Drats! Down the warmhole the warming went

From the Harvard School of Engineering and Applied Sciences

“Warming hole” delayed climate change over eastern United States

April 26, 2012

50-year model suggests regional pollution obscured a global trend

CONTACT: Caroline Perry, (617) 496-1351

Cambridge, Mass. – April 26, 2012 – Climate scientists at the Harvard School of Engineering and Applied Sciences (SEAS) have discovered that particulate pollution in the late 20th century created a “warming hole” over the eastern United States—that is, a cold patch where the effects of global warming were temporarily obscured.

While greenhouse gases like carbon dioxide and methane warm the Earth’s surface, tiny particles in the air can have the reverse effect on regional scales.

“What we’ve shown is that particulate pollution over the eastern United States has delayed the warming that we would expect to see from increasing greenhouse gases,” says lead author Eric Leibensperger (Ph.D. ’11), who completed the work as a graduate student in applied physics at SEAS.

“For the sake of protecting human health and reducing acid rain, we’ve now cut the emissions that lead to particulate pollution,” he adds, “but these cuts have caused the greenhouse warming in this region to ramp up to match the global trend.”

At this point, most of the “catch-up” warming has already occurred.

The findings, published in the journal Atmospheric Chemistry and Physics, present a more complete picture of the processes that affect regional climate change. The work also carries significant implications for the future climate of industrial nations, like China, that have not yet implemented air quality regulations to the same extent as the United States.


Change in surface temperature 1930-1990

Observed change in surface air temperature between 1930 and 1990. Observations are from the NASA GISS Surface Temperature Analysis. Image courtesy of Eric Leibensperger.


Until the United States passed the Clean Air Act in 1970 and strengthened it in 1990, particulate pollution hung thick over the central and eastern states. Most of these particles in the atmosphere were made of sulfate, originating as sulfur emissions from coal-fired power plants. Compared to greenhouse gases, particulate pollution has a very short lifetime (about 1 week), so its distribution over the Earth is uneven.

“The primary driver of the warming hole is the aerosol pollution—these small particles,” says Leibensperger. “What they do is reflect incoming sunlight, so we see a cooling effect at the surface.”

This effect has been known for some time, but the new analysis demonstrates the strong impact that decreases in particulate pollution can have on regional climate.

"Warming hole" delayed climate change over eastern United States

The researchers found that interactions between clouds and particles amplified the cooling. Particles of pollution can act as nucleation sites for cloud droplets, which can in turn reflect even more sunlight than the particles would individually, leading to greater cooling at the surface.

The researchers’ analysis is based on a combination of two complex models of Earth systems. The pollution data comes from the GEOS-Chem model, which was first developed at Harvard and, through a series of many updates, has since become an international standard for modeling pollution over time. The climate data comes from the general circulation model developed by NASA’s Goddard Institute for Space Studies. Both models are rooted in decades’ worth of observational data.

Since the early 20th century, global mean temperatures have risen—by approximately 0.8 degrees Celsius from 1906 to 2005—but in the U.S. “warming hole,” temperatures decreased by as much as 1 degree Celsius during the period 1930–1990. U.S. particulate pollution peaked in 1980 and has since been reduced by about half. By 2010 the average cooling effect over the East had fallen to just 0.3 degrees Celsius.

“Such a large fraction of the sulfate has already been removed that we don’t have much more warming coming along due to further controls on sulfur emissions in the future,” says principal investigator Daniel Jacob, the Vasco McCoy Family Professor of Atmospheric Chemistry and Environmental Engineering at SEAS.

Jacob is also a Professor of Earth and Planetary Sciences at Harvard and a faculty associate of the Harvard University Center for the Environment.

Besides confirming that particulate pollution plays a large role in affecting U.S. regional climate, the research emphasizes the importance of accounting for the climate impacts of particulates in future air quality policies.

“Something similar could happen in China, which is just beginning to tighten up its pollution standards,” says co-author Loretta J. Mickley, a Senior Research Fellow in atmospheric chemistry at SEAS. “China could see significant climate change due to declining levels of particulate pollutants.”

Sulfates are harmful to human health and can also cause acid rain, which damages ecosystems and erodes buildings.

“No one is suggesting that we should stop improving air quality, but it’s important to understand the consequences. Clearing the air could lead to regional warming,” Mickley says.

