“Once we understand the extremity of our plight, once we no longer deny it, then we just might have the will to try drastically to change course”, Rupert Read wrote in The London Economic shortly after the winter cold snap brought a record-breaking chill to British shores. As the continent basks in heat the latest study from an international team of climate researchers shows we are heading for a Hothouse Earth scenario which could turn some of the Earth’s natural forces that currently protect us into our enemies. But as Read noted back in March, the tragedy about the situation that we find ourselves in is that “if collectively we only had the will, it would be perfectly possible for us to make the changes needed in order to save ourselves”.
According to reports published in the journal Proceedings of the National Academy of Sciences if global temperatures cross a 2C threshold we could embark on a path leading to boiling hot temperatures and towering seas in the centuries to come. The Earth’s forests, oceans and land – which currently soak up about 4.5 billion tonnes of carbon that would otherwise end up in our atmosphere – could see their roles reversed becoming sources of carbon and making the problems of climate change significantly worse.
Co-author Prof Johan Rockström, from the Stockholm Resilience Centre, told BBC News: “What we are saying is that when we reach 2 degrees of warming, we may be at a point where we hand over the control mechanism to Planet Earth herself. We are the ones in control right now, but once we go past 2 degrees, we see that the Earth system tips over from being a friend to a foe. We totally hand over our fate to an Earth system that starts rolling out of equilibrium.”
In the study the authors looked at ten natural systems which they term “feedback processes” that help humanity to avoid the worst impacts of carbon and temperature rises. The worry is that if one of these systems tips over and starts pushing large amounts of CO2 into the atmosphere, the rest could follow like a row of dominoes, triggering a Hothouse Earth period. If that occurs, we would see a higher global temperature than at any time in the past 1.2 million years. The seas could be 10-60 metres higher than now, rendering some parts of the Earth completely uninhabitable.
The impacts would be “massive, sometimes abrupt and undoubtedly disruptive,” the authors say.
But it’s not all bad news. We can avoid the hothouse scenario if we accept that it will take a fundamental re-adjustment of our relationship with the planet.
“Climate and other global changes show us that we humans are impacting the Earth system at the global level. This means that we as a global community can also manage our relationship with the system to influence future planetary conditions.
“This study identifies some of the levers that can be used to do so,” says co-author Katherine Richardson from the University of Copenhagen.
By the middle of this century we need to stop burning fossil fuels, plant considerably more trees, protect forests and innovate to find ways of blocking the Sun’s rays and develop machines to suck carbon out of the air. “We must all become stewards of the Earth”, the authors note. Or just take responsibility for the chain of events we have caused. But it seems unlikely that will happen.
“Given the evidence of human history, this would seem a naive hope,” said Prof Chris Rapley, from University College London.
“At a time of the widespread rise of right-wing populism, with its associated rejection of the messages of those perceived as ‘cosmopolitan elites’ and specific denial of climate change as an issue, the likelihood that the combination of factors necessary to allow humanity to navigate the planet to an acceptable ‘intermediate state’ must surely be close to zero.”