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No, this isn’t a joke, it isn’t a fake document, and it isn’t a misinterpretation. It is a paper published by Dr. James Hansen (and the GISS team) in PNAS (Proceedings of the National Academy of Sciences). In the paper (published in 2000, but long since buried) they make these two bold statements (emphasis mine):
..we argue that rapid warming in recent decades has been driven mainly by non-CO2 greenhouse gases (GHGs), such as chlorofluorocarbons, CH4, and N2O, not by the products of fossil fuel burning, CO2 and aerosols..
If sources of CH4 and O3 precursors were reduced in the future, the change in climate forcing by non-CO2 GHGs in the next 50 years could be near zero. Combined with a reduction of black carbon emissions and plausible success in slowing CO2 emissions, this reduction of non-CO2 GHGs could lead to a decline in the rate of global warming, reducing the danger of dramatic climate change.
Basically what Hansen is saying is that we should focus on air pollution, and some CO2 reduction, but not exclusively on CO2 alone. This is of course at odds with his famous 350ppm CO2 “safe level” upon which the activist organization 350.org is formed, along with many other pronouncements made by Hansen. I post the abstract and excerpts from the PNAS paper below. Be sure to note the item in red. – Anthony
Global warming in the twenty-first century: An alternative scenario
James Hansen*†, Makiko Sato*‡, Reto Ruedy*, Andrew Lacis*, and Valdar Oinas*§
+ Author Affiliations *National Aeronautics and Space Administration Goddard Institute for Space Studies, ‡Center for Climate Systems Research, Columbia University Earth Institute, and §Center for Environmental Prediction, Rutgers University, 2880 Broadway, New York, NY 10025 Contributed by James Hansen
Abstract
A common view is that the current global warming rate will continue or accelerate. But we argue that rapid warming in recent decades has been driven mainly by non-CO2 greenhouse gases (GHGs), such as chlorofluorocarbons, CH4, and N2O, not by the products of fossil fuel burning, CO2 and aerosols, the positive and negative climate forcings of which are partially offsetting. The growth rate of non-CO2 GHGs has declined in the past decade. If sources of CH4 and O3 precursors were reduced in the future, the change in climate forcing by non-CO2 GHGs in the next 50 years could be near zero. Combined with a reduction of black carbon emissions and plausible success in slowing CO2 emissions, this reduction of non-CO2 GHGs could lead to a decline in the rate of global warming, reducing the danger of dramatic climate change. Such a focus on air pollution has practical benefits that unite the interests of developed and developing countries. However, assessment of ongoing and future climate change requires composition-specific long-term global monitoring of aerosol properties.
The global surface temperature has increased by about 0.5°C since 1975 (1, 2), a burst of warming that has taken the global temperature to its highest level in the past millennium (3). There is a growing consensus (4) that the warming is at least in part a consequence of increasing anthropogenic greenhouse gases (GHGs).
GHGs cause a global climate forcing, i.e., an imposed perturbation of the Earth’s energy balance with space (5). There are many competing natural and anthropogenic climate forcings, but increasing GHGs are estimated to be the largest forcing and to result in a net positive forcing, especially during the past few decades (4, 6). Evidence supporting this interpretation is provided by observed heat storage in the ocean (7), which is positive and of the magnitude of the energy imbalance estimated from climate forcings for recent decades (8).
The Intergovernmental Panel on Climate Change (IPCC) (4) has considered a range of scenarios for future GHGs, which is further expanded in its Special Report on Emissions Scenarios (9). Yet global warming simulations have focused on “business as usual” scenarios with rapidly increasing GHGs. These scenarios yield a steep, relentless increase in global temperature throughout the twenty-first century (4, 10) with warming of several degrees Celsius by 2100, if climate sensitivity is 2–4°C for doubled CO2, as climate models suggest (4, 11–13). These figures can give the impression that curtailment of global warming is almost hopeless. The 1997 Kyoto Protocol, which calls for industrialized nations to reduce their CO2 emissions to 95% of 1990 levels by 2012 (14), is itself considered a difficult target to achieve. Yet the climate simulations lead to the conclusion that the Kyoto reductions will have little effect in the twenty-first century (15), and “30 Kyotos” may be needed to reduce warming to an acceptable level (16).
We suggest equal emphasis on an alternative, more optimistic, scenario. This scenario focuses on reducing non-CO2 GHGs and black carbon during the next 50 years. Our estimates of global climate forcings indicate that it is the non-CO2 GHGs that have caused most observed global warming. This interpretation does not alter the desirability of limiting CO2 emissions, because the future balance of forcings is likely to shift toward dominance of CO2 over aerosols. However, we suggest that it is more practical to slow global warming than is sometimes assumed.
