Yet again Geoffrey has posted directly from another denier blog without checking the claims. Clearly he trusts that others have done the background work for him. What is ironic is that people of his ilk are highly sceptical of credible peer reviewed science when it disagrees with their ludicrous position but blindly acceptany garbage that supports it. I don’t get it. Maybe I need a degree in psychiatry or psychology to understand the mentality.
Anyway, the latest effort (or lack thereof) is the following post about a 2000 paper by James Hansen et al that deniers are claiming says that CO2 is not the major greenhouse gas responsible for warming. Yet again, this is the problem with reading only the abstract. here is the post.
NASA:GISS: Recent Warming driven mainly by non-CO2 greenhouse gases.Anthony Watts at WUWT and his correspondent Nick have uncovered a paper published by Dr. James Hansen (and the GISS team) in PNAS (Proceedings of the National Academy of Sciences).
Global warming in the twenty-first century: An alternative scenario
- James Hansen*†,
- Makiko Sato*‡,
- Reto Ruedy*,
- Andrew Lacis*, and
- Valdar Oinas*§
No, this isn’t a joke, it isn’t a fake document, and it isn’t a misinterpretation. 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-CO2GHGs 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.
First things first, the notion that this paper has been “long since buried”. There is nothing else to say to this except BULLSHIT. What a load of crap. This paper has been freely available since it was first published. Just because deniers, being the lazy sods they are, couldn’t find it, doesn’t mean it was hidden. I suppose though by pushing that bit of dishonest nonsense they can help to build their assertion that Hansen has egg on his face. I should mention that they have a picture of James Hansenn which has been crudely doctored with a fried egg on his face. A bit juvenile but there you have it.
Now, what of the paper itself? What does it actually say? Here is the full abstract, not the cherrypicked version above. “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 CH4and 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 CO2emissions, 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 importnt thing to note here is not what it says but what it doesn’t say. It doesn’t say here that CO2 is still the largest single forcing but it does acknowledge that aerosols help to cancel out the effect of CO2. Nor does it say that w should stop focusing on CO2 which is the impression Geoffrey and his ilk would like to portray. so here is where reading the paper in its entirety is important. As I said it is freely available. Here are a few key excerts. Highlighting is mine.
“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”
“Our estimates of global climate forcings indicate that it is the non-CO2GHGs 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. “
This graph is the estimated forcings from 1850 to 2000. Figure 1 in the paper. Unless you are completely blind and stupid, it is clear that CO2 is the largest single forcing agent.
“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.”
“The increase in atmospheric CO2 in recent decades (Fig. 2) represents about half of the emissions from fossil fuels and changes in tropical land use; the remaining CO2 from these sources is taken up by the ocean, terrestrial biosphere, and soils. “
So, you be the judge. Was Geoffrey, the blogmaster for the Climate Sceptics Party being completely honest when posting yet another piece of someone else’s work? What does this say about the political party he is affiliated with?