshine since the start of March—with more than a week of May still to go. This beats the 604.6 hours in 1990, which was the previous highest spring total since the University's sunshine records began in 1956.

Remarkably, the amount of sunshine this spring is also almost certain to beat many of the summers in the record, despite spring having significantly fewer hours of daylight. As a percentage of the day length, it may rank in the top five sunniest seasons ever in Reading.

In April, 60.3% of the daylight hours in Reading were sunny, reaching a total of 250.9 hours of sunshine for the month and making it the sunniest April recorded there. Only four other months on the University's records have ever surpassed 60%, and these all occurred between May and August.

In terms of the percentage of possible sunshine, the sunniest month in its record is August 1976 with 62%. The sunniest month in terms of total hours of sunshine was June 1975, with 305.6 hours.

[be cause]

Here in N. Ireland , as we have lost our daily mess in the air of hundreds of cross-Atlantic flights it is obvious that their absence has helped . The sun often faded out behind trails left by flights hours before sunset . This year sun is getting to set below the horizon .
  I would suggest the dominance of anticyclonic dry weather has much more effect on total hours sun this spring but I am enjoying the break from planes overhead and the local positive effects .. b.c.

[ArcticMelt2]

Spring 2020 Could Even Break Summer Sun Records
https://phys.org/news/2020-05-summer-sun.html

This year's 'lockdown spring' is likely to be the sunniest on record in parts of the UK, and may even rank among the sunniest seasons ever recorded—including all the summers.

Sunshine data from the University of Reading's weather observatory show that, as at 10am on 20 May, there had already been more than 610 hours of sunshine since the start of March—with more than a week of May still to go. This beats the 604.6 hours in 1990, which was the previous highest spring total since the University's sunshine records began in 1956.

Remarkably, the amount of sunshine this spring is also almost certain to beat many of the summers in the record, despite spring having significantly fewer hours of daylight. As a percentage of the day length, it may rank in the top five sunniest seasons ever in Reading.

In April, 60.3% of the daylight hours in Reading were sunny, reaching a total of 250.9 hours of sunshine for the month and making it the sunniest April recorded there. Only four other months on the University's records have ever surpassed 60%, and these all occurred between May and August.

In terms of the percentage of possible sunshine, the sunniest month in its record is August 1976 with 62%. The sunniest month in terms of total hours of sunshine was June 1975, with 305.6 hours.

I read that in Germany a similar situation.

https://www.cleanenergywire.org/news/2020-germany-saw-sunniest-april-records-began

In 2020, Germany saw sunniest April since records began

This month was the sunniest and third-driest April in Germany since records began in 1881, the country's National Meteorological Service (DWD) said in a press release.

https://www.dwd.de/DE/presse/pressemitteilungen/DE/2020/20200429_deutschlandwetter_april2020_news.html

April has the most sunshine since records began in 1951
In 2020, April triumphed with an exceptional amount of sunshine: with around 294 hours, it reached around 190 percent of the target of 154 hours. That was slightly more than in the previous record April 2007 with 289 hours. The sun was the longest north of Munich at around 325 hours. Since March 13, the hours of sunshine there have even totaled around 500 hours.

[glennbuck]

Zack's plot also shows just how anomalous May through July was. Here is 70-90N 925Mb temps for the same span of months over the years

Maybe the reduced aerosol masking effect is starting to come through in the data.

[blumenkraft]

But there was also an unprecedentedly high amount of Arctic wildfires. So there were aerosols.

[glennbuck]

But there was also an unprecedentedly high amount of Arctic wildfires. So there were aerosols.

Maybe 10% factor the Arctic wildfires but the reduction in Industrial activity was reduced by 20% Globally for 3 months. The USA had a second quarter GDP drop of 32.9%, flights are still running internationally at more than half the pre-covid period in August. Reduced Aerosol masking effect is ongoing.

[blumenkraft]

Yeah, but what is that in absolute numbers (i.e. Gigatones)?

[glennbuck]

Yeah, but what is that in absolute numbers (i.e. Gigatones)?

A lot someone can work it out for the globe maybe, an example i have is Australia Bushfires was 50% of there yearly CO 2 released and 14% of there forests destroyed in one season.

Australian CO2 emissions have surged by 250 million tonnes as a result of bushfires in New South Wales and Queensland.

https://www.weforum.org/agenda/2019/12/australia-bushfires-co2-emissions-climate-change/

The reduction in SO2 would maybe be more of a problem.

Volcanoes emit sulfur dioxide (SO2) into the upper atmosphere, known as the stratosphere. This is above the troposphere where weather actually happens. This impact can last several years unlike industrial aerosol sources which go into the troposphere and are rained out typically in less than a week.

[oren]

Zack's plot also shows just how anomalous May through July was. Here is 70-90N 925Mb temps for the same span of months over the years

Maybe the reduced aerosol masking effect is starting to come through in the data.

Would there be any physical reason for the effect to only be seen in the high Arctic and in 925Mb temps? If not, signal should be seen in other regions and for different elevations.

[glennbuck]

Would there be any physical reason for the effect to only be seen in the high Arctic and in 925Mb temps? If not, signal should be seen in other regions and for different elevations.

Perhaps the reduction in Russia of Oil, Gas and coal production due to the fallout of reduced demand globally would have a larger effect on the region of Siberia and the Arctic first from the reduction in the aerosol masking effect.

Other countries that do not produce Oil and Gas and mainly run on a service economy with low manufacturing output, would have a lower regional effect in the short term. Would the effect be more noticeable in the short term in places like the Arctic that is warming twice as fast as other parts of the globe.

[kassy]

Or the anomaly in the graph is the result of ongoing changes like deteriorating land snow cover around there etc.

