Global warming has accelerated: Earth is heating nearly twice as fast as before

Global warming appears to have shifted into a faster phase. The planet's surface temperature is now rising at roughly 0.35°C per decade, nearly twice the rate observed between 1970 and 2015, when warming averaged slightly below 0.2°C per decade. Climate researchers reached this conclusion after comparing results from five independent global temperature datasets.

Extreme heat is becoming one of the most visible manifestations of the acceleration in global warming identified by climate researchers.

The main objective of researchers from the Potsdam Institute for Climate Impact Research (PIK) in Germany was to distinguish an underlying climate trend from natural short-term variability — the "noise" that can temporarily conceal long-term warming or, conversely, produce apparent temperature records.

Long-term global warming does not proceed at a perfectly constant rate. Periods of faster and slower warming lasting around one or two decades can occur because of natural variability. Before the recent acceleration during roughly 2015–2025, for example, global surface temperatures experienced a period of comparatively slow growth between the late 1990s and early 2010s.

To isolate the underlying trend, the researchers adjusted the temperature records for several sources of short-term variability, including the warming influence of El Niño, volcanic eruptions — whose aerosols can temporarily cool the planet by reflecting incoming sunlight — and changes in solar activity.

To improve robustness, they examined several decades of observations from five global temperature datasets, including records maintained by NASA and NOAA, as well as Europe's ERA5 reanalysis dataset produced by the Copernicus Climate Change Service.

After accounting for these natural influences, the statistical confidence that the underlying warming rate had accelerated exceeded 98%. In other words, the researchers found strong evidence that the faster warming is not simply the result of measurement uncertainty or an unusually warm sequence of individual years.

The findings were published in Geophysical Research Letters.

According to the analysis, the change in warming rate became apparent around 2013–2015. The exceptionally hot years of 2023 and 2024 further highlighted the shift, with both years ranking among the warmest ever measured in modern observational records.

The researchers applied two separate statistical approaches. One tested whether the long-term temperature trajectory had developed an upward curvature, while the second attempted to identify a structural change in the warming trend. Both approaches indicated a significant acceleration.

Importantly, the purpose of the study was to measure the changing rate of warming rather than determine its precise causes. Nevertheless, the observed acceleration is consistent with the expected response of the atmosphere and oceans to the continued accumulation of greenhouse gases.

What this could mean for Europe

The consequences of faster global warming are particularly relevant for Europe because the continent has been warming considerably faster than the global average. Recent assessments by European climate agencies have repeatedly identified Europe as the fastest-warming continent, with temperatures increasing at roughly twice the global average over recent decades.

For European countries, continued warming increases the probability and intensity of several interconnected risks: prolonged heatwaves, drought and water stress in southern and central Europe, wildfire conditions around the Mediterranean, declining snow and glacier mass in the Alps, and more intense rainfall events in some regions.

These changes also have economic consequences. Energy systems must cope simultaneously with higher summer cooling demand, changing hydropower availability and increasing weather-related stress on electricity infrastructure. Agriculture faces shifting growing seasons and greater exposure to heat and drought, while European cities increasingly require heat-adaptation measures such as urban greening, shading and cooling infrastructure.

The 1.5°C threshold

If the recently observed warming rate were sustained, the world could move beyond 1.5°C of long-term warming above the pre-industrial average sooner than previously expected.

However, the Paris Agreement's 1.5°C objective refers to long-term average global temperature, rather than a single exceptionally warm year. Individual years can temporarily exceed 1.5°C because of natural variability without necessarily meaning that the Paris threshold has permanently been crossed.

The future warming trajectory will depend primarily on cumulative greenhouse-gas emissions, particularly CO₂ released from coal, oil and natural gas combustion.

A key clarification is that global temperatures would not necessarily continue rising for another century if net CO₂ emissions suddenly fell to zero. Current climate science indicates that global mean temperatures would probably remain approximately stable after net-zero CO₂ is reached, rather than continuing to increase rapidly. Some components of the climate system, however – particularly sea level, ice sheets and ocean heat content – would continue adjusting for centuries or even millennia.

Warming also produces some positive biological effects – but they do not cancel its risks

Climate change does not affect every ecosystem or economic activity negatively. Higher atmospheric CO₂ concentrations can stimulate plant growth through the so-called CO₂ fertilisation effect, and satellite observations have documented substantial global greening during recent decades.

Higher CO₂ can also improve water-use efficiency in many plants and has contributed to increasing productivity in some agricultural systems.

However, these benefits are constrained by nutrient availability, extreme heat, drought, pests and other climate-related stresses. For major crops, the fertilisation effect therefore cannot be considered independently from the broader consequences of rising temperatures and increasingly frequent weather extremes.

The emerging picture is consequently more nuanced than either "global warming is entirely catastrophic" or "higher CO₂ is predominantly beneficial." Rising CO₂ can enhance plant growth under certain conditions, while the same accumulation of greenhouse gases simultaneously drives warming, sea-level rise and increasing climate risks.

The new analysis adds another important dimension to that discussion: the rate at which the climate is changing may itself now be increasing.

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