Leibensperger, Jacob, and Mickley were joined by co-authors Wei-Ting Chen and John H. Seinfeld (California Institute of Technology); Athanasios Nenes (Georgia Institute of Technology); Peter J. Adams (Carnegie Mellon University); David G. Streets (Argonne National Laboratory); Naresh Kumar (Electric Power Research Institute); and David Rind (NASA Goddard Institute for Space Studies).

The research was supported by the Electric Power Research Institute (EPRI) and the U.S. Environmental Protection Agency (EPA); neither EPRI nor the EPA has officially endorsed the results. The work also benefited from resources provided by Academic Computing Services at SEAS.

Advertisements

  Subscribe  
newest oldest most voted
Notify of
TDBraun

There’s a hole in their models all right.

This should be good for a juicy grant.

temp

This is interesting in basically they are saying global cooling was/is real and the recent warming is the result/mostly the result of actions taken to fight global cooling and thus meaning that global warming is wrong…
Should be interesting how the info is spun at least.

DocMartyn

The temperature changes of the US do not support this hypothesis at all, The sulphates were dropped from the 50’s to the 70’s and then again in the mid-80’s. There has been almost no warming since the 90’s.

Another model study based on speculation.

GeoLurking

DocMartyn points out a really glaring problem.
Additionally, “At this point, most of the “catch-up” warming has already occurred.” doesn’t fare very well when you note all the data manipulation of the historical record.
“Already occurred” how? By tweaking the data points? Or is that from unadulterated info?
Garbage In => Garbage Out.

John West

“Fig. 9. 1950–2050 trends in annual mean surface air temperatures over the mid-Atlantic US (boxed region in Fig. 2). Observa- tions (GISTEMP) are compared to the control simulation including greenhouse and aerosol forcings and to the sensitivity simulation with no US anthropogenic aerosols.”
A control simulation!

Chuck Wiese

This is a bunch of hooey and BS. The “regional cooling” extended to the entire 48 lower US according to NCDC records, and the trend for the entire US was down -.74F/.41C using the thirty year mean starting in 1981, with the period of record being 2001 to 2011. This trend is also negative using a 100 year mean.
How believable is it that over the entire year that aerosols, especially in very unpopulated areas would be causing a downward trend in temperature with the amount of wind and convection that would cover all areas? This just isn’t.credible.
Perhaps the good professor needs to look at the way he and his colleagues calculate radiative forcing. In the presence of water vapor and a hydrological cycle it is absurd to only look at what infrared was absorbed at the particular wavenumber that corresponds to the concentration increases of constituents like CO2. The spectrally integrated outgoing longwave radiation is the only relevant comparison of an absorbing constituent to determine if anything has actually changed in the OLR, and if these guys actually took the time to try and determine this, I would bet there would be the big boogey man of truth waiting for them to confirm to them that CO2 and the other GHG’s are not causing the climate to change or reducing the OLR.

Jason

Nothing about this makes any sense.

Nope!
From 1930 to 1980 the “Ohio Valley Region” cooled at a rate of -0.44 degF / Decade.
From 1980 to 1998 the “Ohio Valley Region” warmed at a rate of 0.33 degF / Decade.
From 1998 to 2010 the “Ohio Valley Region” cooled at a rate of -1.23 degF / Decade.
Oh oh …. that ruins this theory, unless they think aerosols increased by a massive amount after 1998.
http://www.ncdc.noaa.gov/oa/climate/research/cag3/ce.html

I never thought I’d say it, but I’m getting sick of models.
Pointman

Nerd

I am all for clean air. One thing that most people do not realize is heavy air pollution can block UVB sunlight that we need to produce vitamin D in the skin. Vitamin D is very important to controlling or preventing asthma. They saw the dirty air causes asthma but apparently they never made the connection between asthma and vitamin D deficiency. EPA claims that dirty air pollution directly causes asthma but it’s not so simple…

Todd

Making it up as they go along.

Merovign

Friday: The reason it’s so hot is because of AGW!
Monday: The reason it wasn’t so hot when we said it was is because of AGW!

GlynnMhor

“The pollution data comes from the GEOS-Chem model,.. The climate data comes from the general circulation model…”
It’s not actually ‘data’ if it’s just the results of a model.

Willis Eschenbach

So their claim is that the temperature drop in northern Mexico, and New Mexico, is because of aerosols?
Egads … usually it’s models all the way down, but this seems to be blind folks all the way down.
w.

