Climate change made the past 7 years the warmest on record

The UN’s World Meteorological Organization found that 2021 was the seventh hottest year to date, at 1.11°C above pre-industrial levels

By Adam Vaughan

The past seven years were the warmest on record as climate change continued apace, despite the cooling effect of the La Niña weather pattern in 2021, the United Nations has found.

The UN’s World Meteorological Organization (WMO) analysed the six main global temperature data sets, which revealed that last year was the seventh hottest to date, at 1.11°C above pre-industrial levels.

“The continued onslaught of record years, including the seven warmest having occurred since 2015, is precisely what we expect to see due to human-caused planetary warming,” says Michael Mann at Pennsylvania State University.

Governments at the COP26 climate summit in November reaffirmed their commitment to trying to hold temperature rises to 1.5°C and well below 2°C at worst. But emissions reductions pledges currently have the world on course for 2.4°C or more. 2021 is the seventh year in a row where temperatures have been more than 1°C above pre-industrial levels.

While only the seventh warmest year on average globally, 2021 saw climate scientists shocked by several temperature records broken by much larger margins than usual in some places, such as the near-50°C record set in Lytton, Canada. Previous research showed this event would have been “virtually impossible” without climate change.

“Climate change impacts and weather-related hazards had life-changing and devastating impacts on communities on every single continent,” said Petteri Taalas at the WMO in a statement.

Although not a record for surface air temperatures, 2021 was another record-breaking year for heat content in the upper levels of the oceans, which are absorbing much of the carbon dioxide emitted by humans and the heat that this gas traps.

The cooling effect of the La Niña weather pattern is expected to give way later this year to its opposite, El Niño, which was responsible for 2016 being the hottest year on record. The UK Met Office, which holds one of the six data sets examined by the WMO, forecasts that 2022 will be 1.09°C above pre-industrial levels.

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