CO2 warming effect cut by 65%, climate sensitivity impossible to accurately determine

Watts Up With That? ^ | October 12, 2010 | Anthony Watts

[Ernest_at_the_Beach]

Estimated CO2 Warming Cut By 65%

Submitted by Doug L. Hoffman, Resilient Earth via ICECAP

Any competent researcher involved with the science behind climate change will admit that CO2 is far from the only influence on global climate. It has long been known that short-lived greenhouse gases and black-carbon aerosols have contributed to past climate warming. Though the IPCC and their fellow travelers have tried to place the blame for global warming on human CO2 emissions, decades of lies and erroneous predictions have discredited that notion. For anyone still clinging to the CO2 hypothesis, a short perspective article on the uncertainty surrounding climate change in Nature Geoscience has put paid to that notion. It states that not only did other factors account for 65% of the radiative forcing usually attributed to carbon dioxide, but that it is impossible to accurately determine climate sensitivity given the state of climate science.

In “Short-lived uncertainty?” Joyce E. Penner et al. note that several short-lived atmospheric pollutants – such as methane, tropospheric ozone precursors and black-carbon aerosols – contribute to atmospheric warming while others, particularly scattering aerosols, cool the climate. Figuring out exactly how great the impacts of these other forcings are can radically change the way historical climate change is interpreted. So great is the uncertainty that the IPCC’s future climate predictions, which are all based on biased assumptions about climate sensitivity, are most certainly untrustworthy. As stated in the article:

It is at present impossible to accurately determine climate sensitivity (defined as the equilibrium warming in response to a doubling of atmospheric carbon dioxide concentrations) from past records, partly because carbon dioxide and short-lived species have increased together over the industrial era. Warming over the past 100 years is consistent with high climate sensitivity to atmospheric carbon dioxide combined with a large cooling effect from short-lived aerosol pollutants, but it could equally be attributed to a low climate sensitivity coupled with a small effect from aerosols. These two possibilities lead to very different projections for future climate change.

All truthful climate researchers know these facts, yet publicly the party line is that catastrophic changes are in the offing and CO2 emissions are to blame. The perspective authors argue that only by significantly changing the amounts of these other pollutants and carefully measuring the impact on global climate over a period of several decades will science be able to figure out what is going on. “Following this strategy, we will then be able to disentangle the warming and cooling contributions from carbon dioxide and short-lived pollutants, hence placing much tighter constraints on climate sensitivity, and therefore on future climate projections,” they state. See chart below, enlarged here.

And they said it was all carbon dioxide’s fault.

Most of the factors under discussion have relatively short lifetimes in the atmosphere, several less than two months. We do know how the relative influences of these various substances (referred to by climate scientists as “species”) may change in a warming climate. It is also not clear how to reduce short-lived species under present conditions but the uncertainties in atmospheric chemistry and physics must be resolved if Earth’s environmental system is to be understood. Again quoting from the paper:

Of the short-lived species, methane, tropospheric ozone and black carbon are key contributors to global warming, augmenting the radiative forcing of carbon dioxide by 65%. Others – such as sulphate, nitrate and organic aerosols – cause a negative radiative forcing, offsetting a fraction of the warming owing to carbon dioxide. Yet other short-lived species, such as nitrogen oxides, carbon monoxide and volatile organic compounds, can modify the abundance of both the climate-warming and climate-cooling compounds, and thereby affect climate change.

Quantifying the combined impact of short-lived species on Earth’s radiative forcing is complex. Short-lived pollutants – particularly those with an atmospheric lifetime of less than two months – tend to be poorly mixed, and concentrate close to their sources. This uneven distribution, combined with physical and chemical heterogeneities in the atmosphere, means that the impact of short-lived species on radiative forcing can vary by more than a factor of ten with location or time of emission. The situation is further complicated by nonlinear chemical reactions between short-lived species in polluted areas, as well as by the interactions of clouds with aerosols and ozone. These processes add further uncertainty to the estimates of radiative forcing.

Unfortunately, climate models neither accurately deal with local effects of these pollutants nor are the complex interactions among these substances understood. That not withstanding, the report is clear – CO2 does not account for even a majority of the warming seen over the past century. If other species accounted for 65% of historical warming that leaves only 35% for carbon dioxide. This, strangely enough, is in line with calculations based strictly on known atmospheric physics, calculations not biased by the IPCC’s hypothetical and bastardized “feedbacks.”

Of course, the real reason for the feedbacks was to allow almost all global warming to be attributed to CO2. This, in turn, would open the door for radical social and economic policies, allowing them to be enacted in the name of saving the world from global warming. The plain truth is that even climate scientists know that the IPCC case was a political witch’s brew concocted by UN bureaucrats, NGOs, grant money hungry scientists and fringe activists.