Sean

Anything that has the Goddard Institute for Climate Propaganda involved in it can be dismissed out of hand as junk science.

P. Solar

Looks like another attempt to explain away natural cycle in climate.
Next we will hear that this is applied to Europe as well and the naughty particles just tricked scientists into making exaggerated estimates of AGW , fooled by the reduced air pollution.
From Jevrejeve 2008 examining sea level change rate.
http://i40.tinypic.com/nx3q1.png
The cycles have been diminishing in amplitude since 1800. That could be linked tenuously to increasing GHG (including water vapour) dampening variation.
don’t see it spring back since 1990.

juanslayton

I’m relieved to know that the notorious air pollution we experienced in the 40s and 50s had no effect on our regional temperature. Perhaps it was really just an urban myth…
John in Southern Cal

RHS

I thought the premise of Climate Change was regional pollution.

Peter

“The researchers’ analysis is based on a combination of two complex models of Earth systems.”
So let’s see here; a model is used to explain why warming predicted by a second model has not occurred.
There’s a classic quote that can be used to explain what’s going on here.
“Its models all the way down”

M Hastings

I noticed the mention of acid rain in the article and I needed to point out something.
I live in AZ. and have had swimming pools for 16 years of different shapes and sizes. It doesn’t rain much in AZ so its a noticeable event. Everytime it rains (for the last 16 years) I must ADD ACID to my swimming pools in order to lower the PH to the recommended level of 7-7.5. Today it rained again and because I read this article and was curious I took the PH of the rain puddles on my deck and walkways and in the garden, all three puddles had a PH of 7.8 or higher.
I looked up PH of rain on the internet and all the articles I read listed it as around 5.5 or lower, this does not jive with my 16 years of experience with swimming pools and adding acid. I would be curious if anyone else has noticed similar results.

Gail Combs

Nerd says:
April 26, 2012 at 4:43 pm
I am all for clean air…..
__________________________
All of us are for clean air and not fouling our own nest. However CO2 is a plant fertilizer and thank goodness we are returning the CO2 that was locked up back into the biosphere. The plants love it.

“but in the U.S. “warming hole,” temperatures decreased by as much as 1 degree Celsius during the period 1930–1990. ”
Wait a minute. Aren’t they being dishonest by claiming the cooling stopped in 1990 when it stopped in 1980 and started again in 1998 — at least in the NOAA OHIO VALLEY REGION?
They are desperate to link up the warming with the 1990 extension of the clean air act.
“Ignore the pea up my sleeve … tell me which cup it is under.”

P. Solar

“The researchers found that interactions between clouds and particles amplified the cooling. Particles of pollution can act as nucleation sites for cloud droplets, which can in turn reflect even more sunlight than the particles would individually, leading to greater cooling at the surface.”
Interesting, so Svenmark’s cosmic ray nucleation would presumably have a similar effect.

I suspect the real sulfuric acid aerosols have not declined as much as is postulated and the plume is located over the mid Atlantic states downwind of most of the power plants that are still burning high sulfur coal. Some power plants with scrubbers are actually producing “blue mist” sulfuric acid that hangs in the atmosphere longer than SO2. We in North Carolina are still getting it from TVA. Is there even a network for measuring sulfuric acid arosols that can be used to check the model?

PaulH

It’s good to know that the science is settled.
/snark

Goldie

Without doing heaps of analysis: the first thing they do is presume warming should be there when it isn’t – why do they do this…..because a model says it should be there. They then use a different model to explain why the results of the first model were wrong. Lets just assume that they are right about this – so how does that translate to (say) the problem that the antarctic or indeed southern hemisphere is not warming as much as the arctic/northern hemisphere? Generally One might assume that this was occurring because of increased anthropogenic emissions in the Northern Hemisphere. But..then that would give the opposite effect of the one they postulate.

Gail Combs

GlynnMhor says:
April 26, 2012 at 4:50 pm
“The pollution data comes from the GEOS-Chem model,.. The climate data comes from the general circulation model…”
It’s not actually ‘data’ if it’s just the results of a model.
__________________________
OH, My Goodness no, Didn’t you see what they said?

