Climate Science Weekly — March 23, 2026

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Key Research & Findings

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Warming Rate Has Nearly Doubled Since 2015

• Published in: Nature (news analysis)
• Key finding: The rate of global warming has surged since 2015 and is now nearly double what it was in the 1970s, according to a study from the Potsdam Institute for Climate Impact Research (PIK). By removing short-term natural influences — El Niño, volcanic eruptions, and solar cycles — from temperature records, researchers uncovered a clear acceleration in the planet's long-term warming trend beginning around 2015. Earth is now warming at a rate of approximately 0.35°C per decade.
• Why it matters: The finding settles one of the hottest debates in climate science and has profound implications for how quickly the world must act to avoid the most dangerous thresholds of warming. If the rate continues, the 1.5°C threshold above pre-industrial levels could be crossed within a generation.

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Extreme Heat Now Affects One in Three People Globally

• Published in: The Guardian (research report)
• Key finding: Rising temperatures are making it difficult even for young, healthy people to safely perform normal physical tasks in many regions. A new study finds that extreme heat now affects one in three people globally, described by researchers as "a sobering preview" of conditions to come.
• Why it matters: The study demonstrates that the health and labor impacts of climate change are no longer a distant prospect — they are already reshaping daily life for billions of people, with particular severity in tropical and subtropical regions that are least responsible for historical emissions.

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NASA Confirms Three Consecutive Record-Hot Years

• Published in: NASA Scientific Visualization Studio (February 4, 2026)
• Key finding: 2025, 2024, and 2023 were the three warmest years in NASA's 146-year temperature record, according to the GISTEMP v4 Surface Temperature Analysis. The visualization highlights these three years in the context of the full GISTEMP record, showing an unmistakable upward trajectory.
• Why it matters: Three consecutive record years have never previously occurred in the instrumental temperature record, providing clear evidence that warming is accelerating rather than plateauing. The data draws on NOAA GHCN v4 meteorological stations and ERSST sea-surface temperature datasets.

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Climate Data & Observations

The convergence of these data points paints an alarming picture. NASA's GISTEMP record — updated approximately on the 10th of each month — shows not only that recent years have broken records, but that the margin by which they do so has grown. The PIK research adds mechanistic clarity: once natural variability is statistically removed, the underlying forced warming trend is accelerating. The one-in-three figure for heat exposure translates to roughly 2.7 billion people currently experiencing conditions that impair physical safety during peak heat events.

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Policy & Action

• EU Finalizes 90% Emissions Cut Target for 2040: European Union member states gave final approval to a landmark new climate target to slash greenhouse gas emissions 90% by 2040, pressing ahead with the bloc's ambitious climate agenda despite political resistance. The vote cements Europe's position as the world's most ambitious major economy on climate policy, though critics note the target's timeline may still be insufficient given accelerating warming rates.

• 24 US States Sue EPA Over Endangerment Finding Repeal: Twenty-four US states have filed a lawsuit accusing the Environmental Protection Agency of illegally repealing its endangerment finding — the foundational scientific assessment that required the agency to regulate greenhouse gases. The suit, filed March 19, argues the EPA's action is unlawful and would effectively strip the federal government of its primary legal authority to address climate pollution under the Clean Air Act.

• COP Flights Carbon Footprint Increased 25-Fold Over Three Decades: A study published in Communications Sustainability (a Nature portfolio journal) finds that the carbon footprint of air travel to UN climate conferences has increased 25-fold over three decades, driven by growing participation and the reliance on long-distance flights. The paper raises uncomfortable questions about the environmental cost of the very meetings designed to solve the climate crisis and calls for structural reforms to how climate diplomacy is conducted.

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What to Watch Next

The following emerging questions and unresolved issues from this week's coverage deserve close attention in coming weeks:

1. Will the PIK acceleration finding reshape IPCC projections? The study confirming that warming has nearly doubled in pace since 2015 was described in Nature as settling "one of the hottest debates among climate scientists." How this finding is incorporated into the next IPCC Working Group I assessment — and whether it alters near-term temperature pathway projections — will be closely watched.

2. How will US courts handle the EPA endangerment lawsuit? The coalition of 24 states suing the EPA represents the most significant domestic legal challenge to US climate regulation in years. The outcome will determine whether the federal government retains its core legal tool for regulating carbon emissions, with implications for US commitments under international agreements.

3. What does three consecutive record years mean for 1.5°C? With NASA confirming 2023, 2024, and 2025 as the three hottest years on record, climate scientists and policymakers will be scrutinizing whether the 1.5°C threshold — the more ambitious limit set by the Paris Agreement — has effectively been breached on a multi-year average basis, and what this means for the architecture of international climate diplomacy heading into COP31.