The science of climate change has been on the defensive in recent weeks, owing to an error that dramatically overstated the rate at which the Himalayan glaciers could disappear. Some in the media, and those who are sceptical about climate change, are currently having a field day, parsing every comma in the Intergovernmental Panel on Climate Change’s (IPCC) 2007 assessment.
Some strident voices are even dismissing climate change as a hoax on a par with the Y2K computer bug. As a result, the public has become increasingly bewildered, as the unremitting questioning of the IPCC and its chair assumes almost witch-hunting proportions.
The time has really come for a reality check. It is quite right to pinpoint errors, make corrections, and check and re-check sources for accuracy. It is also right that the IPCC has acknowledged the need for ever more stringent and transparent quality-control procedures to minimise any such risks in future reports.
But let us also put aside the myth that the science of climate change is holed below the water line and is sinking fast on a sea of falsehoods.
Over the course of 22 years, the IPCC has drawn upon the expertise of thousands of the best scientific minds, nominated by their own governments, in order to make sense of the complexity of unfolding environmental events and their potential impacts on economies and societies. The panel has striven to deliver the “perfect” product in terms of its mandate, scientific rigour, peer review and openness, and has brought forward the knowledge – but also the knowledge gaps – in terms of our understanding of global warming.
Its 2007 report represents the best possible risk assessment available, notwithstanding an error in its statement of Himalayan glacial melt rates.
One notion promulgated in recent weeks is that the IPCC is sensationalist: this is perhaps the most astonishing, if not risible claim of all. Indeed, the panel has more often been criticised for being far too conservative in its projections of, for example, the likely sea-level rise in the 21st century.
Indeed, caution rather than sensation has been the panel’s watchword throughout its existence.
In its first assessment, in 1990, the IPCC commented that observed temperature increases were “broadly consistent with predictions of climate models, but it is also of the same magnitude as natural climate variability”. The second assessment, in 1995, said: “Results indicate that the observed trend in global mean temperature over the past 100 years is unlikely to be entirely natural in origin.”
In 2001, its third assessment reported: “There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.” By 2007, the consensus had reached “very high confidence” – at least a 90 per cent chance of being correct – in scientists’ understanding of how human activities are causing the world to become warmer.
This does not sound like a partial or proselytising body, but one that has striven to assemble, order and make sense of a rapidly evolving scientific puzzle for which new pieces emerge almost daily while others remain to be found. So perhaps the real issue that is being overlooked is this: confronted by the growing realisation that humanity has become a significant driver of changes to our planet, the IPCC, since its inception, has been in a race against time.
The overwhelming evidence now indicates that greenhouse gas emissions need to peak within the next decade if we are to have any reasonable chance of keeping the global rise in temperature down to manageable levels. Any delay may generate environmental and economic risks of a magnitude that proves impossible to handle.
The fact is that the world would have to make a transition to a low-carbon, resource-efficient future even if there were no climate change. With the world’s human population set to rise from six billion to nine billion people in the next half-century, we need to improve management of our atmosphere, air, lands, soils and oceans anyway.
Rather than undermine the IPCC’s work, we should renew and re-double our efforts to support its mammoth task in assembling the science and knowledge for its fifth assessment in 2014. What is needed is an urgent international response to the multiple challenges of energy security, air pollution, natural-resource management and climate change.
The IPCC is as fallible as the human beings that comprise it. But it remains without doubt the best and most solid foundation we have for a community of more than 190 nations to make these most critical current and future global choices.
The writer is executive director of the United Nations Environment Programme, which co-hosts the IPCC.