The pollution data comes from the GEOS-Chem model, which was first developed at Harvard and, through a series of many updates, has since become an international standard for modeling pollution over time. The climate data comes from the general circulation model developed by NASA’s Goddard Institute for Space Studies. Both models are rooted in decades’ worth of observational data.

They are talking about observational data like this: Hansen’s temp graphs 1999, 2001, & 2008

Pamela Gray

Where to begin. Buy whatever journal this was published in and use it to line your bird cage.

P. Solar

“The researchers found that interactions between clouds and particles amplified the cooling. Particles of pollution can act as nucleation sites for cloud droplets, which can in turn reflect even more sunlight than the particles would individually, leading to greater cooling at the surface.
The researchers’ analysis is based on a combination of two complex models of Earth systems… The climate data comes from the general circulation model developed by NASA’s Goddard Institute for Space Studies. ”
So it was not “climate data ” at all. It was model output data. What “the researchers found” was what was programmed into the model. That hardly a scientific discovery , they could have asked to look at the code.

Werner Brozek

“No one is suggesting that we should stop improving air quality, but it’s important to understand the consequences. Clearing the air could lead to regional warming,”
So is he suggesting both are evil, but one is the lesser of the two evils?

Rob Crawford

Gail, they may have “rooted” their models in data, but they’re still running models.

Sherlock

Epicycles… they finally have gotten to epicycles. This should just get better and better. Popcorn futures, folks!

Mydogsgotnonose

Unfortunately, the aerosol optical physics in the models is wrong. Sulphate pollution reduces cloud albedo by switching off droplet coarsening. it’s the rain clouds which reflect most light.

Gail Combs

(I really wish I could post these photos)
It seems the Dust bowl of the 1930’s must have cause really frigid weather…NOT.

In 1932, 14 dust storms were recorded on the Plains. In 1933, there were 38 storms. By 1934, it was estimated that 100 million acres of farmland had lost all or most of the topsoil to the winds. By April 1935, there had been weeks of dust storms, but the cloud that appeared on the horizon that Sunday was the worst. Winds were clocked at 60 mph. Then it hit.
“The impact is like a shovelful of fine sand flung against the face,” Avis D. Carlson wrote…
Hugh Hammond Bennett, was in Washington D.C. on his way to testify before Congress about the need for soil conservation legislation. A dust storm arrived in Washington all the way from the Great Plains. As a dusty gloom spread over the nation’s capital and blotted out the sun, Bennett explained, “This, gentlemen, is what I have been talking about.”… http://www.livinghistoryfarm.org/farminginthe30s/water_02.html

I am sure the climate scientist would explain that the dust storms were only local.
Hansen’s graph of US temps: http://i31.tinypic.com/2149sg0.gif

Alvin

Shorter: Evil pollution needs to be stopped so we can see the affects of evil pollution.

DirkH

Nerd says:
April 26, 2012 at 4:43 pm
“I am all for clean air. One thing that most people do not realize is heavy air pollution can block UVB sunlight that we need to produce vitamin D in the skin. Vitamin D is very important to controlling or preventing asthma.”
Here in Germany there’s about 6 months of “polar winter”, meaning the sun does not rise up enough, its UVB rays have to penetrate too much air to actually reach the surface and get mostly deflected, so you can’t get enough of them to synthesize meaningful amounts of vitamin D. Of course in Scandinavia it’s even worse.
I guess the latitude you live at has a much bigger influence on the availability of UVB than pollution has. In the EU, sun banks don’t help; the EU commission has ordered that they have to have UVB filters. You get tanned but you get no Vitamin D. Their reason for this was that UVB also causes skin cancer.
My personal solution is Vitamin pils and fatty fish. Herring and Mackarel mostly.

lbouffard

My Personal Theory is the air pollution has been decently heavy for the past ~130ish years over the eastern US which helped keep the temps down yet it was pretty stable in its coverage so that the natural variation came into play for the temps, then in the 70’s we started to clean the air via clean air act, and the air got cleaner…thus allowing more sun to hit the planet, thus warming the planet temporarily overriding the long term natural variation in temps, bringing the planet up to the temps that were supposed to be at if their was minimal air pollution. the natural variation is now taking over as the world temp reached where it was supposed to be at with the temps fluctuating up and down in ~30 year cycles……that is my rough hypothesis, but what do i know i’m just a civil engineer 🙂

Bill Illis

The US temperature trend has been adjusted upwards by +0.612C now in the new USHCN Version 3.
One cannot go back and say the the temperatures were affected by aerosols or whatever because no one knows what the true temperature trend is.

