Prof. Goose writes: "James Hansen is a physicist, adjunct professor: Earth and Environmental Sciences, Columbia University and director: NASA's Goddard Institute for Space Science. Outside the scientific community Hansen is probably best known for accusing the Bush administration of trying to silence him after he gave a lecture in December 2005 calling for prompt reductions in emissions of greenhouse gases linked to global warming.
In this paper Hansen and Kharecha consider "realistic" (they use EIA data) reserves for oil and gas and conclude that due to approaching peaks it is feasible to keep atmospheric CO2 from exceeding approximately 450ppm as long as coal and unconventional fossil fuels are used responsibly. This article is a discussion of their findings.