Follow The Science On Climate Change

Published: November 1 2009 17:30 | Last updated: November 1 2009 17:30

More on the skepticizm about global warming. Please read.


As next month’s Copenhagen conference approaches, politicians should not be distracted by the apparently growing volume of sceptical voices challenging the need for global action against climate change. Some of the sceptics may have scientific backgrounds but they are not in the mainstream of contemporary climate research. The real experts – hundreds of scientists worldwide who are examining the link between climate and carbon dioxide emissions – have no doubt that man-made global warming is a real crisis that must be addressed urgently.

When science and politics mix, scientists have to simplify their arguments to enable politicians to grapple with the issues. The sheer complexity of climate science, from atmospheric physics to polar glaciology, makes it harder to convey than some other science-based issues such as space policy, stem cells or HIV/Aids. And there has inevitably been oversimplification – sometimes amplified by environmental groups keen to present the threat of global warming in the starkest terms.

The most important point to grasp about global warming is that it has not proceeded and will not continue at anything like a uniform, predictable pace around the world. As sceptics like to point out, 1998 was the warmest year on record globally (because of a particularly intense El Niño event in the Pacific Ocean) but locally things have heated up considerably since then – especially in the Arctic, where summer sea ice has shrunk alarmingly over the past five years.

A common mistake is to try to draw a clear distinction between “man-made” and “natural” change. The real climate results from an incredibly complex interplay between natural variation and the increasingly important human influence.

The geological record shows that natural change can happen extremely fast – on several occasions within the past 20,000 years global temperatures have risen or fallen by several degrees over a century. Sceptics sometimes seem to draw comfort from this natural variability but, to a climatologist with a sense of history, the wild swings in the past are anything but comforting. They suggest a real (though probably small) risk that, by pumping carbon dioxide in the atmosphere to levels not seen for millions of years, we could trigger catastrophic, runaway global warming.

Future climate is intrinsically unpredictable. For planning purposes policymakers need projections of changes decades ahead, and scientists oblige by issuing consensus forecasts through bodies such as the Intergovernmental Panel on Climate Change.

Remember that the figures are not firm predictions. If climate is less sensitive to increasing carbon dioxide than the models suggest – or if unexpected natural events, such as a slight dimming of the sun or exceptional volcanic activity, intervene – then we may get away with little warming. The most likely rise in global temperature is somewhere between a just manageable 2°C and potentially catastrophic 4°C, depending on how quickly the world gets a grip on emissions. It could be even worse than that.

Ultimately, when all the uncertainties are combined with the scientists’ view that we are doing something significant to the global climate, a good reason why the world should invest hundreds of billions of dollars in cutting carbon emissions is to insure against truly cataclysmic climate change that might destroy industrial civilisation – a case made persuasively by Martin Weitzman, the Harvard economist.

Fortunately the science becomes much clearer when we move from predicting the climate itself to assessing how best to reduce carbon dioxide in the atmosphere. Forget about esoteric “geo-engineering” proposals to cool the earth. Technology that already exists (or is in development) can do the job perfectly well by increasing the efficiency with which we use carbon-based energy.

The least glamorous forms of energy conservation, such as insulating buildings properly and making transport more efficient, still have a huge contribution to make. So do nuclear power and the various forms of renewable energy from sun to wind and waves, though it will be essential to invest heavily in “smart grid” technology to make the best use of them. As the final pre-Copenhagen negotiations begin in Barcelona, an editorial in Tuesday’s FT will outline the policies that can make a real difference to climate change without causing unacceptable disruption to the global economy.

Copyright The Financial Times Limited 2009.


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