People tend to have one of two broad reactions to bad news on the climate: hopeless despair and unjustified optimism. Neither reaction is right.
We鈥檝e seen this yet again in the response to the Hothouse Earth story this week 鈥搕he suggestion that once Earth warms by a certain amount, maybe just 2掳C, a cascade of tipping points will keep it warming even if our greenhouse gas emissions cease.
This paper would probably have got little attention a few months ago. But after months of record heat in many parts of the northern hemisphere, it got massive coverage and .
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This then led to a pushback from some climate scientists and campaigners worried about the impact of this kind of coverage.
鈥淵es, the prospect of runaway climate change is terrifying. But this dead world is not our destiny. It鈥檚 entirely avoidable,鈥� Eric Holthaus, a former meteorologist who now writes for Grist, an environmental website.
Heated debate
The first thing to say is that the Hothouse Earth paper was an opinion piece in a scientific journal, rather than entirely new research. It鈥檚 a possibility, but far from being the mainstream view of climate scientists. But let鈥檚 assume it鈥檚 right, and that the world will keep on warming once it reaches 2掳C above preindustrial.
If so, it is simply wrong to claim we can still avert major global warming. The world is currently on track to warm 3 or 4掳C even if we don鈥檛 trigger a cascade of tipping points.
Limiting warming to 2掳C would require immediate and drastic policy changes 鈥� such as clamping down on flying and eating meat 鈥� that would have a huge impact on our lifestyles and parts of the economy.
There is no sign of any single country yet being prepared to go that far, let alone enough countries to alter the world鈥檚 course.
This means we are setting in motion huge changes that cannot be stopped. Most notably, there may already be no way to prevent sea level rising at least 5 metres.
But it is also wrong to go to the other extreme and claim we are doomed. For starters, no scientists are claiming a Hothouse Earth will happen anytime soon.
Many of the聽processes that could push the Earth towards this state operate over centuries and millennia. And while , almost all glaciologists think the melting of polar ice sheets will take many centuries. So this is mostly about what happens after 2100, not before.
There is still time to prepare and adapt, then. And what we do still matters even in this worst-case scenario, because the more we do to reduce emissions, the more time we will buy ourselves.
There is still one huge factor in our favour: the warmer the planet gets, the harder it is to warm it further. It will take twice as much carbon dioxide to warm the planet from 1.5 to 3掳C as it will to warm it from pre-industrial levels to 1.5掳C.
We need to make the most of this time, and get serious about adapting our cities and farms for a warmer world. Among other things, that means thinking about where we build and what we build it, from homes to cities to power stations.
The time is now
Politicians and planners have not yet begun to grasp the magnitude of the challenge. For instance, much major infrastructure is still being built in low-lying coastal areas that will be extremely costly to protect from rising seas if it can be done at all.
There鈥檚 no doubt that climate change will be mostly bad. People are already dying after just 1掳C of warming. But how bad it gets in the future depends not just on how much the planet warms but how much we do to adapt to life on a warming planet with rising sea levels and ever more extreme weather.
Bad times are not the same as end times. More warming is inevitable. The end of civilisation is not.
