WMO’s State of the Climate report

• Context (IE | DTE | DTE): On March 19, the World Meteorological Organization (WMO) released its annual State of the Climate report, which highlights significant climate trends and events.
• 2023 was reported as the hottest year on record, with multiple records broken across various climate indicators.
• These indicators include greenhouse gas levels (GHGs), surface temperatures, ocean heat, sea level rise, Antarctic Sea ice cover, and glacier retreat.

Greenhouse Gases

• GHG concentrations reached record-high levels in 2022, based on data from 1984 to 2022.
  • Greenhouse gases such as Carbon dioxide, methane, and nitrous oxide trap solar radiation, contributing to global warming.
• Among these gases, the rate of increase of methane was the second highest on record and the highest on record for nitrous oxide.

Surface Temperature

• In 2023, the global average temperature was 1.45 degrees Celsius higher than pre-industrial levels, marking a record high.
• Higher GHG levels, along with El Nio occurrences, contributed to the rise in temperature.

Ocean Heat Content

• Oceans have absorbed about 90% of the additional heat trapped by GHGs since 1971.
• This led to a steady increase in ocean temperatures and heat content.
• In 2023, ocean heat content reached its highest level in the 65-year observational record.

Marine Heat Waves

• Warmer temperatures caused a significant increase in global ocean heatwaves, with coverage reaching 32%.
• Marine heatwaves occur when surface temperatures of a particular region of a sea rise 3 or 4 degrees Celsius above average for at least five consecutive days.

Antarctic Sea-Ice Extent

• Antarctic sea-ice extent hit a record low of 1.79 million km2 in February 2023, the lowest since satellite records began. The extent remained at a record low from June to early November.
• In September, the annual maximum sea-ice extent was 16.96 million km2, which is 1.5 million km2, well below the average from 1991 to 2020.

Glacier

• During the hydrological year 2022-2023, the world’s reference glaciers experienced unprecedented ice loss. Glaciers in North America and Europe were severely affected.
• The annual mass balance of reference glaciers reached a new low of -1.2 m w.e. in 2022-2023.

Sea-level rise

• It also reached a record high in 2023 since 1993. This is due to continued ocean warming as well as the melting of glaciers and ice sheets.
• The rate of increase went up from 2.13 millimetres per year (mm/yr) from 1993 to 2002 to 4.77 mm/yr from 2014 to 2023.

Ocean Acidification

• The ocean absorbs approximately 25% of the yearly emissions of human-produced carbon dioxide.
• leading to ocean acidification, which harms marine life and ecosystems.
• The UN IPCC reported that ocean acidity is at its lowest in 26,000 years, but regional variations exist.
• The WMO emphasises that long-term, detailed observations are crucial for understanding and addressing ocean acidification’s impact.