Global warming has accelerated since 2015, study finds

Overview

Updated 1 hour ago

The planet warmed about 0.35°C per decade over the past ten years, nearly twice the pace from 1970 to 2015. A study published this week is the first to show that increase is statistically real, not an artifact of El Niño or a few hot years.

If the rate holds, the 1.5°C threshold in the Paris Agreement arrives years earlier than projected in 2015. The finding also sharpens a dispute among climate scientists about how much of the recent heat is human-caused and how much is natural variation.

Why it matters

A faster warming rate moves the 1.5°C deadline years closer and changes how quickly countries must cut emissions.

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Key Indicators

0.35°C per decade

Recent warming rate

Average global surface warming over the past decade, roughly 2015-2025.

0.2°C per decade

1970-2015 warming rate

The average pace over the four and a half decades before the acceleration.

98%

Statistical confidence

Confidence that the acceleration is real after adjusting for natural variability.

Independent datasets

NASA, NOAA, HadCRUT, Berkeley Earth and ERA5 all show the acceleration.

1.44°C

Current warming above preindustrial

Copernicus estimate of the global average in 2026.

Voices

Curated perspectives — historical figures and your fellow readers.

People Involved

Stefan Rahmstorf

Climate researcher at the Potsdam Institute for Climate Impact Research; lead author

Lead author of the 2026 acceleration study

Grant Foster

Climate statistician; co-author

Co-author of the 2026 study

Zeke Hausfather

Climate scientist and Carbon Brief contributor

Skeptical of the 0.35°C per decade estimate

Organizations Involved

Potsdam Institute for Climate Impact Research (PIK)

Research institute

Published the 2026 acceleration study

A German climate research institute that produced the 2026 study on warming acceleration.

Copernicus Climate Change Service (C3S)

European Union climate monitoring service

Tracks global temperature and projects the 1.5°C timeline

The EU's climate monitoring service, which publishes monthly global temperature data.

Timeline

December 2015 October 2026

4 events Latest: 4 days ago

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October 2026
Study finds warming accelerated since 2015
Latest Study

PIK researchers report a warming rate of about 0.35°C per decade, nearly double the 1970-2015 pace, with 98% confidence.
4 days ago
Copernicus moves 1.5°C projection to 2029
Projection

The service says the threshold is now about three years away, versus 27 years in 2015.
4 days ago
2024
2023 and 2024 become the hottest years on record
Climate record

Both years set global temperature records, partly because of El Niño and a solar maximum.
2024
December 2015
Paris Agreement sets 1.5°C goal
Treaty

Countries adopt the Paris Agreement, aiming to limit warming to 1.5°C above preindustrial levels.
December 2015

Scenarios

Warming rate holds near 0.35°C per decade through 2030

Possible Resolves by Jan 1, 2031

Discussed by: Potsdam Institute researchers and Carbon Brief

If the adjusted trend persists, independent datasets will show the 2025-2030 warming rate staying well above the 1970-2015 average. That would confirm the acceleration is a lasting shift, not a short-term fluctuation.

Acceleration proves temporary as rate falls back toward 0.2°C per decade

Unlikely Resolves by Jan 1, 2031

Discussed by: Climate scientist Beaulieu and other researchers cited by Carbon Brief

Natural variability or a pause in emissions growth could slow the measured rate. Beaulieu said continued monitoring is needed to know whether the acceleration lasts.

1.5°C long-term threshold formally breached before 2035

Possible Resolves by Jan 1, 2036

Discussed by: Copernicus Climate Change Service and Carbon Brief

A single hot year does not breach the Paris Agreement, which refers to long-term warming. If the accelerated rate continues, the 20-year average could cross 1.5°C within a decade.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

1998-2013

The global warming 'hiatus' debate (1998-2013)

Global average surface temperatures rose more slowly than in the 1980s and 1990s, prompting claims that warming had paused. Later research attributed much of the slowdown to La Niña, a solar minimum, volcanic aerosols and heat uptake by the oceans.

Then

The apparent pause became a political talking point and a test case for climate models.

Now

Scientists improved methods for separating natural variability from the human-caused trend, the same problem the 2026 study addresses.

Why this matters now

The hiatus showed how natural swings can hide or mimic changes in the warming rate. The new study tries to strip those swings out before testing for acceleration.

1958

Keeling Curve begins continuous CO2 monitoring (1958)

Charles Keeling began measuring atmospheric carbon dioxide at Mauna Loa, Hawaii. The record showed CO2 rising steadily year after year, with a sawtooth seasonal pattern.

Then

The measurements gave the first clear, continuous evidence of rising CO2.

Now

The Keeling Curve became the backbone of climate monitoring and a model for long-term environmental records.

Why this matters now

It shows why long, carefully calibrated records matter: short windows can mislead, while decades of data reveal the trend.

December 2015