In News

• The new annual State of the Climate report, published recently by the World Meteorological Organisation (WMO) found that 2023 was the hottest year on record.

Major findings

• GREENHOUSE GASES- The unprecedented levels of GHGs in the atmosphere are the main culprit behind the rapid warming of the planet.
• Gases such as carbon dioxide, methane, and nitrous oxide trap the incoming solar radiation in the atmosphere and contribute to global warming.
• The concentration of aforementioned GHGs reached record-high observed levels in 2022 — the latest year for which consolidated global values are available (1984–2022).

SURFACE TEMPERATURE- The global average near surface temperature for 2023 spiked to 1.45 degree Celsius — the highest ever on record — above the pre-industrial levels.

• Although the rise in GHG concentrations in the atmosphere is the primary reason for soaring global temperatures, the onset of El Niño last year also contributed to the increase in mercury.
• El Niño refers to an abnormal warming of surface waters in the equatorial Pacific Ocean.
• It increased the likelihood that temperature records would be broken, and there would be more extreme heat in many parts of the world and the ocean.

Ocean heat content - As the oceans have absorbed nearly 90 per cent of the extra heat trapped by GHGs since 1971, they steadily become warmer and their heat content has increased.

• In 2023, the ocean heat content (OHC) — the total amount of heat stored by the oceans — reached its highest level in the 65-year observational record, according to the report.

MARINE HEAT WAVES- Due to warmer temperatures, the global ocean experienced an average daily marine heatwave (MHWs) coverage of 32%, well above the previous record of 23% in 2016.

• MHWs occur when the surface temperature of a particular region of the sea rises to 3 or 4 degree Celsius above the average temperature for at least five days.

ANTARCTIC SEA-ICE EXTENT- Antarctic sea-ice extent plummeted to 1.79 million km2 in February 2023 — a new record low since the satellite era began in 1979.

• The extent remained at a record low for the time of year from June till early November, according to the WMO report.
• The annual maximum in September was 16.96 million km2, roughly 1.5 million km2 below the 1991–2020 average and 1 million km2 below the previous record low maximum.

GLACIER- In the hydrological year 2022-2023, the global set of reference glaciers suffered the largest loss of ice on record. Glaciers in North America and Europe were particularly impacted.

• According to the WMO report, the annual mass balance — the amount of mass gained or lost by the glacier and expressed in metres of water equivalent (m w.e.) — of the reference glaciers dropped to a new low in 2022-2023, which was –1.2 m w.e.

Source- Indian Express