DirkH

M Hastings says:
April 26, 2012 at 4:58 pm
“I looked up PH of rain on the internet and all the articles I read listed it as around 5.5 or lower, this does not jive with my 16 years of experience with swimming pools and adding acid. I would be curious if anyone else has noticed similar results.”
Trees cause acidic rain. No kidding. In other words, the water in forest creeks should be that acidic.
Reagan was in a way right when he said that ““trees cause more pollution than automobiles do”.
http://wattsupwiththat.com/2012/01/11/new-study-confirms-that-nature-is-responsible-for-90-of-the-earths-atmospheric-acidity/

Willis Eschenbach

The pollution data comes from the GEOS-Chem model, which was first developed at Harvard and, through a series of many updates, has since become an international standard for modeling pollution over time. The climate data comes from the general circulation model developed by NASA’s Goddard Institute for Space Studies. Both models are rooted in decades’ worth of observational data.

Whew, I feel so much better knowing that …
I don’t get it. They have data on historical temperatures. Why do they need the climate model? Seems like a bog-standard regression of the GEOS-Chem model against actual temperatures would be preferable …
w.

Gail Combs

Rob Crawford says:
April 26, 2012 at 5:12 pm
Gail, they may have “rooted” their models in data, but they’re still running models.
_______________________________________
ROb, look at the graph I included of Hansen’s temperature “Data” that this study is “based on” http://i31.tinypic.com/2149sg0.gif
(Don’t bust a gut laughing)

DesertYote

More non-sense from pseudo-scientists with their freshly minted PhD’s and their modern Marxist world view.

Gunga Din

“Cambridge, Mass. – April 26, 2012 – Climate scientists at the Harvard School of Engineering and Applied Sciences (SEAS) have discovered that particulate pollution in the late 20th century created a “warming hole” over the eastern United States—that is, a cold patch where the effects of global warming were temporarily obscured.”
I’m confused.
CO2 is pollution that causes AGW and particulates are pollution that stops it. ???
And, if they’re right, shouldn’t they call it a “cooling hole”? Or does saying something is cooling throw a wet blanket on all the warming rhetoric?

Bob in Castlemaine

Really…….surely it’s just a case of ground control to Major Leibensperger?

erik sloneker

I’ve been fond of saying that “nothing is as dangerous to our economy, our liberties and our lifestyles as a Harvard educated lawyer or a Harvard educated economist”. Looks like I’ll need to add Harvard educated scientist to that list as well.

M Hastings says:
“I live in AZ. and have had swimming pools for 16 years of different shapes and sizes. It doesn’t rain much in AZ so its a noticeable event. Everytime it rains (for the last 16 years) I must ADD ACID to my swimming pools in order to lower the PH to the recommended level of 7-7.5. Today it rained again and because I read this article and was curious I took the PH of the rain puddles on my deck and walkways and in the garden, all three puddles had a PH of 7.8 or higher.
I looked up PH of rain on the internet and all the articles I read listed it as around 5.5 or lower, this does not jive with my 16 years of experience with swimming pools and adding acid. I would be curious if anyone else has noticed similar results.”
AZ is a dry dusty place most of the time. Clean rain normally has a pH of around 5.5 because it is in equilibrium with the atmospheric concentration of CO2. The dust in AZ raises the pH to what you observe. Concrete also does it. Western coal is low sulfur and I don’t think you are getting any sulfuric acid aerosol from over the mountains to your west.

Gail Combs

Willis Eschenbach says:
April 26, 2012 at 5:25 pm

The pollution data comes from the GEOS-Chem model, which was first developed at Harvard and, through a series of many updates, has since become an international standard for modeling pollution over time. The climate data comes from the general circulation model developed by NASA’s Goddard Institute for Space Studies. Both models are rooted in decades’ worth of observational data.

Whew, I feel so much better knowing that …
_______________________________________
Willis, I find it very interesting that they would put in the sentence “Both models are rooted in decades’ worth of observational data.”
I guess they must have noticed “Deniers” have been laughing at any studies based on models as “Data” Perhaps a tiny step in the correct direction. Of course using models with well massaged and pureed data is still laughable even if the model is supposedly “rooted in decades’ worth of observational data.”