Rate of Human-Caused Global Warming is at an All-time High, Scientists Explain

The second annual Global Climate Change Indicators report, led by the University of Leeds, reveals that human-induced warming has increased to 1.19°C over the past decade (2014-2023), an increase from previous 1.14°C observed in 2013-2022 (established in last year's report)

Image for illustration only. Credit: CC0 Public domain

Considering the year 2023 in isolation, the warming caused by human activity reached 1.3 °C. This is less than the total amount of warming we experienced in 2023 (1.43°C), indicating that natural climate variability, particularly El Niño, also influenced 2023's record temperatures.

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

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

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

"Our analysis is designed to track long-term trends caused by human activities. The observed temperatures are a product of this long-term trend modulated by short-term natural variations. Last year, when observed temperature records were broken, "These natural factors were temporarily adding about 10% to the long-term warming."

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

The authoritative source of scientific information on the state of the climate is the United Nations' Intergovernmental Panel on Climate Change (IPCC), but with its next major assessment not due until around 2027, this creates an "information gap", particularly when climate indicators are changing rapidly.

The new report is accompanied by an open data and open science platform: the Climate Change Tracker Global Climate Change Indicators Dashboard, which provides easy access to up-to-date information on key climate indicators.

The Earth System Science Data report

The latest Indicator report, published by more than 50 scientists in the journal Earth System Science Data, also provides new insights into the effects of reductions in sulphur emissions from the global shipping industry. Sulphur has a cooling effect on the climate by directly reflecting sunlight into space and helping more reflective clouds form, but ongoing reductions in those emissions have diminished that effect.

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

Key indicators of climate change in 2023. Earth System Science

Other key findings

- Human-induced warming has increased to 1.19°C over the past decade (2014-2023), up from 1.14°C observed in 2013-2022 (set out in last year's report) .

- Human-induced warming has been increasing at a rate unprecedented in the instrumental record, reaching approximately 0.26 °C per decade during the period 2014-2023.

- This high rate of warming is caused by a combination of greenhouse gas emissions, GHGs, which are consistently high, equivalent to 53 billion tons of CO2 per year, as well as continued improvements in air quality, which are reducing the force of man-made cooling caused by particles. in the atmosphere.

- High levels of GHG emissions are also affecting the Earth's energy balance: ocean buoys and satellites are tracking unprecedented heat flows into the Earth's oceans, polar caps, soils and atmosphere. This heat flux is 50% greater than its long-term average.

Professor Forster added: "Fossil fuel emissions account for around 70% of all GHG emissions and are clearly the main driver of climate change, but other sources of pollution such as cement production, agriculture and deforestation and Cuts in the level of sulphur emissions are also contributing to warming."

"Rapidly reducing greenhouse gas emissions towards net zero emissions will limit the level of global warming we will ultimately experience. At the same time, we need to build more resilient societies. The devastation caused by wildfires, droughts, floods and waves of heat that the world saw in 2023 must not become the new normal.

The report is expected to play an important role in informing the new Nationally Determined Contributions, the enhanced climate plans that every country in the world has promised to submit to the United Nations Framework Convention on Climate Change (UNFCCC). by 2025 to reduce emissions. and adapt to climate impacts.

Reference:

Indicators of Global Change report, Earth System Science Data (2024).