Dr. James Hansen, chief global warming alarmist and head of NASA’s Goddard Institute for Space Studies has a new paper in Environmental Research Letters wherein he says that burning coal has caused the hiatus in global temperature rise for the past 15 to 20 years (see here also).
Hansen attributes this to the fact that more carbon dioxide in the atmosphere stimulates plant growth, which, in turn, takes more carbon dioxide out of the atmosphere. “We suggest that the surge of fossil fuel use, mainly coal, since 2000 is a basic cause of the large increase of carbon uptake by the combined terrestrial and ocean carbon sinks. One mechanism by which fossil fuel emissions increase carbon uptake is by fertilizing the biosphere via provision of nutrients essential for tissue building, especially nitrogen, which plays a critical role in controlling net primary productivity and is limited in many ecosystems.” In Hansen’s figure 3, he notes that even though carbon dioxide emissions have been increasing, the airborne fraction of CO2 [the ratio of observed atmospheric CO2 increase to fossil fuel CO2 emissions] has decreased over the past 50 years, especially after the year 2000.
That means that natural processes are compensating for increased emissions. This mechanism is noted in a report by the Center for the Study of Carbon Dioxide and Global Change in which they state: “The productivity of the planet’s terrestrial biosphere, on the whole, has been increasing with time, revealing a great greening of the Earth that extends throughout the entire globe. Satellite-based analyses of net terrestrial primary productivity reveal an increase of around 6-13% since the 1980s.”
Some scientists claim that part of the lack of temperature rise is due to the cooling aerosol effect of sulfur dioxide, also a byproduct of burning coal. Hansen rejects this and is supported by an earlier NASA paper which says that sulfur dioxide (SO2) aerosols in the atmosphere are due mainly to increasing volcanic activity, not from burning coal.
Hansen also notes that the effect [forcing] of man-made greenhouse gas emissions has fallen below IPCC projections, despite an increase in man-made CO2 emissions exceeding IPCC projections.
This paper is quite an admission from someone who once said, “The trains carrying coal to power plants are death trains. Coal-fired power plants are factories of death.”
Hansen’s reasoning seems somewhat circular to me. He’s saying that more carbon dioxide is creating less carbon dioxide. He is also ignoring the fact that as the globe warms (such as warming from the Little Ice Age of the 1850s), the oceans exsolve more carbon dioxide into the atmosphere. He is assuming that carbon dioxide is the major driver of global temperature, a contention for which there is no physical evidence. More likely, the “hiatus in global temperature rise for the past 15 to 20 years” has been caused by something other than carbon dioxide, such as solar cycles which overwhelm the weak warming force of carbon dioxide acting as a greenhouse gas. It is true, however, that as atmospheric carbon dioxide increased, there has been a great greening of the earth as plants respond to the aerial fertilization.
In spite of all the scary scenarios put forth by IPCC climate models, we see that modeling results are an artifact of modeling inputs; that’s a polite way of saying “garbage in – garbage out.” And perhaps Hansen is now realizing the implications of something he wrote back in 1998: “”The forcings that drive long-term climate change are not known with an accuracy sufficient to define future climate change.”
UPDATE: The New York Times reports that James Hansen will quit his NASA job this week to become a full-time climate activist.