What does ’12 years to act on climate change’ (now 11 years) really mean?
We’ve been hearing variations of the phrase “the world only has 12 years to deal with climate change” a lot lately.
Sen. Bernie Sanders put a version of it front and center of his presidential campaign last week, saying we now have “less than 11 years left to transform our energy system away from fossil fuels to energy efficiency and sustainable energy, if we are going to leave this planet healthy and habitable.”
But where does the idea of having 11 or 12 years come from, and what does it actually mean?
The number began drawing attention in 2018, when the United Nations’ Intergovernmental Panel on Climate Change released a report describing what it would take to keep global temperatures from rising more than 1.5 degrees Celsius, a goal of the Paris climate agreement. The report explained that countries would have to cut their anthropogenic carbon dioxide emissions, such as from power plants and vehicles, to net zero by around 2050. To reach that goal, it said, CO2 emissions would have to start dropping “well before 2030” and be on a path to fall by about 45 percent by around 2030 (12 years away at that time).
Mid-century is actually the more significant target date in the report, but acting now is crucial to being able to meet that goal, said Duke University climate researcher Drew Shindell, a lead author on the mitigation chapter of the IPCC report.
“We need to get the world on a path to net zero CO2 emissions by mid-century,” Shindell said. “That’s a huge transformation, so that if we don’t make a good start on it during the 2020s, we won’t be able to get there at a reasonable cost.” [Continue reading…]
