2025 Global Temperature
- Hakan Sener
- Apr 30
- 2 min read
Updated: 11 hours ago
A 2025 report warns 2025 temps may rival 2024’s record highs, as reduced aerosols and high climate sensitivity drive persistent warming.
A new study by James Hansen and Pushker Kharecha finds that despite the expected post-El Niño cooling, 2025 global temperatures may match or even exceed 2024’s record highs. This resilience in warming suggests that climate sensitivity is higher than IPCC estimates and that the cooling effect of aerosols—especially from shipping—has been underestimated in recent decades.
The report argues that the extraordinary warming of 2023–24 was not just a spike from El Niño but the result of ongoing, intensified climate forcing, including a sharp drop in aerosol pollution from ships. If correct, this points to a troubling new normal: record heat without a strong El Niño driver.
Key Findings: Earth’s Warming Engine Is Still Running Hot
2025 Global Temperatures Likely to Stay at or Above +1.5°C
February and March 2025 were slightly cooler than the same months in 2024, but declines have been modest.
Even with the end of El Niño and a shift to ENSO-neutral conditions, 2025 could challenge the 2024 global temperature record.
El Niño Was Not the Main Driver of 2023–24 Heat
Hansen’s team finds that El Niño accounted for only half of the 2023–24 warming spike.
The rest likely came from reduced aerosol pollution, especially following 2020 shipping regulations, which allowed more solar energy to reach Earth’s surface.
Aerosol Decline and High Climate Sensitivity Explain the Surge
Less pollution = more sunlight reaching Earth = more warming.
The study estimates aerosol forcing reduction at ~0.5 W/m², focused in mid-latitude oceans.
With an assumed climate sensitivity of 4.5°C, Earth’s response to this new forcing is still playing out.
Why Is Warming So Persistent?
The team removed the long-term warming trend and El Niño signal from the global temperature record to reveal a decade-long anomaly starting in 2015, culminating in an additional 0.3°C warming by 2023.
This pattern doesn’t match China’s slower aerosol reductions, but it closely matches ship emissions cuts, both in timing and location (35°–50°N in the Atlantic and Pacific). The implication: removing aerosols too quickly, without reducing greenhouse gases, can temporarily accelerate warming.
Implications: The IPCC May Be Underestimating Climate Risk
The IPCC's reliance on global climate models (GCMs) may be muting true sensitivity and aerosol forcing.
Hansen’s analysis shows that IPCC model tuning practices (like emergent constraints) risk underrepresenting real-world warming.
Paleoclimate data and modern observations support a climate sensitivity of 4.5°C ± 0.5°C, significantly higher than the IPCC’s 3°C baseline.
A Warming Plateau Isn’t Coming—It’s a Climb
The expectation that 2025 would bring cooling after El Niño is not being met. Instead, continued high temperatures in a neutral ENSO year signal deeper systemic warming.
The study suggests that current policies and projections may be too conservative, underplaying both the speed and scale of climate change. If climate sensitivity is indeed higher and aerosols have been masking more warming than thought, urgent reevaluation of climate policy, mitigation speed, and carbon pricing is needed.
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