Greenhouse Gas, Sea Level Rise and Ocean Heat Set New Records in 2021

Greenhouse gas concentrations, sea-level rise, ocean heat, and ocean acidification – the four key climate change indicators – set new records in 2021, with extreme weather causing hundreds of billions of dollars in economic losses, according to the WMO State of the Global Climate in 2021 report released on Wednesday.

"It wreaked a heavy toll on human lives and well-being and triggered shocks for food and water security and displacement that have accentuated in 2022. This is yet another clear sign that human activities are causing planetary-scale changes on land, in the ocean, and in the atmosphere, with harmful and long-lasting ramifications for sustainable development and ecosystems," the World Meteorological Organisation (WMO) said.

For six global temperature data sets, the annual mean temperature difference from pre-industrial conditions (1850-1900) is considered (1850-2021).

The World Meteorological Organization's State of the Global Climate in 2021 report confirmed that the previous seven years were the warmest seven years on record, with 2021 being "only" one of the seven warmest due to a La Nina event (ocean phenomenon in the Pacifics) at the start and end of the year.

This provided a brief cooling effect but did not reverse the overall trend of rising temperatures. In 2021, the average global temperature was 1.11 (plus or minus 0.13) degrees Celsius higher than the pre-industrial level.