It’s intuitive to think that if a tree is photosynthesizing, it’s also growing. But that’s not necessarily so—and a new study of oak trees, published in the journal Science Advances, found that even as they photosynthesize late into the year, their growth stops by mid-summer. Much of the long-term carbon storage that forests provide depends on trees converting the carbon they absorb through photosynthesis into new wood. Many researchers have predicted that rising atmospheric carbon dioxide (CO2) levels will enhance photosynthesis and stimulate tree growth, putting some of that planet-warming carbon into long-term storage inside wood. However, the observed decoupling of photosynthesis from growth suggests that increased carbon uptake does not necessarily translate into greater wood production. Instead, some of the absorbed carbon may be used to produce foliage or used in short-lived metabolic processes rather than being locked away long term, reducing the amount of carbon stored in forests compared with previous expectations.

A new paper by leading climate scientists and policy experts finds that indirect greenhouse gases account for roughly 15% of current global warming from human emissions yet remain largely absent from climate policy. These overlooked pollutants, including carbon monoxide, non-methane volatile organic compounds, nitrogen oxides, and molecular hydrogen, do not warm the climate directly. Instead, they alter atmospheric chemistry in ways that increase levels of methane, ozone, and other greenhouse gases, which results in increased warming. Reducing these emissions represents an overlooked opportunity to slow warming while delivering air quality benefits.

Most people have experienced a heat wave on land. But heat waves can strike in the ocean too. Researchers say a controversial strategy to shield Earth from some of the sun’s rays would offer unequal protection for the oceans and communities that depend on them, leaving 25% to 75% of the world’s seas still at risk from overheating.

Climate change will profoundly alter the dynamics of sea and land breezes in the Barcelona metropolitan area, trapping larger amounts of air pollutants over coastal areas and increasing health risks for millions of people. This is the conclusion of a study conducted by the Institute of Environmental Science and Technology of the Universitat Autònoma de Barcelona (ICTA-UAB), Spain, which produced high-resolution projections of future sea and land breeze behaviour and air quality under climate change scenarios for 2050 and 2100.

Strong and consistent evidence shows that the entire climate system is continuing to heat, driving rapid global warming. Human activities pushed global warming to 1.37°C in 2025, and its level is projected to surpass 1.5°C in about four years. Crucially, the rate at which heat is accumulating in the Earth system suggests high levels of future warming. These are some of the key findings from the latest Indicators of Global Climate Change (IGCC) report, published today in Earth System Science Data.

An international team of more than 70 scientists, including IPCC Lead Authors, Contributing Authors, and Chapter Scientists, from 56 institutions across 17 countries contributed to this year’s IGCC study.

Breakbone fever. The nickname alone attests to the pain that dengue fever can cause. About half the people who get the virus are asymptomatic. But for the rest, an infection can be excruciating, even life-threatening, and there is no treatment.