Within the next five years, the world is likely to experience at least one year in which the global average surface temperature exceeds 1.5C above pre-industrial levels. That was the stark prediction of the World Meteorological Organisation (WMO) this week, in its climate forecast.
Straying beyond 1.5C could lead to potentially irreversible effects on the global climate system, scientists have warned, including the collapse of the Greenland and West Antarctic ice sheets, the abrupt melting of permafrost, rising sea levels and bleaching coral reefs. For these reasons, the 1.5C limit is at the heart of the 2015 Paris climate agreement, which bound countries to hold global temperature rises “well below 2C” and “pursuing efforts” to 1.5C.
