When almost 200 nations signed the Paris climate agreement in 2015, they pledged to keep Earth's average temperature to no greater than 1.5 degrees Celsius above pre-industrial levels.
Now a recent study in the journal Nature Climate Change reveals that the 1.5 degree threshold is effectively out of reach at this point, and 1.6 degrees is the best humanity can likely hope to achieve. Climate change is spiraling out of control and emissions from burning fossil fuels aren't dropping fast enough. The researchers arrived at this conclusion after modeling different emission scenarios through 2023, one that included "alternative scenarios with institutional, geophysical and technological feasibility constraint."
The scientists learned that even within all but the most ambitious projections regarding limiting greenhouse gas emissions, humans still fail to fall below the 1.6 degrees Celsius threshold. Given the feasibility constrains involved in those more ambitious agendas, however, the scholars also argue those outcomes remain very unlikely.
"Accelerated energy demand transformation can reduce costs for staying below 2º C but have only a limited impact on further increasing the likelihood of limiting warming to 1.6 °C," the authors write, alluding to the need to transition to carbon neutral energy technologies.
Speaking to Salon last month — when it was announced that humanity had reached 1.5 degrees Celsius above pre-industrial levels for 13 consecutive months — one climate change expert emphasized that this benchmark carries significant in real-world consequences.
"A year above 1.5C is unprecedented in human history," Dr. Ken Caldeira, an atmospheric scientist at the Carnegie Institution for Science's Department of Global Ecology, said. "Nevertheless, it is important to remember that each carbon dioxide emission causes another increment of global warming and so each emission avoided is an increment of global warming avoided."
