Last year was the hottest on record, with the highest ocean heat, record sea level rise, largest glacier loss, and the highest number of people displaced by climate impacts, the World Meteorological Organization (WMO) concludes in its latest report packed with alarming superlatives.

In its 31st annual State of the Climate report, the WMO confirms [pdf] that 2024 was the first calendar year where average global warming exceeded 1.5°C above the pre-industrial era, making it “the warmest year in the 175-year observational record.” It follows a trend where each of the past 10 years, 2015–2024, “were individually the 10 warmest years on record.”

The long-term warming average is estimated at 1.34°C to 1.41°C above the pre-industrial baseline, which means we are “getting closer to the 1.5°C Paris Agreement goal, but not yet passing it,” the WMO writes in a release. These record-breaking temperatures were “mainly due to the ongoing rise in greenhouse gas emissions (GHGs), coupled with a shift from a cooling La Niña to warming El Niño event.”

In 2023, the latest year for which global data are available, the production and combustion of fossil fuels drove atmospheric carbon dioxide to 151% of pre-industrial levels. Fossil fuel use, as well as high-emitting agriculture and waste practices, also drove unprecedented atmospheric methane and nitrous oxide levels—to 266% and 124% of pre-industrial levels, respectively. 

All told, GHG concentrations in 2023 were at their “highest level in 800,000 years,” the WMO says.

Oceans Get Hotter, Higher, More Acidic

The Earth’s oceans, which trap around 90% of the extra heat generated by GHGs, were also the hottest on record. “Over the past eight years, each year has set a new record for ocean heat content, and the rate of ocean warming is now twice as fast as it was before 2005,” the WMO reports.

Ocean warming degrades marine ecosystems—from coral bleaching to the forced migration of fish to cooler waters—weakens marine carbon sinks, fuels tropical and subtropical storms, and melts ice sheets in polar regions.

Sea levels are also trending inexorably upwards, reaching a record high in 2024, partly due to ice melt and partly because warmer water takes up more space.

The oceans also continue to acidify, absorbing roughly 25% of the anthropogenic carbon dioxide emitted between 2014 and 2023. This harms marine life, and by extension, the humans that depend on the ocean for food and livelihoods, the WMO warns.

Glaciers in Free Fall

As confirmed by a ground-breaking study released in late February and reiterated in the State of the Climate report, the last three years witnessed the largest loss of glacier mass on record.

In response to the crisis, the United Nations General Assembly has proclaimed 2025 the International Year of Glaciers’ Preservation and established March 21 as the annual World Day for Glaciers.

“Five of the past six years have seen the most rapid glacier retreat on record,” the WMO states [pdf] in a press release marking the inaugural event. But for several of the icy mountain giants, the window of protection has closed: they “will not survive the 21^st century.”

“Accelerating glacier melt risks unleashing an avalanche of cascading impacts on economies, ecosystems and communities, not just in mountain regions but at global level,” the WMO writes. The loss of the world’s “water towers” threatens the water supply of hundreds of millions of people downstream. Melting glaciers also increases the risk of catastrophic flooding and contributes to sea level rise.

Nearly a Million Displaced

The State of the Climate Report reveals that acute flooding and severe storms, plus sea level rise and groundwater salinization, put 824,500 people on the move for safer places in 2024, “the highest number of newly-displaced people since 2008.” Included in that number were some 100,000 people in Mozambique displaced by Tropical Cyclone Chido in late December.

The report lists 151 unprecedented extreme weather events in 2024, reports the Guardian. The inventory includes extreme heat in Japan, Western Australia, Iran, and Mali, record rain that led to floods in Italy, landslides amid torrential weather in Senegal, and flash flooding in Pakistan and Brazil.

The Guardian also lists destructive typhoons and storms in the Philippines, Florida, and Vietnam, adding that “many more unprecedented events will have passed unrecorded.”

‘What Can We Do?’

The WMO’s “story map” communicates its key findings across six subject headings: atmosphere, land, ocean, cryosphere, extreme events, and risks and impacts. A seventh heading, titled “What Can We Do?”, guides readers through a series of urgently necessary climate actions, at both policy and personal levels.

Above all else, humanity needs to stop adding climate pollution to the atmosphere, the WMO writes.

“Without immediate and deep GHG emissions reductions across all sectors and regions, it will be impossible to keep warming below 1.5° C.”

The WMO notes that global renewable energy capacity share increased by nearly 50% in just a year—the highest growth rate in two decades. Climate finance also increased, reaching almost US$1.3 trillion annually in 2021-2022, and “nearly doubling compared to 2019-2020 levels.”

But to keep to warming to 1.5°C, annual climate finance investments will have to reach “almost US$9 trillion by 2030 and a further US$10 trillion through to 2050.”

Editor’s Note: This story was updated on March 25 to include details about the International Year of Glaciers’ Preservation.