More aerosols, means more clouds, which means cooler temperatures. Now that we are cleaning up aerosols worldwide, this may explain why the Earth is getting slightly warmer – more sunlight reaches the surface
A paper published today in Science claims the transition from “pristine” to “slightly polluted” atmosphere at the beginning of the industrial revolution in the 18th century had a “dramatic aerosol effect [of increasing] clouds” over the oceans. According to the authors,
“transition from pristine to slightly polluted atmosphere yields estimated negative forcing of ~15 watts per square meter (cooling), suggesting that a substantial part of this anthropogenic forcing over the oceans occurred at the beginning of the industrial era, when the marine atmosphere experienced such transformation.”
By way of comparison, the IPCC alleged change in radiative forcing from CO2 [plus alleged positive water vapor feedback] since the beginning of the industrial era is +1.8 watts per square meter*, or 8.3 times less. According to an accompanying editorial to the paper, the authors “show that even small additions of aerosol particles to clouds in the cleanest regions of Earth’s atmosphere will have a large effect on those clouds and their contribution to climate forcing.”
*Per the IPCC formula: 5.35*ln(395/280) = 1.8 W/m2 at the top of the atmosphere [or only about 1.8* (1/3.7) = 0.5 W/m2 at the surface]
h/t to The Hockey Schtick
Smith et al. in 2004 finds that sulfur based aerosols, the kind that also get emitted from volcanoes, have been increasing since 1850, but have recently leveled off since about 1975…about the time that the US Clean Air Act really started kicking in (from updates in 1970) and other industrialized countries followed suit.
1850-2000: Methods and Results” -PNNL
Their paper:
Click to access PNNL-14537.pdf
From “Just Add Aerosols“: Science 6 June 2014: Vol. 344 no. 6188 p. 1089 DOI: 10.1126/science.1255398
The more carbon dioxide and other greenhouse gases in the atmosphere, the stronger the climate warming that results. Likewise, the more aerosol particles suspended in the atmosphere, the greater the ability of these particles either to scatter sunlight back to space and cool the planet or to absorb sunlight in the atmosphere, thereby warming the atmosphere while cooling Earth’s surface. However, not all such climate forcing processes depend linearly on the concentrations of their forcing agent. The climatic effects of aerosols are complicated by their interactions with clouds (1). On page 1143 of this issue, Koren et al. (2) show that even small additions of aerosol particles to clouds in the cleanest regions of Earth’s atmosphere will have a large effect on those clouds and their contribution to climate forcing.
The paper:
From aerosol-limited to invigoration of warm convective clouds
Abstract:
Among all cloud-aerosol interactions, the invigoration effect is the most elusive. Most of the studies that do suggest this effect link it to deep convective clouds with a warm base and cold top. Here, we provide evidence from observations and numerical modeling of a dramatic aerosol effect on warm clouds. We propose that convective-cloud invigoration by aerosols can be viewed as an extension of the concept of aerosol-limited clouds, where cloud development is limited by the availability of cloud-condensation nuclei. A transition from pristine to slightly polluted atmosphere yields estimated negative forcing of ~15 watts per square meter (cooling), suggesting that a substantial part of this anthropogenic forcing over the oceans occurred at the beginning of the industrial era, when the marine atmosphere experienced such transformation.
Editors summary: Invigorating convection in warm clouds
Atmospheric aerosols—tiny airborne particles—affect the way clouds form and how they affect climate. Koren et al. investigated how the formation of warm clouds, such as those that form over the oceans, depends on pollution levels (see the Perspective by Remer). Aerosols affect cloud formation in cleaner air disproportionately more than in more polluted air. Before the widespread air pollution of the industrial era, it seems, warm convective clouds may have covered much less of the oceans than they do today.
I’m sure this will be the lead story on ABC and NBC tonight.
Oh, sure, there were never any lightning initiated forest fires until man starting burning fossil fuels, nor did any pre-industrial people ever use wood/peat fires for cooking/heating. That’s why the atmosphere was ‘pristine’ then.
Paywalled.
Anybody knows if this is another computer model study or does it have real empirical data?
Another peed reviewed paper, no doubt.
More BS…
Uh, sorry, I did not see the link to the paper.
Hey get on the bandwagon. Don’t ally’all know that whilst the EPA has no idea on what is a natural load of airborne particulates, it is man’s job to clean the atmosphere….
Absolute rubbish.
This upsets the consensus applecart, whose view is that “we can’t think of anything but CO2 to explain the rise in temperatures since the industrial revolution.” Well, here’s something else.
