Year in Review: The Biggest Climate Headlines of 2025

As 2025 draws to a close, it leaves behind a defining legacy for the planet. The year was marked by unprecedented heat, fragile diplomacy, historic legal breakthroughs, worsening climate impacts, and rare but hopeful conservation successes. From record-breaking temperatures and stalled global agreements to landmark court rulings and signs of ecological recovery, these were the climate stories that shaped 2025—and will influence the decades ahead.

1. 2025 on Track to Be the Joint-Second Warmest Year on Record

According to the European Union’s Copernicus Climate Change Service (C3S), 2025 is virtually certain to end as either the second- or third-warmest year since global temperature records began in the mid-19th century. Data from January to November show global average temperatures standing 0.60°C above the 1991–2020 average, and 1.48°C above pre-industrial levels (1850–1900)—matching the anomaly recorded in 2023.

This sustained warming underscores a disturbing reality: the past decade represents the 10 hottest years ever recorded. The primary driver remains the relentless accumulation of greenhouse gases in the atmosphere, which trap heat and intensify extreme weather. Heatwaves are becoming longer, more frequent, and more deadly, affecting ecosystems, agriculture, infrastructure, and human health.

The milestone year of 2024—now confirmed as the warmest year on record—was also the first to breach the 1.5°C warming threshold set under the Paris Agreement, signaling how rapidly the world is approaching dangerous climatic tipping points.

2. Fossil Fuels Absent From COP30 Final Agreement

Despite growing global pressure, the final agreement at COP30 failed to explicitly commit to phasing out fossil fuels—the primary cause of climate change. Over 80 countries, supported by more than 100 civil society organizations, had urged negotiators to include a clear roadmap for ending fossil fuel dependence. That call was ultimately sidelined.

Under pressure from major oil- and gas-producing nations, including Saudi Arabia and Russia, COP30 President André Corrêa do Lago announced a compromise: a voluntary fossil fuel transition roadmap operating outside the formal UN climate framework. This initiative will be aligned with a Colombia-led “coalition of the willing,” while Colombia separately announced plans to host the first International Conference on the Just Transition Away from Fossil Fuels in April 2026.

COP30, held with 56,118 registered delegates, was the second-largest climate summit in history. Yet its credibility was questioned as nearly 1,600 fossil fuel lobbyists attended, alongside around 2,500 Indigenous representatives, highlighting the imbalance of power still shaping global climate negotiations.

3. Global Plastic Treaty Talks Collapse Again

For the second time, international negotiations aimed at creating a legally binding global plastics treaty ended without agreement. Representatives from 184 countries convened in Geneva in August under the Intergovernmental Negotiating Committee (INC), hoping to resolve disputes over plastic production limits, hazardous chemical regulation, and financial support for developing nations.

The talks followed a previous failure in Busan, South Korea, despite a 2022 UN mandate to finalize a treaty by the end of 2024. While there was broad consensus on the urgency of addressing plastic pollution across its full life cycle, deep divisions—particularly over production caps—prevented progress.

With no clear timeline for renewed negotiations, campaigners warned that delays risk locking the world into decades of escalating plastic waste, with devastating consequences for marine ecosystems and human health.

4. International Court of Justice Issues Historic Climate Ruling

In a landmark moment for climate justice, the International Court of Justice (ICJ) issued an advisory opinion declaring that state actions driving climate change are unlawful under international law. The court ruled that governments have a legal obligation to reduce emissions and may be required to compensate vulnerable nations for climate-related harm.

Describing climate change as an “existential problem of planetary proportions,” ICJ President Yuji Iwasawa emphasized that greenhouse gas emissions are unequivocally caused by human activity and that their impacts are severe, widespread, and irreversible for many communities.

Grounded in binding legal principles, the ruling is expected to catalyze a new wave of climate litigation worldwide, strengthening the hand of small island states, developing countries, and affected communities seeking accountability.

5. Largest Coral Bleaching Event Ever Recorded

Scientists confirmed in 2025 that the world is experiencing the largest mass coral bleaching event in recorded history, affecting nearly 84% of global coral reefs across at least 83 countries and territories. The event began in 2023 and intensified as ocean temperatures reached record highs.

Major reef systems—including Australia’s Great Barrier Reef, the Caribbean, the Red Sea, and large swathes of the Indian and Pacific Oceans—have been severely impacted. Coral bleaching occurs when heat stress causes corals to expel the algae that sustain them, leaving reefs vulnerable to disease and collapse.

According to the World Meteorological Organization, ocean heat content has reached new records for eight consecutive years, with warming rates over the past two decades more than double those observed in the latter half of the 20th century.

6. Climate Change Intensified Deadly Asian Storms

A new attribution study confirmed that climate change “supercharged” the devastating storms that struck South and Southeast Asia in November, killing over 1,800 people and displacing 1.2 million. Two tropical cyclones—Ditwah and Senyar—hit Indonesia and Malaysia simultaneously, triggering catastrophic flooding and landslides.

Researchers found that warmer ocean temperatures amplified rainfall intensity, making such disasters more frequent and deadly. For every 1°C rise in temperature, the atmosphere can hold 7% more moisture, dramatically increasing flood risks in monsoon-prone regions.

7. US Executive Orders Revive Coal Industry

In a controversial move, US President Donald Trump signed executive orders aimed at reviving coal production, rolling back climate regulations enacted under the previous administration. The orders fast-track coal mining leases on federal land and remove barriers to coal-fired power generation.

Critics warned the move undermines global emissions reduction efforts, noting that coal remains the largest single source of fossil fuel emissions, responsible for roughly 40% of global CO₂ emissions. While many nations—including Germany, the UK, and South Korea—have phased out coal, the US policy shift raised concerns about backsliding at a critical moment.

8. High Seas Treaty to Enter Force in 2026

In a rare moment of global cooperation, the UN High Seas Treaty cleared the ratification threshold and will enter into force in 2026. The treaty aims to protect marine biodiversity beyond national jurisdictions by creating Marine Protected Areas covering up to 30% of the high seas.

Currently, only 1% of international waters are protected. The agreement also mandates environmental impact assessments for activities such as deep-sea mining and promotes equitable access to marine genetic resources for developing nations.

9. Green Sea Turtles Removed From Endangered List

In one of 2025’s most hopeful stories, the IUCN reclassified green sea turtles from “endangered” to “least concern,” citing decades of effective conservation. Global populations have steadily recovered since the 1970s thanks to nesting site protection, fishing regulations, and community-led conservation initiatives.

While challenges remain, the recovery demonstrates that sustained, science-based conservation can reverse biodiversity loss.

10. Fossil Fuel Companies Linked to Hundreds of Heatwaves

A groundbreaking study revealed that major fossil fuel and cement companies directly contributed to intensifying hundreds of heatwaves worldwide since 2000. Researchers linked emissions from 180 “carbon major” companies to specific extreme heat events, including deadly heat domes in North America and Europe.

Just 14 companies were found to have caused more than 50 heatwaves each, reinforcing calls for corporate accountability and climate reparations.

Looking Ahead

The climate story of 2025 is one of stark contrasts—between scientific warning and political hesitation, ecological collapse and conservation success, injustice and accountability. As the world moves into 2026, the choices made now will determine whether humanity can still steer away from the most catastrophic outcomes, or whether these headlines will become the new normal.

Source: earhnet.