Greenhouse gas concentrations, global sea levels and ocean heat content all reached record highs in 2021, a study published on Wednesday showed.
The US National Oceanic and Atmospheric Administration (NOAA) led hundreds of global scientists in an annual review of the changing climate.
Researchers found that seas around the globe rose 4.9 millimetres above 2020 levels, the 10th consecutive annual increase. This marks a cumulative 97mm rise over 1993, when records began.
The findings support recent research stating that sea-level rise is “locked in” due to the melting of the Greenland Ice Sheet and the NOAA reporting that levels along US coastlines could rise by up to 50 centimetres by 2050.
“The data presented in this report are clear — we continue to see more compelling scientific evidence that climate change has global impacts and shows no sign of slowing,” said NOAA Administrator Rick Spinrad.
Global ocean heat content, measured from the ocean’s surface to a depth of more than 1,800 metres, continued to increase and reached new highs in 2021, the NOAA said.
The report also found greenhouse gases reached record levels last year.
Carbon dioxide emissions seen in 2021 were the “highest measured in the modern observational records as well as the highest in at least the last million years based on paleoclimatic records”, the report said.
The study showed that 2021 was among the top six warmest years recorded since the 1800s. The past seven years have been the hottest in history.
“With many communities hit with 1,000-year floods, exceptional drought and historic heat this year, it shows that the climate crisis is not a future threat but something we must address today,” Mr Spinrad said.