2023 is the hottest year on record
It has been officially announced that 2023 is the hottest year ever due to human-caused climate change and the strengthening of the natural El Nino phenomenon.
Last year was 1.48 degrees Celsius warmer than average before humans started burning large amounts of fossil fuels, the EU climate service says.
BBC analysis shows that almost every day since July has seen a new rise in global air temperature for this time of year.
Sea surface temperatures also exceeded previous record levels.
Last week, the Meteorological Office in Britain announced that the United Kingdom will witness the second hottest year on record in 2023.
These global records bring the world closer to exceeding key international climate targets.
“What surprised me was not just that [2023] was record-breaking, but the degree to which it broke previous records,” says Andrew Dessler, a professor of atmospheric sciences at Texas A&M University.
An exceptional wave of heat
It is known that the world is now hotter than it was 100 years ago, as humans continue to release record amounts of greenhouse gases such as carbon dioxide into the atmosphere.
But 12 months ago, no major scientific body predicted that 2023 would be the hottest year on record, because of the complex way in which the Earth’s climate is changing.
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During the first few months of the year, a slight rise in temperatures was recorded for a few days. But then the world witnessed a remarkable series of daily records in the second half of 2023.
More than 200 days have seen a new daily temperature record for this time of year, according to a BBC analysis of data from the Copernicus Climate Change Service.
This recent temperature rise is mainly linked to the rapid transition of El Nino, as well as long-term human-caused temperature rises.
The El Nino phenomenon is a natural event in which warmer surface waters in the eastern Pacific Ocean release additional heat into the atmosphere.
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But air temperatures rose unusually early in this El Nino phase, with the full effects not expected until early 2024, after El Nino has reached its strongest.
This has left many scientists unsure exactly what is happening with the climate.
“This raises a bunch of really interesting questions about why [2023] will get hotter,” says Zeke Hausfather, a climate scientist at Berkeley Earth, a science organization in the United States.
The consequences are felt around the world
One of the other notable features of the rise in temperature in 2023 is that it will be felt largely around the world.
Almost the entire world saw temperatures warmer than levels between 1991-2020, a period that was itself about 0.9 degrees Celsius warmer than it was before humans started burning large amounts of fossil fuels in the late 1800s.
This record global temperature rise has helped exacerbate several extreme weather events in large parts of the world in 2023, from extreme heatwaves and wildfires across Canada and the United States, to prolonged drought and then floods in parts of East Africa.
“These are more than just statistics,” says Professor Petri Taalas, Secretary-General of the World Meteorological Organization between 2016 and 2023. “Extreme weather destroys lives and livelihoods on a daily basis.”
Air temperature is only one measure of the Earth’s rapidly changing climate. The year 2023 also witnessed:
* Sea ice in the Arctic Ocean has reached a low level, with Arctic sea ice extent also below average.
* Glaciers in western North America and the European Alps experienced an intense melting season, adding to sea level rise.
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* The world’s sea surface reached the highest temperature on record amid multiple marine heatwaves, including in the North Atlantic.
Warning for 2024 and beyond
2024 could be hotter than 2023, with some record ocean surface heat escaping into the atmosphere, although El Nino’s current “strange” behavior means it’s difficult to be sure, says Dr Hausfather.
This raises the possibility that 2024 will exceed the key warming threshold of 1.5°C over the entire calendar year for the first time, according to the UK Met Office.
Nearly 200 countries agreed in Paris in 2015 to try to limit warming to that level, to avoid the worst effects of global warming.
Noting that the agreement may take between 20-30 years, any change that occurs in 2024 does not mean that the agreement has gone unheeded. But it highlights the worrying direction in which things are heading, with increasing temperatures every year the world moves closer to exceeding 1.5°C in the long term.
Human activities are behind this global warming, although natural factors such as El Nino can raise or lower temperatures for certain years, and the temperatures witnessed in 2023 exceed natural causes.
We note that the years 1998 and 2016 were record-breaking years, supported by the high El Nino temperature. But these are nowhere near the new 2023 records.
“2023 was an exceptional year,” concludes Dr. Samantha Burgess, Deputy Director of the Copernicus Climate Change Service.
The latest warning comes shortly after the COP28 climate summit, where countries agreed for the first time on the need to address the main cause of rising temperatures, fossil fuels.
Although the wording of the agreement was weaker than many wanted, with no obligation for those countries to act, it is hoped that it will help encourage countries to invest more in areas such as renewable energy and electric cars.
The researchers say this could make a crucial difference to reducing the consequences of climate change, although it is likely to exceed the 1.5°C target.
Dr Frederic Otto, senior lecturer in climate science at Imperial College London, says: “Even if we end up at 1.6°C, that would be much better than giving up and ending up near 3°C, which is what current policies will bring us.”
