Recent assessments from the World Meteorological Organization (WMO) indicate that the world is approaching 1.5°C of global mean surface temperature warming faster than previously anticipated. Individual years above 1.5°C of warming have already occurred, and there is now a high probability that temporary exceedances will become increasingly common during the remainder of this decade.
The focus of climate science is shifting from asking whether 1.5°C will be exceeded to:
- understanding when 1.5 °C will be reached
- understanding how long an overshoot of 1.5°C may last before greenhouse gas concentrations (and hence the global temperature) are brought back down
- understanding what the implications will be for societies and ecosystems
Current evidence suggests that sustained warming of 1.5°C above pre-industrial levels is likely to be reached during the late 2020s or early 2030s.
A global average warming of 1.5°C does not mean that all regions will warm uniformly. Land generally warms faster than oceans, and increases in the intensity of extreme weather, such as heatwaves or unusually heavy rainfall, exceed changes to mean warming. Higher-latitude regions such as the Arctic are warming fastest of all, at nearly four times faster than the global average. The UK has already warmed by approximately 1.3°C relative to the period 1961 to 1990, and is at increased risks from heatwaves, heavy rainfall and sea-level rise.
The 1.5°C global warming level should not be interpreted as a precise boundary between safe and dangerous climates. Rather, climate risks increase progressively with every increment of warming, and many impacts are already being experienced today.
Read the government’s full post on GOV.UK Understanding the 1.5°C global warming level: Implications for policy and adaptation – POST