Context

• Europe’s Copernicus Climate Change Service (C3S) has announced that 2023 was the warmest year since records began in 1850, beating the previous record of 2016.
• The announcement said temperatures in 2023 likely exceeded those of any year-long period in at least the last 100,000 years.

Findings of C3S

• Last year was 1.48 degree Celsius warmer than the average of the 1850-1900 pre-industrial level and 0.17 degree Celsius warmer than 2016.
  • Rising temperatures contributed to a large number of extreme weather events around the world in 2023, including heatwaves, floods, droughts, and wildfires. 
• Global daily average sea surface temperature (SST) also went off the charts. Since mid-March 2023, the daily average SST has been the highest ever. 
  • It led to marine heatwaves in the Mediterranean, the Gulf of Mexico and the Caribbean, the Indian Ocean and the North Pacific, and much of the North Atlantic.
• Sea ice extent in Antarctica plummeted to a new low. In September, it reached an annual maximum 16.96 million sq km, which was 1.03 million sq km less than the previous record low set in 1986.

Why was it so hot?

• The main driver behind the extreme warming is the increasing greenhouse gas concentrations in the atmosphere. 
• Greenhouse gases like carbon dioxide and methane, and water vapour trap the Sun’s energy in the Earth’s system before it escapes to space, causing warming.
• In 2023, greenhouse gas concentrations reached the highest levels ever recorded in the atmosphere.
• The onset of El Niño last year, after seven years, played a role. 
  • 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.

What could happen now?

• Scientists have suggested that 2024 could be warmer than even 2023. Typically, in the past few decades, very hot years have been ones that began in an El Niño state. 
• Last year, El Niño didn’t set in until around July, which means that it wasn’t the primary reason behind the abnormal heat at that point. Therefore, 2024 could be hotter than last year. 
• It is also possible that the next year may surpass the 1.5 degree Celsius warming threshold across the entire calendar year for the first time. 
• The World Meteorological Organisation (WMO) in its 2023 State of Global Climate report said there was a 66% chance that at least one of the years between 2023 and 2027 would cross the threshold.

Impacts

• A long-term breach of the 1.5 degree limit would unleash far more severe climate change impacts, including more frequent and severe droughts, heatwaves, and rainfall. 
• To prevent this, the world needs to urgently implement certain steps, including greenhouse gas emission cuts, which it has failed to do so far.