In Short : Global warming could breach the critical 1.5-degree Celsius threshold in 2024. The outcome hinges on factors like emissions, climate policies, and natural variability. Stay informed by checking the latest climate assessments and reports from reputable research organizations.
In Detail : At the 2015 UN climate change conference, the international community agreed to make efforts to limit global warming to 1.5 degrees celsius above pre-industrial levels. Since then, global temperatures have continued to rise, with record-breaking temperatures in 2023. The UK’s Met Office has projected that 2024 could be even warmer, with the 1.5-degree threshold temporarily exceeded. This briefing summarises the background to the 1.5-degree threshold, and what actions the UK government is taking to mitigate the impacts of climate change.
1. What is the 1.5-degree celsius threshold, and could it be breached in 2024?
1.1 The 1.5-degree celsius threshold
The method used by the UN’s Intergovernmental Panel on Climate Change (IPCC) to measure levels of global warming is to compare average global temperatures to the average temperatures in the pre-industrial period (1850–1900).[1] It is measured as an average across long timeframes (30 years) and across temperatures over land and ocean. Long-term temperature rises over 1.5 degrees celsius are projected to result in various risks to natural and human systems, including more extreme weather events, sea level rises, risks to marine and terrestrial ecosystems, and risks to human health and wellbeing.
In 2015, the United Nations COP21 climate change conference was held in Paris, France. A central aim of the conference agreement (known as the ‘Paris agreement’) was to strengthen the global response to climate change by:
Keeping a global temperature rise this century well below two degrees celsius above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 degrees celsius.
The Paris agreement is a legally binding international treaty. It entered into force in November 2016.[4]
The IPCC’s most recent assessment of the scientific evidence on climate change, ‘Climate change 2023: Synthesis report’, concluded that:
Human activities, principally through emissions of greenhouse gases, have unequivocally caused global warming, with global surface temperature reaching 1.1°C above 1850–1900 in 2011–2020.
Although the IPCC noted that the international community had made progress in implementing emissions reductions, it stated that “current mitigation and adaptation actions and policies are not sufficient”.[6] It said that projected global greenhouse gas emissions by 2030 meant it was “likely that warming will exceed 1.5°C during the 21st century and would make it harder to limit warming below 2°C—if no additional commitments are made or actions taken”.
1.2 Temperature records in 2023 and projections for 2024
There were record-breaking global temperatures in 2023 and it has been projected that 2024 could be even warmer. The EU’s Copernicus Earth observation programme stated that:
Unprecedented global temperatures from June onwards led 2023 to become the warmest year on record—overtaking by a large margin 2016, the previous warmest year.[7]
Copernicus listed a range of ‘temperature highlights’ in 2023, which included:
2023 is confirmed as the warmest calendar year in global temperature data records going back to 1850.
Global average sea surface temperatures remained persistently and unusually high.
2023 was remarkable for Antarctic sea ice: it reached record low extents for the corresponding time of the year in eight months [of the year]. Both the daily and monthly extents reached all-time minima in February 2023.
A large number of extreme events were recorded across the globe, including heatwaves, floods, droughts and wildfires.[8]
Copernicus also estimated that it was “likely that a 12-month period ending in January or February 2024 will exceed 1.5°C above the pre-industrial level”.
The UK’s Meteorological Office (the Met Office) has also projected that global temperatures could temporarily exceed the 1.5°C threshold in 2024.[9] It said that “2024 will be a further record-breaking year, expected to exceed 2023”. The Met Office pointed out that the spike in global temperatures in 2023 was given a “temporary and partial boost by the current El Niño event warming the tropical Pacific”. However, Professor Adam Scaife at the Met Office stated that the “main driver for record-breaking temperatures is the ongoing human-induced warming since the start of the industrial revolution”. Regarding 2024, the Met Office said:
The average global temperature for 2024 is forecast to be between 1.34°C and 1.58°C (with a central estimate of 1.46°C) above the average for the pre-industrial period.[10]
The Met Office’s Dr Nick Dunstone, who led the forecast, stated:
The forecast is in line with the ongoing global warming trend of 0.2°C per decade, and is boosted by a significant El Niño event. Hence, we expect two new global temperature record-breaking years in succession, and, for the first time, we are forecasting a reasonable chance of a year temporarily exceeding 1.5°C.[11]
Dr Dunstone added that it was “important to recognise that a temporary exceedance of 1.5°C won’t mean a breach of the Paris agreement”. The Paris agreement target is based on longer-term average temperatures. However, Dr Dunstone concluded that “the first year above 1.5°C would certainly be a milestone in climate history”.
2. What is the UK government doing to mitigate the impacts of climate change?
2.1 UK net zero targets
In 2019, the UK committed itself to reach net zero greenhouse gas emissions by 2050.[12] This target was made legally binding by the Climate Change Act 2008 (2050 Target Amendment) Order 2019. The government has also committed to cutting greenhouse gas emissions by at least 68% by 2030 compared to 1990 levels.
In June 2023, the UK’s independent statutory advisory body, the Climate Change Committee (CCC), published its ‘2023 progress report to Parliament’. The CCC concluded it was less confident the UK was on track to achieve its net zero target than it had been the previous year. The CCC argued the government lacked “urgency” in implementing its planned green energy transition. It also argued the UK needed to regain a clear international leadership role on climate. For further information on the CCC’s assessment of the government’s international actions to mitigate climate change, see section 2.2 below.
On 20 September 2023, the prime minister, Rishi Sunak, gave a speech setting out what he described as the government’s “new approach to achieving net zero”.[13] Mr Sunak argued the government’s recent approach did not account for additional costs to households and disruption to people’s lives. He said net zero measures risked “losing the consent of the British people” and that therefore the government would adopt a “more pragmatic, proportionate, and realistic approach […] that eases the burdens on working people”.
Mr Sunak said his government remained committed to meeting its net zero targets. However, he said this could be achieved in a “fairer, better way” by changing the following policies. He announced the government would:
Push back the planned date for phasing out the sale of new petrol and diesel cars and vans from 2030 to 2035.
Delay the planned date for phasing out the installation of new oil and liquefied petroleum gas (LPG) boilers and new coal heating for off-gas grid homes from 2026 to 2035. The government has announced it intends to consult on options for the decarbonisation of off-grid properties in 2024.
Increase the cash grants available as part of the government’s boiler upgrade scheme by 50% to £7,500.
Exempt some households from the requirement to phase out fossil fuel boilers, including gas.
Reverse the plans to introduce a new requirement for landlords to upgrade the energy efficiency of their properties
The CCC published a response to Mr Sunak’s announcement on 12 October 2023.[14] The committee said it remained concerned about the likelihood of the UK meeting its net zero targets. It also criticised the government, saying the recent policy changes had not been accompanied by estimates of their potential effect on emissions or evidence supporting the government’s claim that the UK’s overall net zero targets could still be met.
Al Gore, former US vice-president and climate campaigner, said the announcements in Mr Sunak’s speech were “shocking and disappointing” and were “not what the world needs from the UK”. The shadow secretary of state for climate change and net zero, Ed Miliband, also criticised the policy changes, accusing the government of “dither and delay”.