Editorial: The unaffordable cost of climate change delay

If there was ever a case of fiddling while Rome burns, then the sadly dilatory global response to the threat from climate change is surely it. Even as weather patterns become measurably more extreme the world over; even as the polar ice caps melt back ever further each summer, opening up newly navigable shipping lanes; even as average global temperatures continue their inexorable rise; still, attempts to forge an international consensus make only glacially slow progress. Yet as research published in this newspaper today makes clear, the longer we take to act, the more unaffordable remedial action becomes.

The most recent foot-dragging was at the UN talks in Doha, which concluded last month. The hope was that the 18th conference on the Convention on Climate Change, attended by nearly 200 countries, would agree rules for an updated treaty – to be signed by 2015 and come into force in 2020 – to impose legally-binding cuts in greenhouse gas emissions on all countries of the world for the first time. But for all the blustering commendations from politicians accompanying the 11th-hour "Doha Climate Gateway", the outcome was disappointing.

In fairness, there was some progress. The existing Kyoto protocol was extended and discussions about the technicalities of the future treaty's negotiating procedure were determined. But the thorniest issues – how, for example, to share the cost of mitigating climate change between developed and developing countries – are no nearer to resolution.

If there were any remaining doubts as to the need for concerted and swift action, however, the latest draft US National Climate Assessment, published on Friday, puts paid to them. The Washington-commissioned analysis makes clear that America is already feeling the impact of global warm- ing; infrastructure, water supplies, crops and coastal geographies are being noticeably affected, it says, while heatwaves, downpours, floods and droughts are all both more common and more extreme. The 240-strong panel of experts also explicitly state, contrary to Republican lore, that rising temperatures are "due primarily to human activities".

It can only be hoped that the findings will galvanise the world's second-largest carbon emitter into action at last. But although President Obama has brought in a smattering of regulations on greenhouse gases, and his energy strategy ultimately aims to wean the US off foreign oil, explicit references to climate change are still few and far between in Washington, and most Republicans refuse to acknowledge any link between human activity and a changing climate. With America central to any meaningful follow-up UN treaty, the tone of the three-month consultation on the Climate Assessment has far-reaching implications.

Evidence is growing, however, that the UN timetable is insufficiently ambitious. Waiting until 2020 rather than pressing ahead now will add £3 trillion to the price tag for corrective measures such as renewable power sources, according to leading climate scientist Dr Keywan Riahi. Seven more years of delay also steadily erodes the probability that the rise in global temperature can be kept below the 2C level at which the consequences become devastatingly destabilising.

As economic malaise leaves the case for environmental policies harder to make, and international efforts lose their gloss, climate change is slipping off the agenda. We cannot afford for it to do so. As the US report says: "Climate change, once considered an issue for a distant future, has moved firmly into the present." There is, then, no more time to waste.