Earth's climate imbalance

The World Meteorological Organization’s (WMO) State of the Global Climate report 2025 confirms that 2015-2025 are the hottest 11 years on record, and that 2025 was the second or third hottest year on record, at about 1.43C above the 1850-1900 average.

Extreme events around the world, including intense heat, heavy rainfall and tropical cyclones, caused disruption and devastation and highlighted the vulnerability of our inter-connected economies and societies.

The ocean continues to warm and absorb carbon dioxide. It has been absorbing the equivalent of about eighteen times the annual human energy use each year for the past two decades. Annual sea ice extent in the Arctic was at or near a record low, Antarctic sea ice extent was the third lowest on record, and glacier melt continued unabated, according to the report.

“The state of the global climate is in a state of emergency.  Planet Earth is being pushed beyond its limits.  Every key climate indicator is flashing red,” said UN Secretary-General António Guterres.

“Humanity has just endured the eleven hottest years on record. When history repeats itself eleven times, it is no longer a coincidence.  It is a call to act,” said Mr Guterres.

 WMO’s flagship State of the Global Climate report was released on World Meteorological Day on 23 March, which has the theme Observing Today, Protecting Tomorrow.

For the first time, the report includes the Earth’s energy imbalance as one of the key climate indicators.

The Earth’s energy balance measures the rate at which energy enters and leaves the Earth system. Under a stable climate, incoming energy from the sun is about the same as the amount of outgoing energy. 

However, increasing concentrations of heat-trapping greenhouse gases - carbon dioxide, methane and nitrous oxide - to their highest level in at least 800,000 years have upset this equilibrium.

The Earth’s energy imbalance has increased since its observational record began in 1960, particularly in the past 20 years. It reached a new high in 2025. 

 “Scientific advances have improved our understanding of the Earth’s energy imbalance and of the reality facing our planet and our climate right now,” said WMO Secretary-General Celeste Saulo. “Human activities are increasingly disrupting the natural equilibrium and we will live with these consequences for hundreds and thousands of years.”

“On a day-to-day basis, our weather has become more extreme. In 2025, heatwaves, wildfires, drought, tropical cyclones, storms and flooding caused thousands of deaths, impacted millions of people and caused billions in economic losses,” said Celeste Saulo.

The warming of the atmosphere including near the Earth’s surface (the temperatures that humans feel) represents just one percent of the excess energy, whilst about five percent is stored in the continental land masses.

More than 91 percent of the excess heat is stored in the ocean, which acts as a major buffer against higher temperatures on land. Ocean heat content reached a new record high in 2025 and its rate of warming more than doubled from 1960-2005 to 2005-2025.

Another three percent of the excess energy warms and melts ice. The ice sheets on Antarctica and Greenland have both lost significant mass and the annual average Arctic sea-ice extent for 2025 was the lowest or second lowest on record in the satellite era. Exceptional glacier mass loss occurred in Iceland and along the Pacific coast of North America in 2025. 

 he warming ocean and melting ice are driving the long-term rise in global mean sea level, which has accelerated since satellite measurements began in 1993.

Ocean warming and sea level rise will continue for centuries, according to projections by the Intergovernmental Panel on Climate Change (IPCC). Changes in ocean warming, and deep ocean pH are irreversible on centennial to millennial time scales.

The report is accompanied by an interactive story map. It has a dedicated supplement on extreme events, highlighting their cascading impacts, including on food insecurity and displacement.

It includes a chapter on climate and health, showing how rising temperatures, shifting rainfall patterns and changes in extremes are affecting where and when health risks emerge, how severe they become and who is most exposed.

It highlights the examples of the mosquito-borne dengue disease and of heat stress – and illustrates how climate data, early warning systems and integrated climate services for health can protect people in a warming world.

“And in this age of war, climate stress is also exposing another truth: our addiction to fossil fuels is destabilizing both the climate and global security.  Today’s report should come with a warning label: climate chaos is accelerating and delay is deadly,” said Mr Guterres.

The State of the Global Climate Report 2025 is based on scientific contributions from National Meteorological and Hydrological Services, WMO Regional Climate Centres, United Nations partners and dozens of experts.

“WMO’s State of the Global Climate report seeks to inform decision-making. It is in keeping with the theme of World Meteorological Day because when we observe today, we don’t just predict the weather, we protect tomorrow. Tomorrow’s people. Tomorrow’s planet,” said Celeste Saulo.

