Monday, July 20, 2009

World starts to act on climate change

From the G8 to shipping, the world's climate players are starting to bring their contributions to the table – is real change imminent?

 The world's climate players are starting to bring their contributions to the table (Image: Corbis)

IT'S like a giant game of Jenga. One by one, pieces of our green future are stacking up, some more precariously than others.

At last week's summit in L'Aquila, Italy, leaders of the G8 declared formally for the first time that the world should not allow global temperatures to rise by more than 2 °C above pre-industrial levels. The group also backed Mexico's plan for a green fund to help the poorest countries develop clean-technology economies.

Meanwhile, in London this week, the shipping industry is meeting to see if it can agree on a way of cutting emissions. Come December, it will be down to UN negotiators to decide which pieces are solid and which are not.

Take the 2 °C target, for instance. The truth is that few climate scientists believe this is possible, even with the G8's proposed target of cutting global emissions of greenhouse gases by 50 per cent by 2050. "An overshoot is inevitable," concluded a recent climate science summit in Copenhagen, Denmark (New Scientist, 21 March, p 6). "Atmospheric CO2 concentrations are already at levels predicted to lead to global warming of between 2.0 °C and 2.4 °C."

Global average temperatures so far have risen by only about 0.8 °C but there are two reasons why warming three times as great seems inevitable. First, there is a time lag of several decades between when greenhouse gas levels rise and when temperatures follow. The lag means there is another 0.6 °C of inevitable warming in the pipeline.

Second, the planet is currently being cooled by about 0.5 °C by aerosols of other man-made air pollutants, such as fine soot and sulphates, which shield the planet from solar energy. This effect should decline in coming decades as countries, particularly in Asia, clean up their air to improve health. Add it all up and we're close to 2 °C above pre-industrial times.

Taking this into account, the World Economic Forum's Global Agenda Council on Climate Change told the WEF meeting in Davos in January that we should aim for a global 80 per cent emissions cut by 2050, which it estimated would give a 4 in 5 chance of staying below 2 °C. …

World starts to act on climate change

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