Climate: Even briefly overshooting 2°C will cause permanent damage

The history of climate change is one of people slowly coming to terms with the truth. None but a small minority still question whether it’s real and caused by humans. Now most grapple with the reality of trying to slow down catastrophic warming, and the difference between solutions and false hope. The concept of climate overshoot is the next thing we will need to get to grips with.

Unless urgent action is taken, emissions are expected to cause the planet to continue heating rapidly over the next few decades, prompting the global average temperature to overshoot the Paris agreement’s target, which aimed to limit warming to between 1.5°C and 2°C. A period of higher temperatures will occur in the middle of this century as a result. Then, the idea goes, new but yet unproven technologies and techniques for pulling greenhouse gases from the atmosphere will eventually bring temperatures back down to a safer level.

Until now, scientists were unsure what temporarily overshooting (and then boomeranging back below) the Paris agreement’s temperature target would entail for nature. So, for the first time, we studied the consequences of allowing Earth’s temperature to exceed these precautionary limits, then fall below them again, for marine and land-based life. In other words, we looked at how damaging the journey of overshooting the 2°C temperature target would be, and not just the destination itself.