What's the latest climate science as COP30 gathers?

Climate change is accelerating, and extreme weather events and other impacts have a growing impact on the environment and populations around the world. Here are some of this year's developments in climate science.

WARMER AND FASTER The global temperatures are climbing not only faster, but also warmer than ever before. New records have been set for 2023, 2024 and even at some points in 2025. This finding was made in a June study that updated the baseline data for the Intergovernmental Panel on Climate Change's science reports. New research indicates that the average global temperature is rising by 0.27 degrees Celsius per decade, or 50% faster than it did in the 1990s & 2000s.

The sea level is also rising faster - by about 4.5 millimeters a year in the past decade, as opposed to 1.85 mm a year since 1900. Scientists warn that the world will reach a threshold of 1.5 C by 2030. After this, we may trigger irreversible, catastrophic impacts. According to the World Meteorological Organization, the Earth has already warmed up by 1.3-1.4 C compared to pre-industrial times.

TIPPING POINTS The death of warm-water corals is almost irreversible due to successive marine heatwaves. This would mark the first "climate tipping point", when an environment system starts to shift from one state into another. Researchers warned in October that the Amazon rainforest would begin to shrink and change into a savannah if deforestation continued at a rapid rate as global temperatures reached 1.5 C. This is much earlier than originally estimated.

Scientists said melting water from Greenland's thawing glacier could cause an earlier collapse of the Atlantic Meridional Overturning Circulation (AMOC), which keeps Europe's winters mild. Scientists are concerned about the declining sea ice around Antarctica where ice sheets also threaten. As in the Arctic region, the loss of ice exposes dark waters that absorb more solar radiation. This amplifies global warming. This also threatens the growth and consumption of CO2 by phytoplankton.

Land on Fire

Wildfires are still likely to be severe and frequent, along with heatwaves. The State of Wildfires Report, led by a coalition of universities and weather agencies, estimated that 3.7 million square kilometers (1,4 million square miles), or an area the size of India combined, had burned between March 20,24 and February 20,25.

The average annual fires for the past two decades was about a third less. The fires did produce higher CO2 than previously, because more dense forests were burned.

Researchers are trying to determine the health effects of heat, and how to reduce them. The U.N. weather and health agencies say that about half the population of the world is already suffering from it. They also estimate that worker productivity drops 2-3% per degree above 20 C. A study published in the Lancet journal last October estimated global losses of over $1 trillion due to this lost productivity.

The definition of a heat-related fatality is not consistent internationally, but technological advances help scientists bridge data gaps to compare conditions across the globe. In Europe, for example, a team from the UK's Imperial College estimated that more than 24,400 deaths were caused by heat exposure this summer among about 30% of European population. Based on mortality trends, they attributed as much as 70% of these deaths to climate-driven heat. Another team examined mortality data, temperature data, and health parameters to estimate the number of heat-related deaths in Europe during last summer's record-breaking hot weather. This included more than 62 700 deaths, which is about 70%, across 32 countries.

SCIENCE UNDER ASSESSMENT The U.S. Administration under climate-denying president Donald Trump hopes to cut funding for agencies that monitor and collect climate and weather data. This is alarming a scientific community who say that U.S. Leadership will be difficult to replace. Trump's budget request for 2026, which has yet to be approved in Congress, proposes cutting NOAA spending by over a quarter, to $4.5 billion, and halving NASA Earth Science's budget to around $1 billion. It also eliminates its climate research division. In other countries, science budgets are increasing. China, Japan, the UK and the European Union have all set records for their science research. Last month, the EU opened up its real-time monitoring of weather data to the public. Reporting by Ali Withers and Kat Daigle from Copenhagen; editing by Ni Williams

(source: Reuters)