“Twelve years is at once an eternity and right around the corner. Just ask any parent watching their kids grow up. So it hits home when a growing chorus of often young voices — from proponents of the Green New Deal to the global Youth Climate Strike — says forcefully that the world has 12 years left to avoid disastrous climate change. This is just the latest dire warning about time running out issued over the past 20 years. But this deadline is different — it’s both entirely wrong, and oh so right.
The idea of a 12-year deadline arose last fall with the release of a special report of the Intergovernmental Panel on Climate Change. The United Nations group of climate scientists from around the world said that if the planet’s governments want to limit global warming to 2.7 degrees Fahrenheit (1.5 degrees Celsius) above preindustrial temperatures, a mere 1 degree Fahrenheit above today’s levels, society will have to reduce its greenhouse gas emissions by about half by 2030, declining further to net zero by around midcentury. The “about” and “around” typically get dropped in translation, rendering the outcome falsely precise, especially in headlines about the report. The Guardian, for example, announced: “We have 12 years to limit climate change catastrophe, warns U.N.”
Now, of course, it would be 11 years.
Technically, this deadline is wrong, not least because it is much too precise. The world won’t end in 2030 if emissions don’t decline. The NASA climate scientist Kate Marvel summed it up perfectly: “Climate change isn’t a cliff we fall off, but a slope we slide down.”
That’s one of the many reasons climate change is such a difficult problem. There’s no obvious stop sign, no simple red line. The reverse is also true: There won’t be a superhero ending to this movie, a point when climate change will have been “solved.” Our children and grandchildren — and theirs — will be managing the impacts of climate change for decades and centuries to come.”