…
Climate forcing by CO2 is the largest forcing, but it does not dwarf the others (Fig. 1). Forcing by CH4 (0.7 W/m2) is half as large as that of CO2, and the total forcing by non-CO2 GHGs (1.4 W/m2) equals that of CO2. Moreover, in comparing forcings due to different activities, we must note that the fossil fuels producing most of the CO2 are also the main source of aerosols, especially sulfates, black carbon, and organic aerosols (4, 23). Fossil fuels contribute only a minor part of the non-CO2 GHG growth via emissions that are not essential to energy production.
Aerosols cause a climate forcing directly by reflecting sunlight and indirectly by modifying cloud properties. The indirect effect includes increased cloud brightness, as aerosols lead to a larger number and smaller size of cloud droplets (24), and increased cloud cover, as smaller droplets inhibit rainfall and increase cloud lifetime (25). Absorbing aerosols cause a semidirect forcing by heating the atmosphere, thus reducing large-scale cloud cover (5). In addition, absorbing aerosols within cloud drops and in interstitial air decrease cloud brightness.
Forcing by atmospheric aerosols is uncertain, but research of the past decade indicates that it is substantial (4, 26–28). The aerosol forcing that we estimate (6) has the same magnitude (1.4 W/m2) but a sign that is opposite that of the CO2 forcing. Fossil fuel use is the main source of both CO2 and aerosols, with land conversion and biomass burning also contributing to both forcings. Although fossil fuels contribute to growth of some of the other GHGs, it follows that the net global climate forcing due to processes that produced CO2 in the past century probably is much less than 1.4 W/m2. This partial offsetting of aerosol and greenhouse forcings has been discussed (29–31). Offsetting of global mean forcings does not imply that climate effects are negligible.
A corollary following from Fig. 1 is that climate forcing by non-CO2 GHGs (1.4 W/m2) is nearly equal to the net value of all known forcings for the period 1850–2000 (1.6 W/m2). Thus, assuming only that our estimates are approximately correct, we assert that the processes producing the non-CO2 GHGs have been the primary drive for climate change in the past century.
…
An Alternative Scenario
Let us propose a climate forcing scenario for the next 50 years that adds little forcing (Fig. 5), less than or about 1 W/m2, and then ask whether the elements of the scenario are plausible. The next 50 years is the most difficult time to affect CO2 emissions, because of the inertia of global energy systems, as evidenced by Fig. 4. The essence of the strategy is to halt and even reverse the growth of non-CO2 GHGs and to reduce black carbon emissions. Such a strategy would mitigate an inevitable, even if slowing, growth of CO2. By midcentury improved energy efficiency and advanced technologies, perhaps including hydrogen-powered fuel cells, should allow policy options with reduced reliance on fossil fuels and, if necessary, CO2 sequestration.
…
Summary
Business-as-usual scenarios provide a useful warning about the potential for human-made climate change. Our analysis of climate forcings suggests, as a strategy to slow global warming, an alternative scenario focused on reducing non-CO2 GHGs and black carbon (soot) aerosols. Investments in technology to improve energy efficiency and develop nonfossil energy sources are also needed to slow the growth of CO2 emissions and expand future policy options.
A key feature of this strategy is its focus on air pollution, especially aerosols and tropospheric ozone, which have human health and ecological impacts. If the World Bank were to support investments in modern technology and air quality control in India and China, for example, the reductions in tropospheric ozone and black carbon would not only improve local health and agricultural productivity but also benefit global climate and air quality.
==============================================================
So the strategy should be to focus on air pollution, not CO2
Think I made all this up? Read the paper at PNAS here.
(Big hat tip to WUWT reader Nick.)
Backup link in case it disappears like so many other things is here.
Now for the other shocker. This paper was published in the year 2000. So what happened to Hansen since then? He’s totally lost the plot from then, which from my perspective, seems reasonable, and one I could get behind.
Instead we have pronouncements like this:
2008 from a non peer reviewed paper published on Hansen’s personal website –
If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from its current 385 ppm to at most 350 ppm.
2009 in a article in the UK Guardian. Hansen says –
“The trains carrying coal to power plants are death trains. Coal-fired power plants are factories of death.”
And this:
Clearly, if we burn all fossil fuels, we will destroy the planet we know. Carbon dioxide would increase to 500 ppm or more.
