Planet’s vital signs deteriorate at unprecedented pace since last UN climate assessment, warns new paper released at Bonn Climate Conference 2026

Major indicators of global climate change like daily temperatures have worsened since the last United Nations climate science assessment, with marine heatwaves showing the sharpest rise, according to a new global study presented at the ongoing 64th Sessions of the UNFCCC Subsidiary Bodies (SB64), also known as the Bonn Climate Change Conference.

The study, published in the international interdisciplinary journal Earth System Science Data, was carried out by about 70 scientists from 17 countries, including India, and led by the University of Leeds. Several authors of past UN climate science reports were involved in the work.

The study is intended to fill the information gap between assessment reports of the Intergovernmental Panel on Climate Change (IPCC), the UN-backed scientific body that assesses climate science.

The IPCC’s sixth assessment report was published in stages between 2021 and 2023. The new study uses similar methods to track how key climate indicators have changed since then.

“The (current) study aims to fill potential information gaps between IPCC reports, providing decision makers with timely and scientific information on policy-relevant global climate indicators such as levels of greenhouse gas emissions, human-caused warming, and temperature and climate extremes,” the report said.

Indicators move in wrong direction

The study found that all 11 climate indicators it assessed had increased since the IPCC’s last assessment cycle. Marine heatwaves showed the highest rise, increasing by 61.1 per cent. Earth’s energy imbalance rose by 41.8 per cent, while maximum daily temperature increased by 23.9 per cent. Human-induced warming rose by 15.9 per cent, the study said.

Overall greenhouse gas levels increased by 2.1 per cent. Carbon dioxide and methane rose by 3.8 per cent each, while nitrous oxide increased by 2.2 per cent. Human activities pushed global warming to 1.37 degrees Celsius (°C) in 2025, which the report identifies as the third-warmest year on record.

The study projects that the 1.5°C warming threshold could be exceeded in about four years if current trends continue. Relative to pre-industrial levels, land temperatures increased by 1.81°C over the 2016-2025 decade, while ocean temperatures rose by 1.03°C.

The pre-industrial period, generally taken as 1850-1900, is used as the baseline for measuring human-caused global warming.

One climate expert at the Bonn talks, who did not wish to be named, said the findings showed a widening gap between climate science and political action. “All the data are showing that the global climate is moving in the wrong direction,” the expert said. “Politicians must take responsibility for this suicidal trend.”

Heat accumulating faster

Professor Piers Forster, director of the Priestley Centre for Climate Futures at the University of Leeds and lead author of the report, said Earth’s energy imbalance is now at a record high. Earth’s energy imbalance measures how quickly heat is accumulating in the climate system. Without human influence, it should be close to zero, Forster said.

Instead, it has been growing since the 1970s and has doubled in recent decades. The report found that global greenhouse gas emissions have reached an all-time high of 56.8 billion tonnes of carbon dioxide equivalent, mainly from burning fossil fuels.

“Our study demonstrates that nearly all of the warming over the last decade is driven by human activities,” said Samantha Burgess, a weather expert at the European Centre for Medium-Range Weather Forecasts and one of the study’s authors.

“The impacts on livelihoods and ecosystems are already being felt worldwide, and will accelerate as temperatures continue to increase,” she said. The rate of human-induced warming remains at an all-time high of about 0.27°C per decade, the study said.

This is driven mainly by record greenhouse gas levels, along with falling sulphur dioxide emissions. While reducing sulphur dioxide helps cut air pollution, it also reduces the cooling effect of sulphur aerosols, partly revealing more of the warming caused by greenhouse gases.

India and the Indian Ocean

India is among the countries highly exposed to rising heat. Surface air temperatures have increased significantly over the past century, contributing to more severe and prolonged heatwaves. In 2026, heatwaves began earlier than usual in parts of the country.

Marine heatwaves are also increasing, with potential consequences for fisheries, monsoon behaviour, coastal ecosystems and cyclones. “Our research shows that the Indian Ocean is moving towards a near-permanent marine heatwave state by the 2050s,” said Roxi Mathew Koll, a scientist at the Indian Institute of Tropical Meteorology.

A 2024 study by Koll found that the tropical Indian Ocean has warmed across the basin since the start of the 20th Century. Between 1950 and 2020, it warmed at 0.12°C per decade, the fastest rate among tropical ocean basins.

The warming has also penetrated into the deep ocean, with ocean heat content rising down to 2,000 metres.

Climate models project that, under medium to high greenhouse gas emissions, the Indian Ocean could warm by 1.4°C to 3°C between 2020 and 2100. The same study projected that marine heatwaves in the tropical Indian Ocean could increase from about 20 days a year during 1970-2000 to 220-250 days a year by the end of the century.

That would push the region towards a basin-wide near-permanent marine heatwave state, with serious implications for India and other countries around the Indian Ocean.