The decade from 2015 to 2025 has been confirmed by the World Meteorological Organization (WMO) as the hottest on record, with the past 11 years (2015–2025) being the warmest consecutive years in the WMO’s 176-year dataset.
In its latest edition of the State of the Global Climate report, the UN agency confirmed that the past 11 years (2015–2025) were the hottest on record. “When history repeats itself eleven times, it is no longer a coincidence. It is a call to act,” said UN Secretary-General António Guterres.
Global temperatures have consistently exceeded pre-industrial levels, with recent years showing accelerated warming due to greenhouse gas accumulation. Additionally, according to all datasets, the past three years have been recorded as the hottest on record, with the 2023-2025 average temperature around (± 0.13°C) above the 1850-1900 pre-industrial average.
The Implications Reach Hundreds, if not Thousands, of Years
These results point to implications far beyond our need to turn up the AC. These world-wide temperature increases have implications that reach hundreds, if not thousands, of years.
As Earth.org reports, the WMO data comes just weeks after another study provided the first concrete evidence that global warming is actually accelerating. In the paper, researchers said that the Earth has warmed around 0.35C in the decade to 2025, compared to less than 0.2C per decade on average between 1970 and 2015.
Rising global temperatures, a direct consequence of human-made greenhouse gas emissions, have led to an increase in both the frequency and intensity of some weather and climate extremes since pre-industrial times, including heatwaves, heavy rainfall and tropical cyclones as well as droughts.
Extreme weather drives food insecurity, which itself then leads to social instability and large-scale displacement of people globally, affecting the ability of communities to mitigate the impacts of climate change and adapt to them, the report said.
“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 WMO Secretary-General Celeste Saulo.
A study by charity Christian Aid last December confirmed that record-breaking heatwaves, tropical cyclones, and rainfall made 2025 one of the costliest years for climate disasters, with the 10 costliest disasters alone racking up economic losses of $120 billion.
‘State of Emergency’
Guterres warned that the planet is “in a state of emergency”, with every key climate indicator “flashing red.”
Just like the atmosphere, oceans, which absorb approximately 90% of excess heat from greenhouse gases, are also warming at record speed. According to the WMO report, each of the past nine years has set a new record for ocean heat content, with the warming rate of the past two decades (2005–2025) being twice that observed over the period 1960–2005. It added that nearly 90% of the ocean experienced at least one heatwave last year.
The consequences of ocean warming cannot be overstated. Besides directly affecting marine ecosystems like corals and reducing the ability of the ocean to trap carbon dioxide, warm waters fuel tropical storms and accelerate sea-ice loss in the polar regions, which in turn raises sea levels.
In 2025, the ice sheets on Antarctica and Greenland continued to lose significant mass, while Iceland and the Pacific coast of North America experienced “exceptional” glacier mass loss, the report said.
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