The state of the climate in 2021 BBC Future
After the turbulent year of 2020, BBC Future takes stock on the state of the climate at the beginning of 2021.
From unprecedented wildfires across the US to the extraordinary heat of Siberia, the impacts of climate change were felt in every corner of the world in 2020. We have come to a “moment of truth”, United Nations Secretary General Antonio Guterres said in his State of the Planet speech in December. “Covid and climate have brought us to a threshold.” BBC Future brings you our round-up of where we are on climate change at the start of 2021, according to five crucial measures of climate health.
- CO2 levels
The amount of CO2 in the atmosphere reached record levels in 2020, hitting 417 parts per million in May. The last time CO2 levels exceeded 400 parts per million was around four million years ago, during the Pliocene era, when global temperatures were 2-4C warmer and sea levels were 10-25 metres (33-82 feet) higher than they are now.
“We are seeing record levels every year,” says Ralph Keeling, head of the CO2 programme at the Scripps Institution of Oceanography, which has been tracking CO2 concentrations from the Mauna Loa observatory in Hawaii since 1958. “We saw record levels again this year despite Covid.”
The effect of lockdowns on concentrations of CO2 in the atmosphere was so small that it registers as a “blip”, hardly distinguishable from the year-to-year fluctuations of the carbon cycle, according to the World Meteorological Organization, and has had a negligible impact on the overall curve of rising CO2 levels.
“We have put 100ppm of CO2 in the atmosphere in the last 60 years,” says Martin Siegert, co-director of the Grantham Institute for climate change and the environment at Imperial College London. That is 100 times faster than previous natural increases, such as those that occurred towards the end of the last ice age more than 10,000 years ago.