Study shows 2024 was the hottest in at least the previous 125,000 years

Last year was the hottest year ever recorded, and likely the hottest in at least 125,000 years. An international team of scientists warns that the world is sliding toward what they call “climate-driven chaos.”

Their assessment found that 22 of 34 planetary climate “vital signs” are now at record levels. To avoid it, governments, businesses, and citizens must act far more quickly to cut emissions and restore nature.

“Without effective strategies, we will rapidly encounter escalating risks that threaten to overwhelm systems of peace, governance, and public and ecosystem health,” said co-lead author William Ripple from Oregon State University.

“In short, we’ll be on the fast track to climate-driven chaos, a dangerous trajectory for humanity.” Still, the authors insist it is not too late to blunt the worst impacts – if action is swift.

Record heat, record climate warnings

The report draws on the latest Intergovernmental Panel on Climate Change (IPCC) datasets and ends up with a stark summary: greenhouse gas concentrations, ocean heat, ocean acidity, and ice loss continue to rise.

Fossil fuel energy consumption in 2024 hit a record high. Solar and wind also hit records, but together they were still 31 times lower than fossil fuels.

Warming itself seems to be accelerating, likely because we’re losing cooling from atmospheric aerosols, getting stronger heat-enhancing cloud feedbacks, and reducing Earth’s albedo.

That extra climate heat showed up in other systems too: ocean heat content is the highest ever measured, and wildfire-related tree cover loss is the highest on record.

Moreover, by August 2025, the European Union had already logged its most extensive fire season, with more than 1 million hectares (2.47 million acres) burned.

Deadly weather also surged: Texas flooding killed at least 135 people; Los Angeles wildfires caused more than $250 billion in damages; and Typhoon Yagi killed more than 800 people in Southeast Asia.

Meanwhile, the Atlantic Meridional Overturning Circulation (AMOC) is weakening, raising the risk of major shifts in rainfall and temperature across the Atlantic basin.

Living beyond Earth’s means

“The human enterprise is in a state of ecological overshoot where the Earth’s resources are being consumed faster than they can be replenished,” said co-lead author Dr. Christopher Wolf from Terrestrial Ecosystems Research Associates.

“Population, livestock, meat consumption, and gross domestic product are all at record highs, with an additional 1.3 million humans and half a million ruminant livestock animals added every week.”

That growth is pushing us past nature’s recharge rate. The report argues that tackling overshoot means more than decarbonizing.

It means reducing overconsumption by the wealthiest, rewiring food systems, and protecting ecosystems that are still absorbing carbon and buffering heat.

Three keys to climate recovery

The authors focus on three areas that can still deliver big wins fast. The first is energy. Renewables such as solar and wind could provide up to 70 percent of global electricity by 2050.

A rapid, socially just phaseout of fossil fuels would make the single largest contribution to mitigation.

“We also need grassroots movements advocating for a socially just phaseout of fossil fuels and limits on the fossil fuel industry’s financial and political influence,” Ripple said.

The second is ecosystems. Protecting and restoring forests, mangroves, peatlands and wetlands could remove or avoid around 10 gigatons of CO2 per year by 2050 – about a quarter of today’s annual emissions – while supporting biodiversity and water security.

Third is food systems. Cutting food loss and waste – now 8 to 10 percent of global emissions – and shifting diets toward more plant-rich foods would cut emissions, improve health, and ease pressure on land and water.

Security faces a warming world

“What’s urgently needed are effective climate mitigation and adaptation strategies, including ones that embed climate resilience into national defense and foreign policy frameworks,” Ripple said.

That means planning for record climate shocks, migration, and supply chain disruptions as core security issues, not side projects.

The report also highlights the power of social tipping points. Sustained, nonviolent movements have shifted public norms before – on civil rights, public health, the ozone layer.

Similar movements can push governments to end fossil fuel subsidies, protect forests, and regulate the industries that profit from delay.

Degrees decide our climate future

A core message runs through the report: small temperature differences have big consequences. Each tenth of a degree that we avoid reduces the odds of extreme heat, megafires, crop failures, and water crisis.

Delaying action locks in higher costs and deadlier outcomes; fast, coordinated measures bring immediate benefits.

“Climate mitigation strategies are available, cost effective and urgently needed, and we can still limit warming if we act boldly and quickly, but the window is closing,” Ripple said.

“The cost of mitigating climate change is likely much, much smaller than the global economic damages that climate-related impacts could cause.”

2024 showed what a hotter, more combustible planet looks like. 2025 is confirming the trend. But the report doesn’t just argue for despair.

It advocates speed, fairness, and using the tools we already have – clean energy, nature protection, smarter food systems, and people power – before this “planet on the brink” tips further toward the chaos the scientists are warning about.

The full report is published in the journal BioScience.

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