The Times Editorial: Climate Change In Rehab
Humans are interfering with the atmosphere but we are still not sure quite how
Four months ago, high on a mountain in Hawaii, sensitive instruments recorded carbon dioxide concentrations of more than 400 parts per million for the first time in human history. Against this background the world’s most influential climate scientists have gathered in Stockholm in defensive posture. Despite the rise in carbon levels, this is as it should be.
The Intergovernmental Panel on Climate Change (IPCC) has an image problem. Its task in Stockholm is to finalise a new state-of-the-planet report, but since its last one six years ago its credibility has been severely damaged by what came to be known as “climategate”, in which leading scientists appeared to be manipulating results to hide declines in temperature measurements. Average temperatures have in fact been rising, but much slower than expected. Public opinion is growing more sceptical of climate change, not less, and electorates in Australia and Germany have punished parties that put reversing climate change at the centre of their manifestos.
The IPCC appears unsure how to regain the trust of voters and politicians, but not of the science it is supposed to assess. This week’s report is expected to conclude with more confidence than ever that humans have caused more than half the planet’s warming in the past 60 years. This may seem provocative in the circumstances, but the truth is that the the real question for scientists now is not whether climate change is happening but how fast. For policy-makers, the question is what to do about it.
This newspaper has an abiding faith in science — not a blind faith, but a reasonable confidence in scientific methods based on evidence and peer review. That is why, for all the IPCC’s failings, we see in the studies that contribute to its reports a body of evidence pointing to legitimate conclusions.
The basic physics of global warming and the role that carbon dioxide and other gases can play in it were established experimentally by John Tyndall and others by the mid-19th century. The rapid build-up of atmospheric carbon in the modern era has been meticulously measured at the Mauna Loa Observatory since 1958. The planet has warmed in each decade since 1970, even though the process has slowed markedly since 1998. Most of the world’s glaciers have retreated dramatically in the same period.
So far there are only theories as to why the Earth has warmed so much slower in the past 15 years than some models predicted. The models may have been wrong. The scenarios inferred from them may have been alarmist. This much is clear: the IPCC must tackle head-on what it calls the “hiatus” in global warming, and follow the evidence rather than buckle to political pressure from either side of the debate.