It is increasingly recognized that, as a result of ever-growing atmospheric inputs of greenhouse gases like carbon dioxide from the burning of fossil fuels, the climate is changing regionally and globally. This has been affirmed, in light of increasing scientific understanding, in the latest report of the Intergovernmental Panel on Climate Change (IPCC) in 2001, by the US National Academy of Sciences in its 2001 report, and most recently by a statement from the Science Academies of all G8 countries, along with China, India, and Brazil. This latter statement calls on the G8 nations to ‘Identify cost-effective steps that can be taken now to contribute to substantial and longterm reduction in net global greenhouse gas emission [and to] recognize that delayed action will increase the risk of adverse environmental effects and will likely incur a greater cost’. Global warming caused by elevated greenhouse gas levels is expressed with long time lags, which can be difficult to appreciate by those unfamiliar with physical systems. Once in the atmosphere, the characteristic residence time of a carbon dioxide molecule is a century. And the time taken for the ocean’s expansion to come to equilibrium with a given level of greenhouse warming is several centuries. If current trends continue, by around 2050 atmospheric carbon dioxide levels will have reached more than 500 parts per million, which is nearly double pre-industrial levels. The last time our planet experienced levels this high was some 20–40 million years ago, when sea levels were around 100m higher than today. It can also be difficult to relate intuitively to the seriousness of the roughly 0.7 °C average warming of the Earth’s surface over the past century. And the warning by the IPCC in its 2001 report, that global warming would be in the range of 1.4–5.8 °C by the end of this century, may also seem unalarming when we experience such temperature swings from one day to the next. There is, however, a huge difference between daily fluctuations, and global averages sustained year on year; the difference in average global temperature between today and the last ice age is only around 5 °C.
CO2 Metallothermal Reduction to Graphene: The Influence of Zn