May 10th, 2012 Game over on Climate, New York Times op-ed –
Canada’s tar sands, deposits of sand saturated with bitumen, contain twice the amount of carbon dioxide emitted by global oil use in our entire history. If we were to fully exploit this new oil source, and continue to burn our conventional oil, gas and coal supplies, concentrations of carbon dioxide in the atmosphere eventually would reach levels higher than in the Pliocene era, more than 2.5 million years ago, when sea level was at least 50 feet higher than it is now. That level of heat-trapping gases would assure that the disintegration of the ice sheets would accelerate out of control. Sea levels would rise and destroy coastal cities. Global temperatures would become intolerable. Twenty to 50 percent of the planet’s species would be driven to extinction. Civilization would be at risk.
No mention of the other GHG’s, carbon soot, and aersols in that op-ed.
Clearly he seems to have abandoned the idea that seemed so reasonable and workable in his 2000 paper for the idea that CO2 reduction and removal of fossil fuels from the energy equation is the only possible scenario.
I think he was affected by the money, power, and hoopla surrounding Al Gore’s success with the alarming fabrications in An Inconvenient Truth as well as the hoopla and fame associated with the Nobel prize for the 2007 IPCC report. (Added: it is important to note that all of this backpedaling occurred after Hansen’s 1988 Senate testimony where he and sponsoring Senator Tim Wirth were so sure of the science blaming CO2 saying “that it was 99 percent certain that the warming trend was not a natural variation but was caused by a buildup of carbon dioxide and other artificial gases in the atmosphere.” that they had a thermostat malfunction in the hearing room, it came after Rio Earth Summit 1992, and the subsequent Kyoto protocol. Now Hansen has flip-flopped again with more recent CO2 pronouncements.)
When you go from scientist to arrested activist, the reasonable path just doesn’t get people stirred up. It seems Dr. Hansen has gone over to the dark side of the forcings.
Ask Dr. Hansen’s acolyte Bill McKibben how well reasonable approaches work in all the wailing hippie protests he organizes. You can connect the dots.
UPDATE: graph added, thanks to Joshua Halpern of Howard University who says:
Eli Rabett on 2012/06/03 at 10:42 am says:
That was 2000, this is 2012. As that paper said, the alternative strategy would buy time, not solve the problem. We didn’t follow it and are now running out of time. Twelve years is a while.
REPLY: Yes as noted clearly in red, that was 2000. Twelve years without warming is a while.
http://www.woodfortrees.org/plot/hadcrut3vgl/from:2000/plot/hadcrut3vgl/from:2000/trend
What’s the rush? Meanwhile:
NOAA: Carbon dioxide levels reach milestone at Arctic sites
NOAA cooperative measurements in remote, northern sites hit greenhouse gas milestone in April
– Anthony
UPDATE2: It gets stranger. WUWT reader Jimbo points out in comments, that Hansen wrote a paper blaming soot for the Arctic ice melt, calling it twice as effective as CO2.
Soot climate forcing via snow and ice albedos James Hansen* †‡ and Larissa Nazarenko* †
Plausible estimates for the effect of soot on snow and ice albedos (1.5% in the Arctic and 3% in Northern Hemisphere land areas) yield a climate forcing of 0.3 Wm2 in the Northern Hemisphere. The ‘‘efficacy’’ of this forcing is 2, i.e., for a given forcing it is twice as effective as CO2 in altering global surface air temperature.
Global Warming. Soot snowice albedo climate forcing is not included in Intergovernmental Panel on Climate Change evaluations. This forcing is unusually effective, causing twice as much global warming as a CO2 forcing of the same magnitude. This high efficacy is a straight-forward consequence of positive albedo feedbacks and atmospheric stability at high latitudes. Our estimate for the mean soot effect on spectrally integrated albedos in the Arctic (1.5%) and Northern Hemisphere land areas (3%) yields a Northern Hemisphere forcing of 0.3 Wm2 or an effective hemispheric forcing of 0.6 Wm2 . The calculated global warming in an 1880–2000 simulation is about one quarter of observed global warming
Source: pubs.giss.nasa.gov/docs/2004/2004_Hansen_Nazarenko.pdf
With apologies to Shakespeare/ Hamlet –
“There are more things in heaven and earth, Hansen,
than are dreamt of in your philosophy.
To put a crazy disposition on,
That you, at such times seeing me, never shall,
With arms encumber’d thus, or this headshake,
Or by pronouncing of some doubtful phrase,
As ‘Well, well, we know,’ or ‘We could, an if we would,’
Or ‘If we list to speak,’ or ‘There be, an if they might,’
Or such ambiguous giving out..”
“Hansen/GISS team”
Maybe Josh can conjure up a “toon” that expresses just how well traveled around a “gas” chart these people have become. Maybe little pin flags…….”Yeah, yeah, that’s the gas…Who da gas? Dis da gas!”, or “Gas/Cause of da Month is…..(dramatic pause)….”Soot!”.
