What's the Worst That Couild Happen?

How bad could climate change get?

Humans have already warmed the planet by at least 1 degree Celsius by burning fossil fuels that spew heat-trapping gases into the sky. The oceans are rising, and deadly disasters like wildfires, heat waves, and flooding are becoming more destructive. Almost every part of the world is experiencing the effects of climate change.

That much is “unequivocal,” according to the latest report from the Intergovernmental Panel on Climate Change (IPCC), an international team of scientists convened by the United Nations.

What’s far less certain is just how bleak the future of our planet will be.

This critical question reaches beyond physical sciences into economics, sociology, and even psychology. Humans still have the power to slow the climate crisis — though with each day that goes by without sweeping societal changes to slash emissions, the outlook grows more grim.

The first installment of the IPCC’s sixth assessment report, which focuses on the physical science behind climate change, considers five scenarios that game out how humanity will respond, or not, to the specter of warming. They reveal that some of the more extreme projections of the past are less likely to come to fruition. But every scenario in the report also overshoots one of the targets of the 2015 Paris climate agreement. A best-case scenario now requires drastically more climate action than the world has achieved to date, and the window for action is closing.

However, “Scenarios are not predictions,” the report says. “Instead, they provide a ‘what-if’ investigation of the implications of various developments and actions.”

In short, these scenarios show how scientists are grappling with the capriciousness of human behavior. What happens if more countries are taken over by nationalists? Or if clean technology makes a radical leap forward? Or if countries and corporations actually start to buckle down and throttle emissions?

Our planet has many possible futures that depend on human decisions. These visions of tomorrow emphasize that we have profoundly and irreversibly changed the world, but also that much of the potential warming is still in our hands.  READ MORE