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The US Environmental Protection Agency has announced that carbon dioxide and other greenhouse gases will now be officially classed as a pollutant; this is a key break with the policy of the Bush administration and paves the way for the US government to act on climate change.
Dr Colin Summerhayes, Executive Director, Scientific Committee on Antarctic Research (SCAR) at the Scott Polar Research Institute, Cambridge, said:
“CFCs are a pollutant. They caused the ozone hole and they were banned by an international legal instrument -the Montreal protocol. As a result the ozone hole has stabilised, and there are signs that it will begin to diminish and shrink back to its 1980 levels by 2060. The ozone hole was a diect threat to human health since in its absence ultraviolet rays penetrated in larger amounts to the Earth’s surface causing skin cancers in the southern hemisphere.
“By contrast, much of the CO2 in the atmosphere and the ocean is completely natural, so we can’t say that CO2 is a pollutant in the narrow sense of the word. After all, CO2 is what plants use to grow. CO2 only becomes a pollutant when we burn fossil fuels that add CO2 to the atmosphere. It is that “excess” CO2 that is operating as a pollutant. The effect of CFCs was to demolish the ozone hole. The effect of excess CO2 in the air is to significantly warm the atmosphere. Just has CFCs led indirectly (via the ozone hole) to UV radiation, excess CO2 in the atmosphere is leading indirectly (via warming) to melting glaciers and rising sea levels. Rising sea levels will be a hazard to human health over the long term because they will drown coastal communities, flooding coastal city subways and sewers and leading to outbreaks of typhoid and cholera. Similarly warming will affect people on land by causing arid areas and deserts to expand, displacing peoples from around their edge; warming in temperate climates will evaporate more ocean water leading to much heavier rains, causing rivers to flood. And the disappearance of glaciers that store water for the peoples of the plains below the Himalayas will deprive them of year-round water, creating a further health hazard. Finally, the rising content of excess CO2 in the ocean is making the ocean more acid, with the risk of dissolving planktonic organisms with carbonate shells that are the base of the food chain, with knock-on effects likely on fish, seals, seabirds and whales.
“Given these messages it makes sense to cut back on CO2, and we can start by becoming vastly more fuel efficient. Americans are putting 20 tons of carbon into the air per head every year, vastly more than anyone else is emitting. And the result is warming that is growing as the emissions grow, year-on-year. It should be easy to regulate to force automakers to produce much more fuel efficient cars and trucks. This should be good for the economy. It will make the USA less reliant on foreign oil (a good thing). And it will help us to cut emissions significantly.”
Dr Chris Huntingford, Climate Change Modeller at the Centre for Ecology and Hydrology, said:
“The US EPA announcement regarding regulation of greenhouse gases is very timely. State-of-the-art climate model simulations indicate two key things. First, that the current observed warming can almost certainly be attributed to the burning of fossil fuels, and it is not part of a natural cycle. Second, to avoid potentially dangerous alterations to our climate system, greenhouse gas emissions (and in particular carbon dioxide) need to reduce both signficiantly and very soon.
“This is a very timely move by the US EPA which could potentially play a key role in stabilising global climate at safe levels, a task requiring rapid, and major, reductions in CO2 emissions.
“The recognition by the US EPA that greenhouse gases in the atmosphere endanger the welfare of future generations builds on the vast body of scientific evidence now available linking increases in carbon dioxide to global warming. The science shows that such changes almost certainly cannot be attributed to natural cycles in the Earth System.”
Bob Ward, Policy and Communications Director at the Grantham Research Institute on Climate Change and the Environment at London School of Economics and Political Science, said:
“This a very welcome and overdue reversal of one of the most wrong-headed decisions on climate change by the Bush administration, blatantly ignoring the overwhelming scientific evidence that greenhouse gases are harmful pollutants. The EPA’s formal recognition of these greenhouse gases as pollutants means that it can now regulate emissions under the terms of the Clean Air Act. However, its greater significance may be that it will put much more pressure on the United States Congress not to stall on this issue and instead to pass domestic legislation promptly to reduce greenhouse gas emissions. If such legislation is passed before the United Nations climate change conference in Copenhagen in December, President Obama and his negotiating team should be able to play a leading role in securing a strong and binding treaty to reduce global greenhouse gas emissions significantly over the coming decades.
“But without such legislation, the United States will be in a much weaker position and the chances of securing an agreement among all countries will be much lower.”