Looming catastrophe of climate change

Fossil-fuel companies have become the “godfathers of climate chaos” and should be banned from advertising in every country, the secretary general of the United Nations stated while delivering dire new scientific warnings of global heating.

Speaking in New York this week, António Guterres called on all media to stop enabling “planetary destruction” by taking fossil-fuel advertising money as he warned the world faces “climate crunch time” in its faltering attempts to stem the crisis.

“Many governments restrict or prohibit advertising for products that harm human health,” he said. “I urge every country to ban advertising from fossil-fuel companies. And I urge news media and tech companies to stop taking fossil-fuel advertising.”

In his speech, Guterres announced new data from the World Meteorological Organization (WMO) showing there is an 80 percent chance Earth will breach 1.5C in warming above pre-industrial times in the next five calendar years. 

The WMO says there is a already a 50-50 chance that the global average in the period between 2024 to 2028 will be above 1.5C in warming.

“We are playing Russian roulette with our planet,” he said. “We need an exit ramp off the highway to climate hell.”

According to the European Union’s Copernicus monitoring system, the past 12 months (from June 2023 to May of this year) have already breached this target following a string of months with record-breaking heat, with the average global temperature being 1.63C higher than the pre-industrial average.

Guterres likened the looming catastrophe to the meteor that wiped out the dinosaurs. “We’re having an outsized impact and, in the case of climate, we are not the dinosaurs - we are the meteor. We are not only in danger - we are the danger.”

He admitted that the 1.5C target was “still just about possible” but said there needed to be far greater effort from countries to slash carbon emissions, to boost climate finance to poorer countries, and for the fossil-fuel industry to be made pariahs by governments, the media and other businesses.

“The godfathers of climate chaos - the fossil-fuel industry - rake in record profits and feast off trillions in taxpayer-funded subsidies,” he said. “It is a disgrace that the most vulnerable are being left stranded, struggling desperately to deal with a climate crisis they did nothing to create.

“We cannot accept a future where the rich are protected in air-conditioned bubbles, while the rest of humanity is lashed by lethal weather in unlivable lands.”

Guterres attacked fossil-fuel firms for their meagre investments in cleaner forms of energy and for “distorting the truth, deceiving the public and sowing doubt” about climate science.

He called for global bans on fossil-fuel advertising and for public relations and media companies to cut ties with oil, gas and coal interests.

“These companies should stop acting as enablers to planetary destruction. Stop taking on new fossil-fuel clients and set out plans to drop your existing ones. Fossil fuels are not only poisoning our planet - they’re toxic for your brand.”

The speech was timed to act as a rallying call by the UN which is increasingly concerned that the climate crisis has slipped down the list of priorities for a world racked by war in Ukraine and Gaza, and other economic worries.

A meeting of the powerful G7 group of countries will take place in Italy next week, followed by November’s Cop29 climate summit, to be held in Azerbaijan, along with a G20 gathering in Brazil.

Amid this wrangling the impacts of the climate crisis continue to hit home, with countries including India and the US recently gripped by severe heatwaves. 

A study released this week found that extensive flooding that has devastated parts of southern Brazil, leading to 169 deaths, was made at least twice as likely due to human-caused climate change.

But Guterres urged people not to lose courage or hope. “No country can solve the climate crisis in isolation and we do still have a choice,” he said.

“This is an all-in moment. We can create tipping points for climate progress, or we can career to tipping points for climate disaster.”

He warned that it was now the people of Earth versus the polluters and the profiteers – and it is time for leaders to decide whose side they’re on.

“Tomorrow it will be too late,” Guterres concluded. “Now is the time to mobilise, now is the time to act, now is the time to deliver. This is our moment of truth.”

Professor emeritus of geophysical and climate hazards at University College London, Bill McGuire, agrees and says that as a scientist he is faced with “indifference and a failure to understand the reality of the climate crisis every day.

“We must wake people up. Extreme weather, especially heatwaves and floods, is set to be all-pervasive and will have a colossal impact on our lives and livelihoods,” he warns.

“A recent report by the European Environment Agency warned that climate breakdown will bring ‘catastrophic’ consequences for an unprepared Europe, most notably through heat stress, river flooding and flash floods.

“And this applies equally to the UK. Disruption to transport and utilities, interference with industrial and business operations, serious pressures on food production and supply, and increased burdens on the health service and hospitals, will conspire to make day-to-day living harder and far more unpredictable.”

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A Moment of Truth – UN speech by António Guterres (5 June 2024)
Hothouse Earth – by Bill McGuire (2022)