Human-Induced Global Warming Is Increasing At 0.26°C Per Decade, The Highest Rate Since Records Began

IGCC began in 2023 to give annual, peer-reviewed updates of key climate indicators that allow us to check the up to date state of the climate and how human influence is changing it. The authors take the same indicators used by IPCC reports, using the same methods wherever possible. The annual updates are designed to fill the information gap for evidence-based decision making left between each IPCC Assessment cycle (around 5-10 years). This year’s study has been produced by an international team of 57 scientists, including IPCC Lead Authors, Contributing Authors, and Chapter Scientists, from 42 institutions across 15 countries.

Key findings include:

• Record high average annual GHG emissions for 2013–2022 of 53 gigatonnes of carbon dioxide.
• The global surface temperature in 2023 was 1.43°C above the 1850-1900 average in the multi-data set mean used in the study, of which 1.31°C was human induced-warming. This indicates that natural climate variability, in particular El Niño, also played a role in 2023’s record temperatures.
• Human-induced warming has risen to 1.19 °C over the past decade (2014-2023) – an increase from the 1.14 °C seen in 2013-2022 (set out in last year’s report).
• At the start of 2024, the remaining carbon budget for a 50% chance of staying below 1.5°C was estimated to be around 200bn tonnes of CO2 (GtCO2), around five years’ worth of current emissions.
• The global concentrations of carbon dioxide, methane and nitrous oxide have increased since 2019, reaching 419.3 parts per million, 1922.5 parts per billion and 336.9 parts per million, respectively, in 2023.
• Total anthropogenic effective radiative forcing has increased to 2.79 watts per square metre in 2023 relative to 1750. Sulphur emissions from shipping have fallen since the last update, meaning that their cooling effect on the climate also decreased; but this has been more than compensated for by aerosol emissions from 2023’s Canadian wildfires.
• Earth energy imbalance has increased over time, going from 0.79 watts per square metre during 2006–2018 to 0.96 watts per square metre during 2011–2023.
• Land average annual maximum temperatures, an essential indicator for climate and weather extremes, was estimated to be 1.74°C over 2014-2023.

Looking at 2023 in isolation, warming caused by human activity reached 1.3 °C. This is lower than the total amount of warming we experienced in 2023 (1.43 °C), indicating that natural climate variability, in particular El Niño, also played a role in 2023’s record temperatures.

The analysis also shows that the remaining carbon budget – how much carbon dioxide can be emitted before committing us to 1.5 °C of global warming – is only around 200 gigatonnes (billion tonnes), around five years’ worth of current emissions.

In 2020, the Intergovernmental Panel on Climate Change (IPCC) calculated the remaining carbon budget for 1.5 °C was in the 300 to 900 gigatonnes of carbon dioxide range, with a central estimate of 500. Since then, CO2 emissions and global warming have continued. At the start of 2024, the remaining carbon budget for 1.5 °C stood at 100 to 450 gigatonnes, with a central estimate of 200.

The Indicators of Global Climate Change Project is being coordinated by Professor Piers Forster, Director of the Priestley Centre for Climate Futures at the University of Leeds. He said: “Our analysis shows that the level of global warming caused by human action has continued to increase over the past year, even though climate action has slowed the rise in greenhouse gas emissions. Global temperatures are still heading in the wrong direction and faster than ever before.

“The analysis is designed to track the long-term trends caused by human activities. Observed temperatures are a product of this long-term trend modulated by shorter-term natural variations. Last year, when observed temperature records were broken, these natural factors were temporarily adding around 10% to the long-term warming.”

The warning comes as climate experts meet in Bonn to prepare the ground for the COP29 climate conference which takes place in November in Baku, Azerbaijan.

The authoritative source of scientific information on the state of the climate is the UN’s Intergovernmental Panel on Climate Change (IPCC), but as its next major assessment will not happen until around 2027, this creates an “information gap”, particularly when climate indicators are changing rapidly.

The new report is accompanied by an open data, open science platform – the Climate Change Tracker’s Indicators of Global Climate Change dashboard which provides easy access to updated information on the key climate indicators.

Earth System Science Data, also provides new insight into the effects of reductions in sulphur emissions from the global shipping industry. The sulphur has a cooling effect on the climate by directly reflecting sunlight back to space and by helping more reflective clouds to form, but ongoing reductions in those emissions have lessened that effect.

Although this was offset last year by the aerosol emissions from the Canadian wildfires, the report says the longer-term trend nonetheless indicates that the amount of cooling we can expect from aerosol emissions is continuing to decline.

“Rapidly reducing emissions of greenhouse gases towards net zero will limit the level of global warming we ultimately experience. At the same time, we need to build more resilient societies. The devastation wrought by wildfires, drought, flooding and heat waves the world saw in 2023 must not become the new normal.”

It is hoped that the report will play a strong role in informing new Nationally Determined Contributions, the improved climate plans that every country in the world has promised to put forward to the United Nations Framework Convention on Climate Change (UNFCCC) by 2025 to cut emissions and adapt to climate impacts.

The writer of this article is Dr. Seema Javed, an environmentalist & a communications professional in the field of climate and energy