Key climate change indicators break records in 2021

Geneva - Four key global climate change indicators, which are greenhouse gas concentrations, sea level rise, ocean heat and ocean acidification, set new records in 2021.

This is a clear sign 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, according to the World Meteorological Organisation (WMO).

Extreme weather led to hundreds of billions of dollars in economic losses and 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.

The latest WMO report confirmed the last seven years have been the warmest seven years on record.

Last year was only one of the seven warmest because of a La Niña event at the start and end of the year. This had a temporary cooling effect but did not reverse the overall trend of rising temperatures.

The average global temperature in 2021 was about 1.11Cdeg above the pre-industrial level. It is just a matter of time before the planet feels another warmest year on record, WMO secretary-general professor Petteri Taalas says.

The upper 2000m depth of the oceans continued to warm in 2021 and it is expected that it will continue to warm in the future, a change which is irreversible on centennial to millennial time scales.

Global sea levels reached a new record high in 2021, after increasing at an average 4.5mm per year over the period 2013 to 2021. This is a real concern for New Zealand.

The ozone hole over the Antarctic was unusually large and deep, reaching its maximum area of 24.8 million km2  (the size of Africa) as a result of a strong and stable polar vortex and colder than average conditions in the lower stratosphere.