Global 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.
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, they 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, they looked at how damaging the journey of overshooting the 2°C temperature target would be, and not just the destination itself.
The results suggest that a temporary overshoot would cause waves of irreversible extinctions and lasting damage to tens of thousands of species. This is what the world can expect if humanity fails to make deep emission cuts this decade, and relies instead on future technologies to remove emissions later.
Just a few years of global temperatures above 2°C could transform the world’s most important ecosystems.
The consequences of this exposure could be irreversible and include the tropical forest turning into savanna. The world would lose a critical global carbon sink, leaving more planet-warming gases in the atmosphere.