Concentrations of greenhouse gases, particularly CO2, continue to rise. The year 2019 ended with a global average temperature of 1.1 °C above estimated pre-industrial averages, second only to the record set in 2016. Without the role of El Niño in the warming increase observed in 2016, 2019 would have been a record year.
Temperature is one indicator of the ongoing climate change. Also, sea levels are rising at an increasing pace, through greater warming of the oceans, on the surface and in the depths, and through the enhanced melting of Greenland’s ice and of glaciers, exposing coastal areas and islands to a greater risk of flooding and the submersion of low-lying areas.
Furthermore, in 2019, heatwaves, combined with long periods of drought, were linked to wildfires of unprecedented size. This was the case in Australia, where millions of hectares were set ablaze, and in Siberia and other Arctic regions hit by wildfires of record intensity.
Besides these powerful phenomena, there has been weather-related damage, such as the effects of multi-annual droughts on the internal and cross-border migration of populations, greater exposure of the world population to health hazards due to heat and pollution, and the reduction of economic growth, especially in developing economies, due to rising temperatures and weather extremes.
The results of this report demonstrate that climate change is already very visible in various ways. More ambitious climate mitigation efforts are needed to keep the warming below 2 °C by the end of the century.