NEW SCIENTIST issue: 2214, volume: 164, year: 1999, pages: 5 - 5 Writing on the wall Understanding global warming is fine, the point is to stop it CONSENSUS is a dangerous thing in science. The notion that researchers can ever prove their theories is long gone--they can only wait for others to knock them down. This means that to be healthy, science needs an opposition, and when politicians ask scientists to reach a common view, it pays to be wary. For a decade now, the UN's Intergovernmental Panel on Climate Change (IPCC) has had the task of moulding adversarial science into a consensual form. Its third assessment of climate change science, now circulating in draft form for comment, is an impressive example of the art, dealing as it does with a controversial matter of utmost importance to the whole world. As we reported last week, the IPCC says there is now little room for doubt that global warming in the past 25 years is our fault. With the help of increasingly successful climate models, it lays out our likely future in awful detail. We have probably already signed death warrants for several low-lying Pacific islands, casualties of rising sea levels. And if we let concentrations of greenhouse gases increase more than 50 per cent above present levels--which could happen by the middle of next century--the Amazon rainforest will simply shrivel up and die. Of course, committees charged with reaching a consensus may gloss over contentious details, and simplified models of the real world still leave plenty of room for improvement. We know little about how clouds created by extra evaporation in a warmer world will influence temperature. And there is an alarming fuzziness about atmospheric mechanisms that could turn small changes in solar radiation into large temperature swings here on Earth. But the IPCC's draft report is honest on these points, stressing that uncertainty should be a cause for more concern, not an excuse for delaying action. Among other uncertainties, it asks whether melting Arctic ice will dilute the waters of the North Atlantic, shutting down a massive "pump" that is driven by salty waters sinking to the ocean floor. If this happens, it would reduce the ocean's uptake of carbon dioxide and accelerate global warming. Perversely, it would also cut off the currents that warm Western Europe, so London, Paris and Madrid would shiver while the rest of the world sweltered. In this issue we report the first evidence from the Atlantic that this hypothetical event may be starting to happen. In the few years since the world woke up to the threat of climate change, science has made impressive strides in describing how Earth's life-support systems work. At a meeting in Bonn earlier this month, where more than 160 governments discussed targets for cutting emissions of greenhouse gases, NOT ONE VOICED DOUBTS ABOUT THE SCIENTIFIC UNDERPINNINGS OF THEIR DELIBERATIONS. But can you have too much of consensus? The IPCC must guard against this. It makes a point of drawing sometimes hostile sceptics into its deliberations. The latest report, for instance, includes major contributions from researchers studying the potential impact of changes in solar radiation on our temperature. It has also set up a group specifically to search for scientific surprises that could upset its calculations. Dangerous it may be, but the IPCC has turned consensus into a virtue. It is now time for governments to show that they can act as one to halt the coming nightmare.
Thursday, November 26, 2015
Writing on the wall - Understanding global warming is fine, the point is to stop it
Posted by S F X at 8:11 PM