As the end of 2025 approaches, regular folk take stock of the past year, and maybe ponder their New Year’s resolutions. Climate scientists, on the other hand, have been busy parsing mountains of data from the last 10 months, ranging from global temperatures to measurements of polar ice to the costs of extreme weather. Accordingly, their goal for 2026 might be to somehow make world leaders understand that humanity is running out of time to avert catastrophe.

A recent superflood in Valencia, Spain, proved one of the greatest disasters in modern history.

Language from scientists doesn’t get much more alarming than that — and they’ve got good reason to be frightened. In 2023, for instance, the ability of the land to absorb our carbon emissions dropped significantly. The report confirms that last year was the hottest on record, and was likely the hottest in at least 125,000 years. This year, Greenland’s and Antarctica’s ice mass hit record lows, and extreme heat in the oceans drove the largest coral bleaching event on record, with over 80 percent of the world’s reef area affected. Accordingly, earlier this month another team of researchers announced that the world has reached its first major tipping point — in which an Earth system dramatically changes, often irreversibly — as many coral ecosystems pass a point of no return. And in September, still more scientists declared that we’ve hit the seventh of nine planetary boundaries — thresholds that keep our world hospitable to life — as ocean acidification continues to worsen. Taken together, the developments show that humanity is pushing critical Earth systems toward collapse. 

Which is not to say that there’s nothing we can do to stop the runaway deterioration of Earth’s systems. The prices of renewable energy and batteries, for instance, have fallen so precipitously that it’s even taken experts by surprise, meaning ditching fossil fuels makes excellent economic sense. We just need politicians to get serious about decarbonization: Next month at the COP30 climate conference in Brazil, nations will have to redouble their efforts to reduce emissions. “It’s really serious, but it’s not game over,” said R. Max Holmes, president and CEO of the Woodwell Climate Research Center, which wasn’t involved in the report. “There’s still hope. There’s still stuff that we can do, and that’s what we need to lean into.”

Still, the report makes it clear that the severe consequences of climate change, which scientists have long warned about, are here. “The main message is that the planet’s vital signs are flashing red,” said William J. Ripple, a professor at Oregon State University and co-lead author of the report, in an email to Grist. “Twenty-two of 34 tracked indicators are now at record extremes, from ocean heat content to global wildfire extent and Antarctic ice loss. We’re witnessing accelerating warming and a worsening of almost every key Earth system trend.”

Driving this is humanity’s failure to dramatically reduce its greenhouse gas emissions. In fact, energy-related emissions rose 1.3 percent last year, the report notes. That’s due primarily to a lack of ambition from governments to switch to renewables, but may also reflect a feedback loop: The hotter it gets, the more people need to run energy-hungry air conditioners to stay healthy, which results in more emissions and more AC use. 

At the same time, Earth’s systems are struggling to save us from ourselves. Normally, oceans and forests absorb CO2, as marine phytoplankton and terrestrial plants sequester the gas as they grow. But scientists have found a significant loss of phytoplankton in many parts of the sea in recent decades. And in 2024, the planet lost the second highest amount of forest on record. That’s due to deforestation and ever-fiercer wildfires that obliterate ecosystems — warmer temperatures and worsening droughts prime vegetation to burn catastrophically — instead of smaller, less intense blazes naturally resetting them for new growth. 

All told, loss of primary forest last year produced the equivalent of 8 percent of humanity’s emissions. And 2025 hasn’t brought any relief. Canada is suffering through a historic wildfire season, with the second largest area burned on record. That’s been consistently pouring smoke — likely infused with toxic metals from mining operations — across the country and into the United States, leading to extremely unhealthy air quality. 

This smoke initiates another feedback loop, as more carbon spews into the atmosphere, which causes more warming, which in turn worsens wildfires and produces more carbon. Those extra emissions could be helping push other systems to points of no return, further accelerating warming. That, in turn, could set the stage for a “hothouse Earth” scenario, in which the planet keeps warming even if emissions fall. “We’re edging closer to a chain reaction of feedback loops and tipping points including melting ice sheets, thawing permafrost, and forest dieback that could push Earth into a self-sustaining warming path,” said Ripple, who is also the director of the Alliance of World Scientists, which focuses on the climate crisis. “The risk now is that even if emissions fall later, the climate system may keep heating on its own. We might be dangerously close to triggering climate feedbacks that humanity can’t simply switch off.”

Indeed, the report notes that global warming may be speeding up. That could be partly due to an environmental victory, ironically enough: Air quality regulations have been reducing the emission of aerosols, which improves public health. But those aerosols normally reflect some of the sun’s energy back into space — and help brighten clouds to bounce still more energy — so losing them leads to more heating. “We’re seeing the planet heat up faster than expected,” Ripple said. “Surface temperatures are increasing more steeply than past trends would suggest.”

The cascading effects of this warming are getting worse by the year, because each bit of warming, disasters grow deadlier and more expensive. The hotter the ocean gets, for instance, the more fuel for monster tropical cyclones: Last year, Hurricane Helene killed 251 people and caused $79 billion in damages, and early indications are that Hurricane Melissa caused catastrophic destruction as it rolled across Jamaica on Tuesday. In January, the Los Angeles wildfires caused at least $250 billion in damages. And according to one group of researchers, the fires didn’t kill 30 people, as the official tally states, but more like 440 when you factor in those who may have died from the effects of smoke. Separately, last month researchers calculated that wildfire smoke already kills 40,000 Americans each year, which could jump to 71,000 by 2050 if greenhouse emissions remain high. 

All of these findings point to one conclusion: Without a drastic course correction, we’re on track to reach as much as 3.1 degrees Celsius above preindustrial levels — miles above the Paris Agreement’s goal of keeping it below 2 degrees, and even more ideally, 1.5 degrees — by 2100. The costs of climate change will be astronomically greater than preventing that warming by investing in renewables, fighting overconsumption, and protecting the ecosystems that naturally sequester carbon. “Our message is clear,” Ripple said. “We need to act boldly and act now. Every fraction of a degree matters. Delays only magnify suffering and costs.”