The global climate in 2015–2019

Compared to the previous five-year assessment period 2011–2015, the current five-year period 2015–2019 has seen a continued increase in carbon dioxide (CO2) emissions and an accelerated increase in the atmospheric concentration of major greenhouse gases (GHGs), with growth rates nearly 20% higher. The increase in the oceanic CO2 concentration has increased the ocean’s acidity.

This report finds that the five-year period 2015–2019 is likely the warmest of any equivalent period on record globally, with a 1.1°C global temperature increase since the pre-industrial period and a 0.2°C increase compared to the previous five-year period.

The report reveals that more heat is being trapped in the ocean; 2018 had the largest ocean heat content values on record measured over the upper 700 meters. Precipitation has increased in some regions and decreased in others. Heatwaves were the deadliest meteorological hazard in the 2015–2019 period, affecting all continents and resulting in new temperature records in many countries, accompanied by unprecedented wild fires that occurred in particular in Europe, North America and other regions. The 2019 northern summer saw record-breaking wild fires that expanded to the Arctic regions, setting new records, and wide-spread fires in the Amazon rainforest.