Arctic sea ice reached its smallest extent of the year on September 12, NASA and the National Snow and Ice Data Center reported. The ice covered about 4.6 million square kilometres, or 1.78 million square miles, tying with 2008, 2010 and 2025 for the tenth-lowest minimum since satellite records began in 1978. The past 20 years have produced the 20 lowest minimums in the record. At the other pole, Antarctic sea ice probably reached its yearly maximum on September 14 at 17.59 million square kilometres, which would be the third-lowest Antarctic maximum on record.
NOAA's Climate Prediction Center says there is a greater than 90% chance of a very strong El Nino during the 2026-27 autumn and winter. Sea surface temperatures in the eastern equatorial Pacific are more than 3C above average, and European seasonal models project the event could peak at levels never recorded since 1950. NOAA's winter outlook favours warmer-than-normal conditions across the northern United States and a wetter pattern in the south. Climate Week NYC is meeting in New York as governments weigh the risks. Forecasters will update the outlook in October, when the peak strength of the event should be clearer.
Heat waves over land are starting earlier, ending later and lasting longer, according to a study published in Nature Climate Change on 23 September. Across a 45-year record, the first heat wave of the season arrived about two weeks earlier and the last one came about 24 days later, lengthening the season by roughly 39 days. The season is now expanding by 8.71 days per decade, and recent years show a new shift: the first heat wave builds faster than it used to. Drylands are seeing the biggest timing changes.
Nepal's prime minister, Balendra Shah, is expected to press for climate compensation when he addresses the UN General Assembly on 24 September. The appeal follows the 26 August disaster in Langtang National Park, where a partial glacier collapse sent a debris flow nearly 100 km down the Lende Khola and Trishuli rivers. More than 1,000 people are confirmed dead, hundreds are still missing, and hydropower stations were destroyed. Nepal's glaciers have lost close to a third of their ice volume in about three decades. The country is seeking money from the Fund for Responding to Loss and Damage.
Forecasters expect a historic super El Nino to peak between November 2026 and January 2027, and aid agencies are already planning for the consequences. The International Rescue Committee warns the pattern could quickly worsen food security across Honduras, Guatemala and El Salvador, where subsistence farmers depend on a short rainy season. Conflict-disrupted shipping has also pushed up the cost of imported food, fuel and fertiliser, leaving households with less room to absorb a failed harvest. Meanwhile Indonesia is fighting its most intense fire season in 11 years, with Malaysia sending assistance, and China put August disaster losses at 36.03 billion yuan, about $5.38 billion.
Indonesia is battling its worst wildfire season in 11 years, with fires across Borneo and Sumatra spreading haze over parts of the region. President Prabowo Subianto has called for stricter regulations and sanctions against people and companies behind deliberate slash-and-burn land clearing, describing the practice as ecological terrorism and demanding zero tolerance. Much of the burning is in peatland, where fires smoulder underground and can reignite weeks later, making them costly to fight and hard to measure by satellite. Officials point to a dry El Nino pattern, while researchers say enforcement during this season will show whether the tougher rules have any effect.
A United Nations Environment Programme report called Limiting Overshoot says there are no plausible scientific pathways that keep global warming below 1.5 degrees Celsius, and that the limit will be breached within the next few years. In the most optimistic scenario, peak warming reaches about 1.8 degrees. UNEP chief Inger Andersen said every fraction of a degree will cost lives, and the report warns that even a temporary exceedance will leave irreversible losses. The findings arrive as Climate Week NYC runs from September 20 to 27, with governments, investors and companies meeting in New York to discuss emissions cuts and adaptation funding.
The Environmental Protection Agency has repealed most of the 2024 rules limiting greenhouse gas emissions from coal and gas fired power plants, and proposed scrapping the remaining federal limits on the sector. Administrator Lee Zeldin signed the final rule on 14 September. EPA said the repealed provisions relied on technology that is not available at the needed scale and speed, and estimates the change removes more than $300 billion in costs for plant operators. A companion proposal would rescind the findings that underpin regulation of power plant greenhouse gases, with a public hearing set for 1 October.
Indonesia's Forestry Minister Raja Juli Antoni told local media that wildfires could continue until early November, because the rainy season is expected to arrive late. He urged people to stop using fire to clear land during the extended drought. Many Indonesian fires burn on peatland, where dried organic matter can smoulder underground for weeks, releasing large volumes of carbon dioxide and fine particulate matter whose smoke can cross borders. Studies have estimated that the country's 2015 peat fires released more carbon in a few months than the annual emissions of many industrialised nations.
Residents and environmental groups in San Jose are organizing against a wave of proposed data center projects that city officials have courted to position the area as a hub for AI infrastructure. About 20 data centers already operate in the city, and more than 100 dot Silicon Valley. City officials estimate each new facility could generate $3 million to $6 million a year in tax revenue for police, fire, libraries, roads and parks. Opponents say too little is known about power and water use and whether the benefits will be shared. The Data Center Coalition, whose members include Google, Meta, OpenAI and Anthropic, warns that bills targeting data centers could push investment to other states.