NUNZIUM

The Paris Agreement is a legally binding international treaty on climate change. It was adopted by 196 Parties at COP 21 in Paris, on 12 December 2015 and entered into force on 4 November 2016. Its goal is to limit global warming to well below 2, preferably to 1.5 degrees Celsius, compared to pre-industrial levels. A study published on September 8 on Science highlights the importance of such objectives: by reviewing historic records and more than 200 peer-reviewed works, scientists determined that multiple climate tipping points could be triggered if global temperature rises beyond 1.5°C above pre-industrial levels. By “tipping point” is meant the minimum amount of warming that might trigger a catastrophic shift in a system. The team found that at the current level of global warming - 1.1°C since the preindustrial era - Earth has already passed the low-end risk estimate for five tipping points, putting coral reefs, permafrost, and polar ice at risk. For polar ice sheets, however, the authors estimate that 1.5°C is the more likely tipping threshold, and that the sheets might be able to withstand as much as 3°C of warming without irreversible decline. Despite the study also indicates that a lot of really bad tipping points are still avoidable, lead author David Armstrong McKay from Stockholm Resilience Centre, University of Exeter, and the Earth Commission says that “the chance of crossing tipping points can be reduced by rapidly cutting greenhouse gas emissions, starting immediately”.