By 2020, warming rates should eclipse historical bounds of the past 1,000 years — and likely at least 2,000 years — and keep rising. If greenhouse gas emissions continue on their current trend, the rate of warming will reach 0.7°F per decade and stay that high until at least 2100.
The northern hemisphere will be the first region to experience historically unprecedented warming. The Arctic, which is already the fastest warming part of the planet, will see temperatures rise 1.1°F per decade by 2040. North America and Europe will see slightly lower, though equally unprecedented, warming.
“With those high rates of change, there’s not going to be anything close to equilibrium,” Smith said, underscoring the profound potential impacts on both the natural world and society.
“The authors have demonstrated that we are currently headed into uncharted waters when it comes to the rate of climate change we are now seeing,” Michael Mann, who runs Penn State’s Earth System Science Center, said. “While past studies have focused on the unprecedented nature of the current warmth in the context of the past millennium, there has been less attention to the equally — if not more — critical issue of the rate of warming.”