2023 is almost certain to be the warmest year on record, as October is confirmed as the 5th month in a row of record-breaking global temperatures. June, July, August and September all saw previous high temperature records outstripped.
October continued an extended run of high land and sea surface temperatures and low sea ice, according to a recent announcement from the European Union’s Copernicus Climate Change Service.
We asked climate scientists at the National Centre for Atmospheric Science based at the University of Reading to explain the global climate conditions, why they are happening, and what they think about it.
Another month, another unprecedented record. The consequences are all too clear: floods, heatwaves and storms, all made worse by climate change and our reliance on burning fossil fuels. We already have many of the solutions to wean ourselves off this deadly addiction, but only if different choices are made to confront this issue now, rather than delaying actions and committing the world to even worse consequences.
Professor Ed Hawkins, a climate scientist at the National Centre for Atmospheric Science based at the University if Reading
Why are climate records being broken?
The Copernicus Climate Change Service reported that it was by far the warmest October on record globally, with an average surface air temperature of 15.3°C.
October 2023 was 0.85°C above the 1991-2020 average, and 0.4°C above the previous warmest October in 2019. The average sea surface temperature for October was also the highest of record globally for October.
In October 2023, rainfall was above average across most of Europe – with Storm Babet and Storm Aline impacting northern Europe and southwestern Europe respectively.
October 2023 saw Arctic sea ice extent reach its 7th lowest value for this time of year, and it was also the 6th consecutive month that Antarctic sea ice extent remained at record low levels.
While it may not seem like large changes, last month’s records are significant.
October’s record-breaking temperatures are driven primarily by human-caused climate change. Scientists are also investigating the role of regional climate and weather, ocean circulation, and El Niño.
El Niño is an irregular climate pattern occurring every 2-7 years, which causes warming of surface and subsurface waters in the eastern and central tropical Pacific Ocean. In turn this warming affects atmospheric circulation and influences global climate, meaning El Niño can warm the planet significantly (up to about 0.2°C averaged over a given year).
Climate change means the background temperature of the planet is warmer, meaning periods of hot weather are likely to be more frequent and more intense – leading to unparalleled temperatures being recorded.
Will 2023 be the warmest year on record?
2023 is anticipated to be the warmest year on record after numerous temperature records have been broken over recent months. Global temperatures may increase even further above average as El Niño continues to grow before peaking during December to January.
This year alone has seen numerous extreme weather events, record-breaking sea surface temperatures, and a record low Antarctic sea ice extent.
For example, since April 2023 the sea-surface temperature in the North Atlantic has been considerably higher than any previous year – including in the seas around the UK. In the Southern Hemisphere, since May and throughout the winter season, the sea-ice extent around Antarctica has been substantially smaller than in any of the 40 previous years.
As climate change continues, these events are expected to become more extreme or occur much more frequently. Earth is warming at a rate that is unprecedented in the history of human civilisation.
The average temperature at the Earth’s surface has risen by 1.2°C since the pre-industrial period, and 19 of the top 20 warmest years on record have occurred after 2000.
The sizzling October 2023 is another example that shows how temperature records are getting shattered by a humongous margin. Global warming due to increased greenhouse gas emissions and El Niño in the tropical Pacific Ocean are hitting the planet really hard. It is frightening to see that the global temperature since June 2023 is much warmer than that during the second half of 2015 when El Niño was much stronger. Our planet continues to pass through unfortunate milestones in its meteorological history, and it won’t be surprising to see new records in subsequent months.
Dr Akshay Deoras, a research scientist at the National Centre for Atmospheric Science based at the University of Reading
What about the Paris Agreement and COP28?
Every additional 0.1°C of warming makes climate change worse. In pursuit of curbing dangerous levels of temperature rise, the Paris Agreement has set a goal of holding the increase in global average temperature to well below 2°C above pre-industrial levels – and to aim for 1.5°C.
According to the Copernicus Climate Change Service, the months of July, August, September, and October in 2023 have all been more than 1.5°C warmer than the pre-industrial reference period.
The recent 5-month run of record-breaking global temperatures starkly illustrates the global temperature extremes in 2023, but should not be misinterpreted to mean the Paris Agreement has been breached.
Breaking the 1.5°C – 2°C global warming threshold refers to long-term annual average global surface temperatures, not individual months.
Assuming that no drastic greenhouse gas emission reductions are implemented in the coming years, the planet is expected to overshoot 1.5°C global warming in the mid-2030s – in around 12 years from now.
It is widely anticipated by climate scientists and the United Nations’ Intergovernmental Panel on Climate Change that breaching the 1.5°C threshold will mean much more severe climate and weather extremes and large-scale damaging impacts.
The 2023 United Nations Climate Change Conference, commonly referred to as COP28, will take place in late November and bring governments together to discuss how to limit and prepare for future climate change.