[bluice]

Maybe it’s just the background warming? I’m pretty confident summer 2021 will bring us another record breaking NH heat wave, aerosol reduction or not.

Just like 2019 in Western Europe, 2018 in Scandinavia etc etc...

[Hefaistos]

I think it's called "weather".
July was a different story than June.
Meanwhile, temperature anomalies keep going down, in both NH and SH.

[glennbuck]

I think it's called "weather".
July was a different story than June.
Meanwhile, temperature anomalies keep going down, in both NH and SH.

Many records broke this year without an El Nino like we had in 2016.

Averaged as a whole, the January–June 2020 global land and ocean surface temperature was 1.07°C (1.93°F) above the 20th century average of 13.5°C (56.3°F). This was only 0.05°C (0.09°F) shy of tying the record warm January–June of 2016. According to a statistical analysis done by NCEI scientists, the year 2020 is very likely to rank among the five warmest years on record.

https://www.ncdc.noaa.gov/sotc/global/202006

[anthropocene]

I think it's called "weather".
July was a different story than June.
Meanwhile, temperature anomalies keep going down, in both NH and SH.

NCEP reanalysis is obviously broken.
Copernicus, NOAA and all other global temperature measurements I've seen disagree with the decrease in temperatures shown by NCEP. (With decreasing pacific sea surface temperatures I expect temperatures to decrease (slowly) for the rest of the year).
Please stop posting cherry picked data which matches your pre-judged position. For example the average of the last 12-months is close to a record: See: https://climate.copernicus.eu/surface-air-temperature-june-2020

[Hefaistos]

I think it's called "weather".
July was a different story than June.
Meanwhile, temperature anomalies keep going down, in both NH and SH.

NCEP reanalysis is obviously broken.
Copernicus, NOAA and all other global temperature measurements I've seen disagree with the decrease in temperatures shown by NCEP. (With decreasing pacific sea surface temperatures I expect temperatures to decrease (slowly) for the rest of the year).
Please stop posting cherry picked data which matches your pre-judged position. For example the average of the last 12-months is close to a record: See: https://climate.copernicus.eu/surface-air-temperature-june-2020

Maybe you should ask Karsten Haustein this question?

NCEP is not "obviously broken". It's a reanalysis, i.e. a model. It might have some issues with some specific areas but no-one has shown in what way it would be broken! Please be more specific, if you have some evidence for your claim.

Most temperature anomalies' series show the same picture, here you can compare some of them with NCEP. But maybe HadCrut and all the rest are also "broken" and "cherry picked"?:

[anthropocene]

Copernicus is in for July 2020.
https://climate.copernicus.eu/surface-air-temperature-july-2020

"Global temperatures were much above average in July 2020. The month was:

    0.49°C warmer than the 1981-2020 average for July;
    the third warmest July in this data record;
    cooler by 0.07°C than July 2019, the warmest July;
    cooler by 0.04°C than July 2016, the second warmest July."

What differences from July 2019 and July 2016 does NCEP record? I make it: -0.14degC cooler than 2019 and -0.2degC. cooler than 2016 (https://moyhu.blogspot.com/p/latest-ice-and-temperature-data.html#NCAR). I can't be sure whether these are the same as the data that you post because no links were provided.

Anyway - the thread topic is discussing what masking effect aerosols may have on continuously increasing temperatures from AGW. Why would you use model reanalysis numbers to base the discussion on when real world physical temperature measurements are available (if you can wait a few days for the collation for monthly figures to be published)?

So temperatures in the first half of 2020 have been almost record breaking with only slightly positive ENSO numbers. So there could be a signature of less aerosols due to covid-19 causing a temperature increase but the evidence is by no means compelling. I'm willing to be convinced either way - if somebody can provide real evidence to support their theory.

[kassy]

Here an article explaining why we won´t see the effect:

They found that the drop off peaked in April, with CO2, nitrogen oxides and other emissions falling between 10-30% globally, mainly due to declines in surface transport.

But this new work shows that some of the declines in greenhouse gases actually cancelled each other out in terms of warming.

Nitrogen oxides from transport normally have a warming impact in the atmosphere.

While they went down by 30%, they were matched by a drop in sulphur dioxide, which mainly comes from the burning of coal.

https://www.bbc.com/news/science-environment-53681096

Since we knew that there was a change in shipping fuels from this year there will be some scientists gathering data on that. All the effect would be more local and close to certain busy shipping lanes but that will at least tell us something.

[El Cid]

But this new work shows that some of the declines in greenhouse gases actually cancelled each other out in terms of warming.

Nitrogen oxides from transport normally have a warming impact in the atmosphere.

While they went down by 30%, they were matched by a drop in sulphur dioxide, which mainly comes from the burning of coal.

Exactly! That is why we did not see much effect on temperatures.

[El Cid]

. Why would you use model reanalysis numbers to base the discussion on when real world physical temperature measurements are available (if you can wait a few days for the collation for monthly figures to be published)?

. I'm willing to be convinced either way - if somebody can provide real evidence to support their theory.

I analysed temperatures upthread, comparing the months of 2020 to 2019. You could NOT see any effect in the March-May period.
January and February are suspect though, and that may be down to the new IMO2020 (shipping) rules that drastically reduced So2 emissions by ships

[glennbuck]

But volcanic gases like sulfur dioxide can cause global cooling, while volcanic carbon dioxide, a greenhouse gas, has the potential to promote global warming.

SO2 causes Global cooling, a reduction would therefore cause global warming.

[kassy]

Yes so if you would be really boring you could just add it to things making AGW worse assuming our current plan is to eliminate them. The interesting thing is to figure out how much they matter.

We have seen many threads and mentions about maybe seeing the covid signal directly but this pretty much proves we don´t.

I am just going to wait for the shipping related stuff.