5 min readNew DelhiSep 9, 2023 07:00 AM IST
First published on: Sep 9, 2023 at 07:00 AM IST
Raging wildfires across Europe and Canada. Devastating floods, cloudbursts, and storms in China, India and Brazil. Sweltering heat waves in numerous countries.
The recent extreme weather events leave little to no doubt that the climate crisis is here. As a result, numerous climate records on temperature, ocean heat, and Antarctic sea ice cover are getting smashed week after week.
“Global temperature records continue to tumble in 2023… The scientific evidence is overwhelming, we will continue to see more climate records and more intense and frequent extreme weather events impacting society and ecosystems, until we stop emitting greenhouse gasses,” Samantha Burgess, deputy head of European Union’s Copernicus Climate Change Service (C3S), said recently. Here are three such records broken in the summer of 2023 and why they matter.
1. Hottest summer ever
This year’s summer was the hottest on record, C3S and the World Meteorological Organization (WMO) said on Wednesday (September 6). The three-month period from June to August broke previous records with an average temperature of 16.77 degree Celsius, which was 0.66 degree Celsius above the 1990-2020 average.
Global-mean surface air temperatures for the 30 warmest boreal summers (June-July-August) in the ERA5 data record, ranked from lower to higher temperature. Data: ERA5. Credit: C3S/ECMWF.
Last month was the warmest August on record and the second hottest ever month after July 2023, according to the data presented by C3S and WMO. It also showed that the average temperature in August was 16.82 degree Celsius — 0.71 degree Celsius more than the 1991-2020 average.
In July, the global average daily temperature crossed the mark of 17 degree Celsius for the first time. While on July 3, the average temperature reached 17.01 degree Celsius, on July 6, mercury soared to 17.08 degree Celsius. The latter is currently the hottest day recorded on the planet.
Why it matters: With such soaring temperatures and El Nino conditions setting in, the year 2023 may become the warmest ever in history. It so far the second-hottest on record — only 0.01 degree Celsius below the all-time high of 2016.
The development highlights the possibility that the planet may soon become 1.5 degree Celsius warmer than it was during the pre-industrial times. Once the limit is breached, there could be irrevocable damage to the Earth’s ecosystem, severely impacting humans and other living beings.
2. Highest sea surface temperature
Global average sea surface temperature is also off the charts. Each day from July 31 to August 31, 2023, has witnessed warmer global average sea surface temperature than the previous record from March 2016. Therefore, August as a whole saw the highest global monthly average sea surface temperature on record across all months, at 20.98 degree Celsius — it is well above average for August, with an anomaly of 0.55 degree Celsius, C3S said.
Daily global sea surface temperature average plotted as a time series for each year from 1 January 1979 to 31 August 2023. The years 2023 and 2016 are shown with thick lines shaded in bright red and dark red, respectively. Data: ERA5. Credit: C3S/ECMWF.
Notably, the North Atlantic Ocean’s average sea surface temperature reached a new high on August 31, when it touched 25.19 degree Celsius.
Why it matters: The oceans have absorbed 90% of the additional heat caused by human activity since the second half of the 19th Century. Higher ocean temperatures often cause marine heat waves (MHWs), which are extreme weather events.
MHWs lead to the deaths of several marine species, alter their migration patterns, cause coral bleaching and even impact weather patterns. They also can make storms like Hurricanes and Typhoons stronger.
3. Lowest Antarctic sea ice extent
The Antarctic sea ice extent hit a new record low in 2023. In July, the sea ice extent averaged 13.5 million sq km, the lowest levels observed for this time of year since the continuous satellite record began in late 1978, a NASA Earth Observatory report said.
Left: Average Antarctic sea ice concentration for August 2023. The thick orange line denotes the climatological ice edge for August for the period 1991-2020. Right: Antarctic sea ice concentration anomaly for August 2023 relative to the August average for the period 1991-2020. Data source: ERA5. Credit: Copernicus Climate Change Service/ECMWF.
August was no better as the monthly value for sea ice cover was 12% below average — by far the largest negative anomaly for August on record, according to C3S. The worst affected regions were the northern Ross Sea and in the South Atlantic and Indian Ocean sectors.
Why it matters: The extreme decline in Antarctica’s sea ice sheet has set alarm bells ringing for scientists. Less ice cover may have grave consequences for the world. Low sea ice extent leads to higher ocean temperatures, difficulty in the formation of ice, rising sea levels, and disruption of the ocean circulation.
Residents watch part of the Sheep Fire wildfire burn through a forest on a hillside near their homes in Wrightwood, California, US June 11, 2022. (Photo: Reuters/Kyle Grillot/File) 
Global-mean surface air temperatures for the 30 warmest boreal summers (June-July-August) in the ERA5 data record, ranked from lower to higher temperature. Data: ERA5. Credit: C3S/ECMWF.
Daily global sea surface temperature average plotted as a time series for each year from 1 January 1979 to 31 August 2023. The years 2023 and 2016 are shown with thick lines shaded in bright red and dark red, respectively. Data: ERA5. Credit: C3S/ECMWF.
Left: Average Antarctic sea ice concentration for August 2023. The thick orange line denotes the climatological ice edge for August for the period 1991-2020. Right: Antarctic sea ice concentration anomaly for August 2023 relative to the August average for the period 1991-2020. Data source: ERA5. Credit: Copernicus Climate Change Service/ECMWF.
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