Last December, the world came together in a rare scene of international unity. The genuinely groundbreaking Paris climate change agreement, signed by 195 nations, aimed to limit global warming to no more than 2°C (3.6°F) by 2100. Although just getting to this point is a remarkable achievement for our own species, some have argued that this is a rather arbitrary temperature limit – after all, how realistic is it that the world could stick to it?
A new Nature study has assessed the pledges made by the signatories of the Paris agreement, and it’s really not good news. The most likely scenario is that global temperatures will actually rise by 2.6°C to 3.1°C (4.7°F to 5.6°F) by 2100. Distressingly, the entire carbon budget for keeping to the 2°C (3.6°F) limit may actually be emitted by as soon as 2030.
“The Paris agreement… puts in place a flexible framework for a long-term transformation towards a low-carbon society,” Joeri Rogelj, a researcher at the International Institute for Applied Systems Analysis (IIASA), and lead author of the study, said in a statement. “But our analysis shows that these measures need to be strengthened in order to have a good chance of keeping warming to well below 2°C.”
The team of researchers conceived a variety of carbon emission scenarios based on pre-existing cutting-edge computer simulations, the most prominent of which assumed that Paris agreement pledges are enacted and continued after the year 2030, when the pledge period comes to an end. Clearly, humanity needs to be more ambitious at cutting greenhouse gas emissions than what’s already been agreed.
A variety of climate change scenarios, including the business-as-usual models (red), current climate change policy action not including the Paris agreement (yellow), the Paris pledge models (orange), and an extreme carbon footprint reduction model (blue). Symbols represent single computer simulation studies. Rogelj et al./Nature
The authors propose that far more stringent action is required after 2030, including roughly 3 to 4 percent reductions in global greenhouse gas emissions year-on-year. This, of course, is entirely possible. Just look at how China could start a wind power revolution, or how – if they keep their nuclear capabilities – many nations could mix nuclear and renewables to dramatically shrink their carbon footprint.