As we bid farewell to 2025, Earth.Org takes a look back at the most significant climate news and events that shaped the past year.
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1. 2025 on Track to Be Joint-Second Warmest Year on Record
2025 is on track to be the joint-second hottest year on record, marking a continuation of the exceptionally high warming trend the world has witnessed in the past decade, according to the European Union’s Earth observation program.
In its December bulletin, the Copernicus Climate Change Service (C3S) said this year is “virtually certain” to finish as either the second- or third-warmest year since records began around 1850. “The global average temperature anomaly for January to November 2025 stands at 0.60C above the 1991–2020 average, or 1.48C above the 1850–1900 pre-industrial reference. These anomalies are identical to those recorded for the full year 2023, currently the second warmest year,” the bulletin read.
The increase in extreme heat is a direct result of our warming planet, which is driven by greenhouse gases that trap heat in the atmosphere. This raises Earth’s surface temperature, leading to longer and hotter heatwaves.
The relentless growth of greenhouse gas levels in the atmosphere has coincided with a steady rise in global temperatures, with the last 10 years making up the top 10 hottest years on record.
2024 now tops the ranking, beating 2023. It was also the first year above 1.5C, the critical global warming temperature threshold set in the Paris Agreement.
2. No Mention of Planet-Warming Fossil Fuels in COP30 Agreement
The demand from around 80 developed and developing countries for an end to the use of fossil fuels –the biggest cause of climate change – was left out of the final COP30 agreement, after two intense weeks of discussions and twists and turns. It comes despite an unprecedented number of countries (more than 80 and led by Colombia) and more than 100 organizations, explicitly asked the presidency to develop a roadmap to transition away from fossil fuels.
Under pressure from major petrostates, including Saudi Arabia and Russia, COP30 President André Corrêa do Lago ultimately announced a compromise: a voluntary “roadmap” for transitioning away from fossil fuels. This roadmap will proceed outside the formal UN process and be merged with the plan of the Colombia-led “coalition of the willing.” Separately, Colombia announced it will host the world’s first International Conference on the Just Transition Away from Fossil Fuels in April.
With 56,118 delegates registered, the 30th edition of the United Nations Conference of the Parties (COP) was the second-largest COP in history, behind only COP28 in Dubai, which was attended by more than 80,000 people. Among them were some 2,500 Indigenous people and about 1,600 fossil fuel lobbyists.
3. ‘Abject Failure’: Global Plastic Treaty Negotiations End Without Deal For Second Time
A meeting that was supposed to culminate in a global treaty to curb plastic pollution long in the making ended without a deal for the second time.
Representatives from 184 countries met in Geneva, Switzerland, in August to resolve outstanding disagreements on capping plastic production, managing plastic products and hazardous chemicals, and financing to support the implementation of the treaty in developing countries. It was supposed to be the second and final session of the fifth meeting of the Intergovernmental Negotiating Committee (INC), after a treaty failed to materialize at last year’s talks in Busan, South Korea.
The INC was set up in response to a UN Environment Assembly resolution in March 2022 requesting the adopt a legally binding global plastics treaty by the end of 2024. According to the resolution, the instrument could include “both binding and voluntary approaches, based on a comprehensive approach that addresses the full life cycle of plastic.”
It remains unclear when and how the negotiations will continue.
4. World’s Top Court Lays Out Historic Protections For Climate-Impacted Nations in Landmark Ruling
In July, the International Court of Justice (ICJ), the principal judicial organ of the United Nations, delivered its long-anticipated advisory opinion on the obligations of states in respect of climate change on Wednesday. It ruled that government actions driving climate change are illegal and states are legally bound to cut their emissions and compensate vulnerable nations for the harm they have caused.
Climate change poses an “existential problem of planetary proportions,” and those responsible for it can be held accountable for their action and inaction, the world’s top court said.
Presenting the opinion at the Peace Palace in The Hague, the court’s President Yuji Iwasawa said greenhouse gas emissions are “unequivocally” caused by human activities. “The consequences of climate change are severe and far-reaching. They affect both natural ecosystems and human populations. These consequences underscore the urgent and existential threat posed by climate change,” he said.
Grounded in binding international law, the opinion is set to spark a chain reaction that accelerates climate litigation on a global scale.
5. Scientists Confirm Largest Coral Bleaching Event on Record Affecting Nearly 84% of World’s Reefs
The world’s coral reefs are undergoing a mass coral bleaching event that began in 2023 and became the largest event ever recorded. It is the fourth mass coral bleaching event ever recorded and the second to occur in the last 10 years.
Some 83.7% of the world’s coral reef area across at least 83 countries and territories have been impacted by bleaching-level heat stress since January 2023, the US National Oceanic and Atmospheric Administration (NOAA) announced last week.
Among the areas affected were Australia’s Great Barrier Reef – the world’s largest coral reef system, Florida, the Caribbean, Brazil, the eastern Tropical Pacific, large areas of the South Pacific, the Red Sea, the Persian Gulf; and the Gulf of Aden. Widespread bleaching has also been confirmed across other parts of the Indian Ocean basin, NOAA said.
Coral bleaching occurs as a heat stress response from rising ocean temperatures, which drives algae away from coral reefs, causing reefs to lose their vibrant colors. Each of the past eight years has set a new record for ocean heat content, according to the World Meteorological Organization (WMO). The rate of ocean warming over the past two decades (2005-2024) is more than twice that in the period 1960-2005.
6. Climate Change ‘Supercharged’ Deadly Asian Storms That Killed More Than 1,800, Study Finds
The heavy monsoon rains and storms that triggered deadly floods across several South and Southeast Asian nations in late November were “supercharged” by climate change, a new attribution study has concluded.
