Greenhouse Gas Concentrations, Sea Level Rise Hits Record High

Emission reductions in the 11 high-income countries that have managed to

Greenhouse gas concentrations, global sea levels and ocean heat content hit new highs in 2021, which showed that climate change keeps surging ahead despite efforts to curb emissions, according to the 32nd annual State of the Climate report.

“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 NOAAAdministratorRick Spinrad. “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 as we work to build a Climate-Ready Nation — and world — that is resilient to climate-driven extremes.”


The international annual review, led by scientists from NOAA’s National Centers for Environmental Information and published by the Bulletin of the American Meteorological Society offsite link (AMS), is based on contributions from more than 530 scientists in over 60 countries. It provides the most comprehensive update on Earth’s climate indicators, notable weather events and other data collected by environmental monitoring stations and instruments located on land, water, ice and in space.

“The 2021 AMS State of the Climate provides the latest synthesis of scientific understanding of the climate system and the impact people are having on it,” said AMS Associate Executive Director Paul Higgins. “If we take it seriously and use it wisely, it can help us thrive on a planet that is increasingly small in comparison to the impact of our activities.”

  • The major atmospheric greenhouse gas concentrations — carbon dioxide, methane and nitrous oxide — each rose to new record highs during 2021. The global annual average atmospheric carbon dioxide concentration was 414.7 parts per million (ppm). This was 2.3 ppm greater than 2020 amounts. The annual average atmospheric methane concentration increase of 18 parts per billion (ppb) was the highest since measurements began. The annual increase of 1.3 ppb for nitrous oxide was the third highest since 2001, contributing to a global annual average atmospheric concentration of 334.3 ppb.
  • Annual global surface temperatures were 0.38 – 0.50 degrees F (0.21-0.28 of a degree C) above the 1991 -2020 average. This places 2021 among the six warmest years since records began in the mid to late 1800s. The last seven years (2015–2021) were the seven warmest years on record, and the average global surface temperature has increased at an average rate of 0.14 – 0.16 of a degree F (0.08 – 0.09 of a degree C) per decade.
  • Global ocean heat content, measured from the ocean’s surface to a depth of more than 6,000 feet, continued to increase and reached new record highs in 2021. For the 10th consecutive year, global average sea level rose to a new record high and was about 3.8 inches (97.0 mm) higher than the 1993 average — the year that marks the beginning of the satellite measurement record. 
  • La Niña conditions that began in mid-2020 continued for most of 2021. The annual global sea surface temperature in 2021 was lower than both 2019 and 2020 due in part to La Niña, but was still 0.52 of a degree F (0.29 of a degree C) higher than the 1991–2020 average. Approximately 57% of the ocean surface experienced at least one marine heat wave during 2021. La Niña contributed to the warmest year on record for New Zealand, but also to the coolest year since 2012 for Australia.
  • The Arctic had its coolest year since 2013, but 2021 was still the 13th warmest year in the 122 year record.
  • Tropical cyclone activity was well above average    


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