Shortsighted folly of ignoring the IPCC will lead to drastic future policies.

Nero, the Roman emperor renowned for debauchery and extravagance, is said to have fiddled while Rome burnt. Fast forward a couple of millennia, and little seems to have changed. Today it is the planet, not just one city, that is feeling the heat. And it is world leaders, notably US president Donald Trump, who appeared unmoved. This week, the International Panel on Climate Change reported that a 1C rise in global temperature since pre-industrial times (defined as 1850-1900) was already being felt in the form of floods, droughts, forest fires, and heatwaves.

The original plan to limit the rise to “well below” 2C by 2100 is no longer a viable insurance policy; we should instead aim for no more than 1.5C by 2030. The 12-year survival plan would mean “unprecedented changes” to the way we live, according to the IPCC. It would affect land, energy, industry, buildings, transport and cities. “The next few years are probably the most important in our history,” said the panel’s Debra Roberts. This landmark statement recommending a 1.5 C threshold — particularly as we seem to be heading for a 3C rise by 2100 — should have prompted days of analysis and political hand-wringing.

Instead, the international silence was deafening. Perhaps this reflects the growing parochialism in politics. At a time when national sovereignty is being invoked with angry pride, there is little political bandwidth for a massive problem that is global in nature. Global warming, which transcends borders, is an inconvenient truth for those looking to reimpose them. Climate change denial, no longer a credible political position, has given way to climate change indifference.

There is something for both pessimists and optimists in the IPCC summary for policymakers, approved by signatories to the Paris agreement and issued ahead of an international conference in Poland in December. For the pessimists: a 2C rise would destroy 99 per cent of coral reefs; damage crops; spread diseases such as malaria; damage or kill off certain habitats and ecosystems; and cause migration and poverty. With effort, the optimists can glimpse hope through the haze. Humanity can, with heroic efforts, cap the rise at 1.5C, with attendant benefits: global sea levels still rise but not as dramatically (10cm less than at 2C); we lose most, but crucially not all, of the coral reefs; adaptation and mitigation remain viable; 420m fewer people face heatwaves.

Meeting this stricter target will be monumentally difficult — though not impossible. By 2030, our global CO2 emissions need to fall to 45 per cent of 2010 levels. By 2050, any lingering emissions would need to be sucked out of the atmosphere, by such measures as reforestation and carbon capture and storage. It is, as some have described it, our collective moon shot moment. Rather than accelerating our efforts, however, we are slowing down. According to the International Energy Agency, carbon emissions, which plateaued in 2015 and 2016, are likely to increase this year. We consume too much energy — and still rely on fossil fuels. Such short-sighted folly may force us into more desperate policies in future, such as planet-wide climate engineering.

One technique, which a newly assertive China is studying, injects particles into the stratosphere to scatter sunlight. As well as the peril of unforeseen side-effects, such as changing global rainfall patterns, these largely untested measures raise governance and security issues. Nations could decide unilaterally to act in their own interests, even if it shifts floodwaters elsewhere. If you dislike an America First policy on the ground, how about China First in the stratosphere? Only by refreshing global co-operation can we take the sensible course of action: a Planet First approach.