When will these scientists do a study that has to do with understanding natural processes rather than “Man-made” processes?
Maybe not until the man-made “green” is cut off?
Well this is one study that may support the idea that humans can influence climate but the other way round LOL
Sounds like gradual removal of aerosols during the period 1980 to
1998 was the main cause of the warming, not CO2 increases. That
was when the automobile popultion switched over from cabureters
to much cleaner electronically controlled fuel injection. Once
the changeover was more or less complete, the warming stopped,
which is where we are today.
“For every action there is an equal and opposite reaction” . (I saw that someplace many years ago–I think it was the explanation on a desk toy my father had.) In any event , it now seems to me that for every paper that “proves” something about climate science, there is a paper that comes out that disproves it (or at the very least proves exactly the opposite). Given the alphabet soup that follows the names of all of these experts, I simply have no clue as to whom to believe anymore. The saving grace is at least I know what I believe, and at this juncture my beliefs appear to be as well founded as any presented by these scientific proofs offered up on a now daily basis.
This is ONE outlier paper that may be in fact correct. It makes sense that more particulates may induce more cloud formation (ie just look at clouds formations over volcanoes) and hence, cooling.Ironically it may be that both skeptics and warmist will agree on this one, except that warmists will have to now become coolists. LOLUnfortunately the outcome will be the same the need to reduce emissions will be called upon by both parties hahaha.
If it’s warming it our fault. If it’s cooling, it’s our fault. If they cancel each other out, and there’s no change, it’s our fault.
Roy Spencer says:
June 5, 2014 at 2:47 pm
If it’s warming it our fault. If it’s cooling, it’s our fault. If they cancel each other out, and there’s no change, it’s our fault.
==============================================
There seems to be something faulty about that reasoning. 😎
Yes, everything went down the drain when we introduced the vacuum cleaner.
Richard Lyman says:
June 5, 2014 at 2:37 pm
++++++++++++++++++++++++++
Newton’s Third Law – seems applicable to many things besides physics and engineering. Like politics, law and art even.
It’s worse than we can even imagine – and the question is: Just how much can we imagine?
Smith et al. in 2004 finds that sulfur based aerosols, the kind that also get emitted from volcanoes, have been increasing since 1850, but have recently leveled off since about 1975…about the time that the US Clean Air Act really started kicking in (from updates in 1970) and other industrialized countries followed suit.
Since China is currently burning more coal than the US is now with ‘pre-Clean Air Act’ scrubbers, and we are still using more coal than the 1970’s why does this show up? Does China coal not have any sulfur?
arthur4563 says:
June 5, 2014 at 2:36 pm
Sounds like gradual removal of aerosols during the period 1980 to
1998 was the main cause of the warming, not CO2 increases. That
was when the automobile popultion switched over from cabureters
to much cleaner electronically controlled fuel injection.
Between 1976 and 1990, pretty much the entire world, excluding the communist bloc, introduced catalytic converters.
A paper published today in Science claims the transition from “pristine” to “slightly polluted” atmosphere at the beginning of the industrial revolution in the 18th century had a “dramatic aerosol effect [of increasing] clouds” over the oceans.
A common misconception. When the Industrial Revolution occurred, coal replaced charcoal as the primary industrial fuel. Manufacturing charcoal ‘cooks off’ the volatile hydrocarbons into the atmosphere where they are an important factor in cloud seeding. I’ve seen charcoal being manufactured by the traditional method and it produces prodigious amounts of white smoke. Around the start of the Industrial Revolution, aerosols and cloud seeding volatile hydrocarbons likely declined substantially. IMO causing the end of the Little Ice Age.
An excuse for the lack of warming. Ha! I don’t believe they know anything, especially before 1850, Even 1850 I am skeptical of.
@DD More says:
June 5, 2014 at 3:00 pm
China may be burning lower sulfur coal. I did some work at a local PSEG plant a couple years back. The dropped about one billion $US on some back end technology for flue gas desulferization so they could burn US coal instead of the much more expensive very low sulfur product they were getting from Indonesia. It was nasty stuff too; constantly spontaneously combusting in the pile. There was always a fire visible on the coal pile somewhere.
It may also be the case that the Chinese power plant technology is not as primitive as folks generally assume. If I was shelling out perfectly good yuan for a new power plant, I’d like to know it was squeezing out every possible kilowatt per ton of fuel that it could.
I’m with Billy Liar (June 5, 2014 at 1:05 pm) and others. Pristine – what a joke.
Some climate scientists have blamed aerosols for the current lack of warming. Is there any evidence that aerosols have increased since the 90s?