Climate change's worst-case scenario is officially canceled. The term "RCP 8.5" - the highest-emission scenario used by climate scientists to project the planet's future - has been formally retired. This shift represents real progress and hope, as the apocalyptic climate change future that we've been describing for 15 years is no longer on the table. Instead, a merely bad climate future - about 2.8°C by 2100 - is now the central scientific estimate. But even if we've averted doom, there is a lot of work to do to secure a safer future. The new "medium" climate pathway - the one that reflects current policies - estimates 2.8°C of warming on average by 2100, with the likely range running from 2.1°C to 3.7°C. That would still mean drastic declines in coral reefs and accelerated species extinction, worsening water scarcity, and further sea level rise. And as with anything to do with climate change, this scientific shift was quickly politicized. The day before Hausfather and his co-authors published their analysis of RCP 8.5’s retirement, President Donald Trump posted on Truth Social: "GOOD RIDDANCE!", and described the change as proof that climate science was "WRONG! WRONG! WRONG!" Not surprisingly, Trump is the one who is wrong here, but his mistake shows how easy it is to take the wrong lesson from the end of RCP 8.5. We shouldn't fall for it. The entire point of climate scenarios like RCP 8.5 was that there was no one certain future for climate change - only multiple possible futures. Whether or not RCP 8.5 was ever possible, the enormous advances in clean energy over the past 15 years are what made its retirement certain. Now we have new futures before us, waiting for what we do next.
