Record-breaking climate trends continued in 2024 and 2025. Globally averaged temperature in 2024 was at the warmest level in 175 years of record-keeping. Likewise, atmospheric carbon dioxide—the greenhouse gas most responsible for human-caused climate change—reached a new high of 152 percent of 1750 levels. The oceans continue to absorb about 90 percent of the heat added by climate change, and globally averaged sea surface temperatures are the warmest in the modern satellite and buoy record. The Conejeres Glacier in Colombia was declared extinct, and all glaciers in Venezuela have joined a long list of glaciers that are endangered or have disappeared. With the addition of freshwater from melting glaciers and thermal expansion, global averaged sea level rise reached the highest level in the satellite record of sea level, which began in 1993.

The hydrologic cycle, energized by the warm temperatures, became erratic, with deluges and droughts hopscotching around the globe. Large swaths of Peru, the Amazon, southern Africa, and northwest Africa experienced droughts, while the state of Rio Grande do Sul in southeast Brazil received record rainfall, and extensive floods occurred in Congo River Basin. Parts of Asia and Central Europe were also wetter than normal while Canada experienced both its hottest and driest year on record. “An estimated 3.6 billion people face inadequate access to water at least one month per year and this is expected to increase to more than 5 billion by 2050,” according to the UN, and the world is falling far short of the UN Sustainable Development Goal set for water and sanitation.

There were over 60,000 heat-related deaths in the summer heatwave in Europe. Floods in the Congo displaced 350,000 people. The deluge at Rio Grande do Sul displaced over half a million people. In the United States, the number of severe climate disasters increased nearly five-fold in 2024, compared to the 1990-2000 decade. Furthermore, the average time between these severe disasters is just 12 days, compared to an average of 82 days in the early 1980s.

Total carbon dioxide emissions—the sum of fossil fuel and land-use change emissions—continued to increase in the decade 2014-2023, albeit more slowly than in the preceding decade. The global average concentration of carbon dioxide in 2024 was 3.5 parts per million higher than in 2023, which is the largest annual increase since modern measurements started in 1957. There also is concern that terrestrial and ocean carbon dioxide sinks that absorb approximately half the fossil and land-use carbon dioxide are becoming less effective. Combustion of coal continues to dominate carbon dioxide emissions, though coal use has plateaued in the most recent decade. Notably, though, China's fossil carbon dioxide greenhouse gas emissions, which accounted for 32 percent of global emissions in 2024, have plateaued and seem likely to fall in the future, given that country’s strides in renewable energy.

Renewable energy, especially wind and solar, saw record growth in both capacity and generation in 2024. Renewable capacity approached 4,500 gigawatts, and in 2024, renewable and nuclear energy together surpassed 40 percent of global electricity generation for the first time. Furthermore, renewables overtook coal’s share in the global electricity mix in the first half of 2025.

The goal of the 2025 UN climate summit in Belém, Brazil (COP30) was accelerating climate action and a “just transition” that would support workers and communities moving away from fossil fuels. For the first time in a decision issued in such a forum, though, the Belém text acknowledged the possibility that the world would overshoot the goal of limiting global warming to 1.5 degrees Celsius above preindustrial levels, saying “both the extent and duration of an overshoot need to be limited.” The summit also failed to firmly endorse the Intergovernmental Panel on Climate Change (IPCC) as the “best available science” on climate. None of the last three UN climate summits has emphasized phasing out fossil fuels or monitoring emissions.

The UN Environment Programme’s “The Emissions Gap Report 2025: Off Target” concludes that full implementation of the targets for national reductions in greenhouse gas emissions put forward at the 2015 climate summit in Paris will allow global temperature to rise by 2.3 to 2.5 degrees Celsius this century, and targets based on current policies will raise temperature by 2.8 degrees. The report further finds that deployment of mitigation strategies remains inadequate, and reliance on carbon dioxide removal to help combat climate change is an uncertain, risky, and costly proposition.

In the United States, the Trump administration’s agenda—which seeks to systematically repeal targets and policies, as well as decimate funding for climate change mitigation and science, among other things—is the most aggressive, comprehensive, and consequential climate policy rollback that the authoritative Climate Action Tracker has ever analyzed. The administration has proposed and/or implemented across-the-board halting of carbon dioxide, climate, and environmental data collection and has also threatened to shutter or break up the major climate modeling centers that produce projections critical for developing optimal strategies for climate adaptation and mitigation. The cessation of data collection includes, but is not limited to, the National Oceanic and Atmospheric Administration’s iconic carbon dioxide monitoring at the Mauna Loa Observatory in Hawaii; NASA’s OCO-2 and OCO-3 satellites, which monitor carbon dioxide from space; and the Environmental Protection Agency’s Greenhouse Gas Reporting Program to track industrial and agricultural emissions. The data and information gaps created by the administration’s actions, although partially filled by other countries and/or the private sector, will mean that there is limited cross-check on greenhouse gas emitters and hindered projections of future climate. Emission reduction and climate mitigation efforts may now be flying blind.

Reducing the threat of climate catastrophe requires actions both to reduce the cause and to deal with the damage of climate change. First and foremost, come reductions in emissions of greenhouse gases from the burning of fossil fuels to produce energy. Technologies for renewable energy are now mature and cost effective. Governments should ramp up their efforts to widely deploy these clean energy technologies by providing incentives to produce them on a large scale and to create markets for them. Equally important in the fight against climate change is renewed reliance on science that tracks and guides emission reduction and mitigation efforts. This return to science-based climate policy includes the collection, validation, and sharing of climate and greenhouse gas information around the world, as well as the enhancement of model projections of climate impacts on the wellbeing of all inhabitants of the planet.

Read the 2026 Doomsday Clock statement »