The State of the Global Climate 2021, published by the World Meteorological Organization (WMO), was released this week. The report highlights four key climate change indicators that were at record levels in 2021 namely greenhouse gas levels, sea level rise, ocean heat and ocean acidification.

The WMO State of the Global Climate in 2021

This is my summary based on both the report as well as additional research to help explain each point:

  • Greenhouse gas levels are still rising. According to the report, Carbon Dioxide (Co2) reached 413.2 parts per million (ppm) globally or 149% pre-industrial levels which was about 278 ppm in the mid 1700s (WEF).

  • Sea level rise due to melting ice caps and land ice has increased almost 50% in the past 30 years. Between 2013 and 2021, sea level has risen an average of 4.5mm per year according to the report. Compared to the global mean sea level of 2.4mm per year observed in 1993, this is a big increase (Nature Climate Change).

  • Ocean heat reached a record high according to the report. As the temperature of the earth changes due to increased Co2, so does the ocean. The upper layers of the ocean continues to warm and is expected to get even warmer affecting deeper levels of the ocean. The report highlights that the ocean experienced at least one ‘strong’ marine heatwave in 2021.

  • Ocean acidification due to continued warming of the ocean has reached an unprecedented level in at least 26,000 years according to the report. The danger of the ocean absorbing more Co2 and warming up considerably could change the chemistry of the ocean and lower the average pH of the ocean, making it more acidic. This threatens ocean ecosystems and marine wildlife.

In addition to this, high-impact events in 2021 included drought, flooding, heatwaves, wildfires, hurricanes, tropical cyclones and severe storms which resulted in loss of lives, homes, livelihoods and massive economic losses.

World Meteorological Organization (WMO) Secretary-General Professor Petteri Taalas sums up the report in the following quote:

“Our climate is changing before our eyes. The heat trapped by human-induced greenhouse gases will warm the planet for many generations to come. Sea level rise, ocean heat and acidification will continue for hundreds of years unless means to remove carbon from the atmosphere are invented. Some glaciers have reached the point of no return and this will have long-term repercussions in a world in which more than 2 billion people already experience water stress.”

WMO Secretary-General Prof. Petteri Taalas
State of the Global Climate 2021 – Interview with Professor Petteri Taalas

To download the report:

Key references to check out:

  1. The Conversation:
  2. World Economic Forum:
  3. Nature Climate Change:

Photo Credit of Main Image: Annie Spratt via