Now, after three decades of sturm und drang over climate policy, the truth has emerged – scientists have no idea of how Earth’s climate will change in the future because they don’t know why it changed in the past. Furthermore, it will take decades of additional study to gain a useful understand climate change. To do this, climate scientists will need further funding. Too bad the climate science community squandered any public trust it may have had by trying to frighten people with a lie.

Be safe, enjoy the interglacial and stay skeptical. Read full post here.

Icecap Note: Whatsmore, this totally ignores the other external and internal global factors like solar, ocean multidecadal cycles related to variations in the thermohaline circulation or ocean gyres.

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Here is the paper at Nature Geosciences:

Short-lived uncertainty?

Joyce E. Penner¹, Michael J. Prather², Ivar S. A. Isaksen^3,4, Jan S. Fuglestvedt⁴, Zbigniew Klimont⁵ & David S. Stevenson⁶

1. University of Michigan, Ann Arbor, Michigan 48109-2143, USA
2. University of California, Irvine, California 92697, USA
3. University of Oslo, PO Box 1022, Blindern, 0315 Oslo, Norway
4. Center for International Climate and Environmental Research (CICERO) Oslo, PO Box 1129 Blindern, 0318 Oslo, Norway
5. International Institute for Applied Systems Analysis (IIASA), Schlossplatz 1, 2361 Laxenburg, Austria
6. School of Geosciences, The University of Edinburgh, Edinburgh EH9 3JN, UK.

Correspondence to: Joyce E. Penner¹ e-mail: penner@umich.edu

---

Abstract

Short-lived greenhouse gases and black-carbon aerosols have contributed to past climate warming. Curbing their emissions and quantifying the forcing by all short-lived components could both mitigate climate change in the short term and help to refine projections of global warming.

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Earth’s climate can only be stabilized by bringing carbon dioxide emissions under control in the twenty-first century. But rolling back anthropogenic emissions of several short-lived atmospheric pollutants that lead to warming — such as methane, tropospheric ozone precursors and black-carbon aerosols — could significantly reduce the rate of climate warming over the next few decades^{1, 2, 3}.

 

[TigersEye]

...the truth has emerged – scientists have no idea of how Earth’s climate will change in the future because they don’t know why it changed in the past.

At least that statement rings true.

No Smoking Hot Spot (The Australian)

That article takes Greenhouse Theory at face value and by the criterion set up in the theory itself finds no evidence of warming on the basis of greenhouse effect.

The Hidden Flaw in Greenhouse Theory

Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics

Harvard astrophysicist dismisses AGW theory, challenges peers to 'take back climate science'

It Is Impossible For A 100 ppm Increase In Atmospheric CO2 Concentration To Cause Global Warming

Those four articles each show that Greenhouse Theory has no basis in reality due to a direct conflict with the known laws of physics. No wonder the smoking gun "hotspot" can't be found.

Claim That Sea Level Is Rising Is a Total Fraud

That article pretty much puts the kibosh on any serious trend of planetary warming from any cause. Think about it. If there is absolutely no sign at all of rising sea levels how could the planet be warming? Beyond the centuries long slow warming of the earth and rising of the seas of course. But that is only a few millimeters per century due to the inter-glacial period we are in.

[Wonder Warthog]

Actually, the most important "short lived constituent" is not mentioned int the posting..........droplets of water........i.e. CLOUDS.

In "The Great Global Warming Blunder", Dr. Roy Spencer lays out the case that the global warming models have totally gotten it wrong about the effects of clouds, and proceeds to show precisely how. His peer-reviewed publication covering the subject came out in 2008, and has been largely ignored, both by the media, and by the "climate science" community.

His book shows convincingly that the AGW "scientists" have confused "cause" and "effect" in determining climate sensitivity, and that the actual sensitivity is quite low compared to what is normally assumed.

[Alas Babylon!]

My only question to that is since when has the Planet’s climate EVER been stable?

What is worldwide climate stability, and how can humans do ANYTHING to create it?

[DarthVader]

So have I and this is the first article that I have read that begins to go in that direction. It would be nice to see some scientists get some funding to prove it so it ends this hoax once and for all.

[DarthVader]

“Global warming is the greatest and most successful pseudoscientific fraud I have seen in my life”

My colleague is not kidding!

[Marine_Uncle]

Yet another well written article that brings out the massive AGW scam for what it is.

[Marine_Uncle]

I’ll give the article a closer read tommorow. I’m so beat I can hardly hold my eyes open. Sack time. Do have a great upcoming day.