Climate change is happening - but it's not too late

The findings of the United Nations Intergovernmental Panel on Climate Change are frighteningly clear. Our environment is incontestably warming – each of the past three decades has been successively warmer than any since 1850 – and it is beyond reasonable doubt that human activities are the cause.

The fifth IPCC report may not contain much that is absolutely new. What has changed, though, since 2007, is the degree of certainty. It is now as sure that human beings are causing climate change – 95 per cent – as that cigarettes cause cancer. This is not the judgement of politicians or campaigners; it is the consensus of hundreds of scientists, from all over the world, having considered all the available evidence. One can only hope that it will banish the scepticism of the ignorant and the threatened from serious public debate at last.

The effects of the alterations in Earth’s environment are already being felt, and not just in “extreme weather events”. The polar ice sheets are thinning, sea levels are rising and the oceans are increasingly acidic. More concerning still is what is to come. The likelihood that temperature rises will stay below the 2C threshold, above which changes become catastrophic, looks less and less achievable. Indeed, we have already burned through 54 per cent of the “carbon budget” calculated to equate to a 2C spike.

Without radical action, the outlook is bleak. But the politics of long-term, counter-factual disaster-avoidance are no easier than they were. The International Development Secretary made the right noises yesterday, observing that Britain must play its part; yet the Chancellor judges the green agenda an unaffordable luxury in times of public austerity. Equally, Ed Miliband talks a good game with his promise of carbon-free electricity by 2030; but his promise to freeze energy bills raises questions about where the investment will come from and also spooks potential investors.

On the other side of the Atlantic, John Kerry responded to the IPCC in stirring terms. “This is yet another wake-up call: those who deny the science or choose excuses over action are playing with fire,” the Secretary of State said, before going on to affirm that the US is “deeply committed to leading on climate change”. Yet Congress is in the midst of yet another budget fight, and one of the Republican demands, upon which new borrowing is conditional, is a weakening of carbon-emission regulations.

The sceptics are right about one thing: the cost of mitigating climate change is certainly high. But it is also unavoidable; and the bill will only rise – in terms of money and human lives – the longer we delay. We must, then, throw all we have at the problem, from the incremental (insulating our houses) to the fundamental (re-thinking industry and transport). And thorny diplomatic issues over who should pay – the rich countries that did the historical polluting, or emerging economies now industrialising in double-quick time – cannot be ducked.

Ultimately, the solution lies with the market. It is easy to write off carbon trading. Europe’s ground-breaking scheme has floundered, its price meaninglessly low. In the US, Barack Obama’s hopes for national cap-and-trade were dashed by the Senate, leaving only a smattering of regional initiatives. The new Australian Prime Minister wants to repeal his predecessor’s carbon “tax”. Despite the teething problems, though, a global price on carbon is vital and must be priority; and with China and South Korea now putting together their own schemes, there is at least some progress being made.

Climate change is, simply, the biggest single challenge that has faced the human race. If it is not an existential threat for all of us, then it certainly is for some – maybe many. In response, we must fundamentally change the way we do things. It will not be easy, but adaptation is, after all, what we are good at. We also have no choice; after yesterday, that is clearer than ever.