The Greenhouse Effect and Climate Change - Some Researchers Still Question The Theory Of Climate Change

In the Swiss Review of World Affairs (July 1994), Dr. Richard Lindzen, professor of meteorology at the Massachusetts Institute of Technology, observed that a solid scientific foundation is lacking from claims that global warming is imminent. He believes that Earth's climate depends on more than the CO₂ content. Instead, Earth cools by atmospheric movements upward and poleward rather than only by radiation; and climate changes since 1850 are indistinguishable from natural variability. He further claims that no large-scale model includes all the known major factors in the water vapor cycle. In 1997 Dr. Lindzen added that the natural system has built-in resilience and that the observed changes are insignificant and not urgent.

In October 2003 Anders Sivertsson, Kjell Aleklett, and Colin Campbell, researchers from the University of Uppsala in Sweden, disputed the IPCC's predictions of extreme temperature change due to CO₂ emissions. According to Andy Coghlan in his article "'Too Little' Oil for Global Warming," in the journal New Scientist, the researchers noted that their data show that the world's oil and gas supplies will be depleted long before atmospheric CO₂ concentrations build to sufficient levels to make a major difference in Earth's climate.

Among the claims of critics of global climate warming are:

• The increase in the Earth's surface temperature during the past 150 years is less than the best existing climate models can explain. As the models improve, however, they predict less and less warming.
• Climate has been known to change dramatically within a relatively short period without any human influence.
• Temperature readings already showed increased temperatures before CO₂ levels rose significantly (before 1940).
• Natural variations in climate may exceed any human-caused climate change.
• Some of the increase in temperatures can be attributed to sunspot activity.
• If warming should occur, it will not stress Earth; it may even have benefits, such as for agriculture, and may delay the next ice age.
• Reducing emissions will raise energy prices, reduce gross domestic product, and produce job losses.
• While clouds are crucial to climate predictions, so little is known about them that computer models cannot produce accurate predictions.

FIGURE 2.11
Methane emissions by source, 1990–2002

In 2000 a handful of scientists at the Oregon Institute of Science and Medicine began a drive to collect the signatures of other scientists on a petition reading in part: "There is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gasses is causing or will, in the foreseeable future, cause catastrophic heating of the Earth's atmosphere and disruption of the Earth's climate. Moreover, there is substantial scientific evidence that increases in atmospheric carbon dioxide produce many beneficial effects on the natural plant and animal environments of the Earth." As of April 2004 the so-called Petition Project claims to have collected more than 19,500 signatures, including 17,100 from scientists, mostly with advanced degrees.