More than 1,800 people have died and some 1.2 million were left stranded after two overlapping tropical cyclones – Ditwah and Senyar – hit Indonesia’s Sumatra region and Peninsular Malaysia simultaneously, triggering deadly floods and landslides. It is one of the deadliest weather-related disasters in recent history, hitting one of the most climate vulnerable regions on Earth that is used to dealing with strong monsoon rains.
New research by the World Weather Attribution group confirmed that climate change is making cyclones like Ditwah and Senyar more frequent and the associated rainfall more intense.
The storm developed over North Indian Ocean waters that were 0.2C warmer than the historical 1991-2020 average and that would have been 1C cooler without human-caused climate change. As ocean surfaces warm, so does the air above it, causing water to be carried up to high altitudes to form clouds, while leaving a low pressure zone beneath causing more air to rush in. The warmer the air, the more water it can hold: for every extra degree Celsius of warming, air can hold 7% more moisture
7. Trump Signs Executive Orders to Revive ‘Beautiful Clean Coal’ in Blow to US Emissions Reduction Efforts
In April, US President Donald Trump signed four executive orders aimed at reviving coal, the dirtiest fossil fuel, and eliminate Biden-era laws meant to curb greenhouse gases both within states and nationwide. The White House said the orders will invigorate the coal industry.
Standing in front of a group of coal miners at the White House, Trump said that his administration “will rapidly expedite leases for coal mining on federal lands” and “streamline permitting.”
The order paving the way for all this describes coal as “beautiful,” “clean,” “abundant and cost effective,” and capable of meeting the nation’s rising electricity demand. It directs federal agencies to identify and eliminate policies that discourage investment in coal production and coal-fired electricity generation.
But the order fails to mention that coal, the dirtiest fossil fuel, is the single-largest source of fossil fuel carbon emissions (40%), responsible for over 0.3C of the 1.2C increase in global average temperatures since the Industrial Revolution, and a major contributor to air pollution.
In fact, nations worldwide are turning away from coal. Nearly 60 countries have drastically scaled back their plans for building coal-fired power plants since the Paris Agreement was passed in 2015, including some of the world’s biggest coal users like Turkey, Vietnam, and Japan. Nations including Germany, South Korea, and the UK phased out coal altogether.
8. ‘Historic’ UN-Led High Seas Treaty to Take Effect in 2026 as Ratification Threshold Cleared
The UN High Seas Treaty, the world’s first treaty to protect and conserve marine biodiversity in international waters adopted in 2022, will enter into force next year after clearing the ratification threshold in September.
Formally known as the Agreement under the United Nations Convention on the Law of the Sea on the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction, or BBNJ Agreement, the treaty is centered around the creation of Marine Protected Areas (MPAs) on the high seas to preserve marine biodiversity. The text, two decades in the making, aims to protect 30% of the high seas. Currently, only 1% of the high seas are protected, leaving marine life vulnerable.
While 142 countries and the European Union signed the treaty since it opened for signature in September 2023, a minimum of 60 ratifications were required for the agreement to come into force. The threshold was cleared last week, when Sri Lanka, St. Vincent and the Grenadines, Sierra Leone and Morocco ratified it.
Along with the creation of marine protected areas in international waters, the treaty also requires economic activity on the high seas, such as planned deep sea mining for transition materials, to present environmental impact assessments. It will also promote equity for developing countries through greater knowledge sharing and technology access, strengthening capacity, and ensuring the equitable access and sharing of the benefits of marine genetic resources.
9. Green Sea Turtles No Longer Endangered Species in Major Conservation Win
Green sea turtles are bouncing back thanks to decades of sustained conservation action, the International Union for Conservation of Nature (IUCN) announced in October.
The species’ latest assessment was carried out in December 2024 and showed that the global population has increased since the 1970s, leading to its reclassification on the IUCN Red List of Threatened Species from “endangered” to “least concern”.
Established in 1964, the list is one of the world’s most comprehensive source of information on the global extinction risk status of animal, fungus and plant species. It counts 172,620 species, of which 48,646 are threatened with extinction.
“Conservation efforts have focused on protecting nesting females and their eggs on beaches, expanding community-based initiatives to reduce unsustainable harvest of turtles and their eggs for human consumption, curtailing trade, and using Turtle Excluder Devices and other measures to reduce the accidental capture of turtles in fishing gear,” the IUCN said in a press release.
10. Fossil Fuel Companies Intensified Hundreds of Heatwaves Worldwide This Century
The world’s largest fossil fuel and cement producers have intensified hundreds of heatwaves worldwide this century, according to a first-of-its-kind study.
Researchers looked at 213 heatwaves that occurred between 2000 and 2023 across 63 countries. Using a well-established extreme event-based attribution framework, they first looked at how more intense and more likely these events were made by climate change. Then, they identified individual contributions from 180 major fossil fuel and cement companies—which they refer to as carbon majors— using these companies’ emissions data.
For the first time, individual companies were linked to specific, sometimes deadly heatwaves, such as the 2021 Pacific Northwest heat dome and the 2023 European heatwaves.
14 companies alone polluted enough to individually cause over 50 heatwaves, which scientists say would have been virtually impossible without climate change. These include Saudi Aramco, Gazprom, ExxonMobil, Chevron, BP, and Shell.
The Intergovernmental Panel on Climate Change (IPCC) has warned that human-caused climate change, which is primarily driven by greenhouse gases, has increased the frequency and intensity of heatwaves since the 1950s. Every heatwave in the world is now made stronger and more likely to happen because of human-caused climate change.