What a house of mirrors…..you would think it would be embarrassing after a while.
Perhaps (published in 2000, but long since buried) is a little harsh as it appears in the references for WG3 of the TAR (2001) – http://www.ipcc.ch/ipccreports/tar/wg3/index.php?idp=67
Maybe stuck behind a filing cabinet or taped to the bottom of a drawer if it is not in a public listing of papers.
Either way, ‘The science is settled’ rings even less true, even if this is more than a decade old.
Has anybody else noticed that every year contradictory predictions are made based on “Man Made Climate Change”? (They came up with “Climate Change” to account for the lack of warming.) The prediction that gets the press is the one that seems to fit what actually happened.
I wonder if this paper was something along those lines? A “CYA” paper in case CO2 didn’t stick to the wall?
Many of you have followed and actually understand the science behind the details through the years. Does make sense?
The paper was not buried. All that we have here is confirmation that the blogsphere is not the best place to do science. Trying to buy time by looking at non CO2 factors is nothing new or radical.
REPLY: Well, that’s your opinion. Suitable for DK.
“The Intergovernmental Panel on Climate Change (1) estimates
the global climate forcing by fossil fuel black carbon (BC)
aerosols as 0.2Wm2. Jacobson (2) suggests that the fossil fuel BC
forcing is larger,0.5Wm2. J.H. and colleagues (3–5) have argued
that the total anthropogenic BC forcing, including BC from fossil
fuels, biofuels, and outdoor biomass burning, and also including the
indirect effects of BC on snowice albedo, is still larger, 0.8 0.4
Wm2. Here we estimate the magnitude of one component of the
BC climate forcing: its effect on snowice albedo.”
Was this prior to WG3 and what did WG3 have for the BC forcing?
The strain to decive themselves must be expressed now in hockey stick to the groin pain levels.
[snip – policy violation – shape shifter – posting under many different names using proxy servers and fake emails – but how’s UoG ]?
Myrrh says:
June 4, 2012 at 3:52 am
Here, a real picture of carbon dioxide levels worth a thousand words:
http://www.biomind.de/realCO2/literature/evidence-var-corrRSCb.pdf
__________________________________
A second thank you for that link Myrrh. Beck never got the recognition he deserved.
Mike – “All that we have here is confirmation that the blogsphere is not the best place to do science.”
What we have is further evidence that AGW cabal is dishonest in that they loudly proclaim anything that even remotely suggests AGW; while being silent on anything that even remotely goes against AGW.
Need an example? AGW widely publicized picture of the lone polar bear on a small chunk of ice as proof of AGW. But the AGW never bothered to publicize the picture showed no such thing being it was used out of context of which it was taken, nor did the AGW cabal bother to report polar bear population was either stable or possibly slightly on the rise.
Maybe buried was too strong of a word, but there definitely seems be attempts to “disassociate” this paper.
What exactly is it “here” that confirms this?
Claiming that rapid warming over recent decades is mainly due to chlorofluorocarbons, CH4, and N2O while simultaneously claiming that rapid warming over recent decades is NOT the product of fossil fuel burning (CO2) is most certainly a radical claim for a warming alarmist.
Of interest from Myrrh’s posted pdf link:
“These atmospheric CO2 data show a flat contour during a period of about 50 years from about 1875 to 1925, but they also show the CO2 concentration has fluctuated 3 times since 1812 with maxima around 1825, 1857 and especially well documented a maximum in 1942 of up to 410 ppm. These fluctuations are not shown in the ice core reconstruction.”
How convenient for AGWers that Ice Cores flat line. Hide the Fluctuations!
Robbie says:
June 4, 2012 at 7:44 am
You said in your earlier post:
What Hansen and team are saying (well proposing) is the fact that Non-CO2 GHGs have a stronger forcing than CO2 had so far (in 2000).
When you read the paper you must have missed this line from it:
Climate forcing by CO2 is the largest forcing, but it does not dwarf the others (Fig. 1).
You said in your last post:
Btw: Was that site http://www.esrl.noaa.gov/gmd/aggi/ also there in 2000?
I think not. That’s what we gained at knowledge in the last 12 years.
AGGI has been available since 2004 but all the data has been available since 1979 when NOAA’s global air sampling network expanded significantly. Do you seriously expect me to believe that Hansen didn’t have access to the NOAA data? He would be a very incompetent researcher indeed if he did not know that since 1979 at least CO2 has always been the largest component of GHG forcing. Indeed, in his paper he asserts that his Figure 1 applies since 1850. This is stated in the line under the heading ‘Climate Forcings in the Industrial Era’ on page 9875.
