Last year, global levels of atmospheric carbon dioxide reached an all-time high, rising to 150 per cent above preindustrial levels. These heat-trapping gases have triggered global temperatures to climb, testing the planet’s critical tipping points.
2025 was the third hottest year globally and marked the first three-year period where temperatures exceeded the 1.5°C threshold set out in the Paris Agreement. In Europe, heatwaves scorched the continent, fuelling deadly wildfires and subjecting citizens to a slew of heatwaves.
Analysis from Imperial College London and the London School of Hygiene & Tropical Medicine found that 68 per cent of the 24,400 estimated heat deaths last summer were due to climate change raising temperatures by up to 3.6°C.
For every 1℃ rise in air temperature, the atmosphere can also hold around seven per cent more moisture, which can lead to more intense and heavy rainfall. It’s partly why thousands were killed across Asia following overlapping monsoons last autumn.
Flash floods, which wrecked hundreds of homes and turned roads into rivers of flowing mud, also highlighted the long-term effects of deforestation.
In Indonesia, a staggering 1.4 million hectares in Aceh, North Sumatra and West Sumatra have been deforested from 2016 to 2025. These forests had previously acted as a natural flood deterrent, effectively sucking up excess water and reducing runoff volume. Without them, the country cannot cope with extreme rainfall.
Despite 2025 being plagued by extreme weather events, progress on moving away from fossil fuels was quashed at the COP30 summit in Belém. Although not on the official agenda, support for a roadmap to transition to clean energy quickly gained momentum during the talks. More than 90 countries, including the UK, Germany and the Netherlands, backed the idea of a roadmap that would allow each nation to set out its own targets to phase out fossil fuels. Brazil’s Lula da Silva was also vocal about the issue, calling on the world to “start thinking about how to live without fossil fuels”.
Yet all mentions of fossil fuels were scrubbed from the final deal in the last hours of the summit. Carbon Majors found that 17 of the top 20 emitters in 2024 were firms controlled by nations that went on to block this roadmap. This includes Saudi Arabia, Russia, China, India, Iraq, Iran and Qatar.
“The national and international responses to the climate emergency went from wholly insufficient to profoundly destructive,” the Bulletin says.
“None of the three most recent UN climate summits emphasised phasing out fossil fuels or monitoring carbon dioxide emissions. In the United States, the Trump administration has essentially declared war on renewable energy and sensible climate policies, relentlessly gutting national efforts to combat climate change.”