Are you reading the same paper as me?
just in case its pdf’d and saved here too
http://www.davemacleod.net/forums/topic/46370-pnas-paper/
Bah, you are telling me that Hansen and I actually sort of agree on something? (Black soot impacts the arctic more than CO2 does… It probably impacts glaciers as well)
I need a stiff drink now… I feel so…dirty…probably from the black soot.
Concerning the side-topic of gypsy moths brought up by LKMiller on June 4, 2012 at 4:07 AM:
When they get out of control, gypsy moth catapillers eat everything. Maybe they prefer oaks, but I recall a forest in Southern Maine around 1980 that looked like a war zone. If a leafless forest wasn’t strange enough, in the middle of summer, the forest also lacked any needles on the white pines. As white pines keep their needles in the winter, this forest looked like nothing I had ever seen before.
I think what they do now, when one of these situations starts to develop, is to hustle in some sort of fungus that spreads through the over-population, and causes all the catapillers to shrivel up.
LKMiller says:
June 4, 2012 at 6:10 am
@ur momisugly me, June 4, 2012 at 4:07 am:
Sorry Bill, gypsy moth larvae feed almost exclusively on oak species, so the Pine Barrens (mostly pitch pine (Pinus rigida) in NJ are unaffected by this introduced insect pest.
As Caleb noted, when the GM reaches infestation stage, they’ll eat anything green, including pitch pine needles and laurel leaves. During one outbreak in the mid-’80s, the area between Chatsworth and Tuckerton looked like it had been a Ranch Hand practice area.
Aerial application of Bacillus thuringiensis (Bt) is an effective caterpillar-cide — one year, the greenies in Princeton spread the rumor that Bt was harmful to toddlers, so the citizenry petitioned the state to forego spraying the township. By the time the residents realized they’d been had, the caterpillars had stripped all the trees in town and were eating the lawns.
****
Bill Tuttle says:
June 5, 2012 at 6:07 am
As Caleb noted, when the GM reaches infestation stage, they’ll eat anything green, including pitch pine needles and laurel leaves. During one outbreak in the mid-’80s, the area between Chatsworth and Tuckerton looked like it had been a Ranch Hand practice area.
Here in west MD, gypsy moths have received a knockout blow. When I first moved here in 2004, I saw a very few hanging on tree-trunks, infected by a fungus. Since then haven’t seen a single one, nor noticed any damage anywhere along my travels. I believe the fungus had been purposely introduced some decades before, but hadn’t taken hold until ~2000 or so.
In the ’70s, ’80s, GMs had defoliated entire mountainsides in w MD.
James Sexton says:
June 3, 2012 at 9:36 am
“Hansen’s views on warming continue to “evolve”….. or flip flop, depending upon your political persuasion.”
If you, and a number of other Hansen admirers participating, were totally convinced by his pre 2000 CO2 bugaboo and its consensus, and then by his switch over to a more benevolent attitude towards CO2 after having demonized and disrupted the energy industry, and then finally return to his CO2 death metaphors since 2000, what can you possibly base your absolute trust in this man’s work on? You have answered this clearly: you are ‘depending on your political persuasion’ – much of the concern by scientifically literate skeptics is precisely because of this political motivation of buying into a new world order. As is always the case, someone has to save people from themselves. Oh and by the way, Switching from belief A to B and back to A is the very definition of “flip flop” whether you are a socialist, dictator or anything in between.
I believe Hansen will find a lot of use for this paper in the coming years. Oh, and has he written any pithy papers on astronomy, his actual discipline, in the last 30 years?
Hansen’s buried paper has over 500 citations. See Google Scholar.
What’s the name on that policeman’s shirt? Is that ironic or what?
Bill Tuttle says:
June 5, 2012 at 6:07 am
Aerial application of Bacillus thuringiensis (Bt) is an effective caterpillar-cide — one year, the greenies in Princeton spread the rumor that Bt was harmful to toddlers, so the citizenry petitioned the state to forego spraying the township. By the time the residents realized they’d been had, the caterpillars had stripped all the trees in town and were eating the lawns.
Nice story Bill, shame it didn’t happen!
I think I’ve worked it out. Developing countries are responsible for the ‘forcing’ due to lack of pollution control. Naturally this means that developed countries should immediately feel guilty and pay to clean up the developing nations mess.
Think that covers it.
Wow, you just discovered a 12 year old paper. I guess I’ll check back in two years when you find the response to the paper (Wuebbles,2002) and the response to the response (Hansen, 2002)