Human contribution to global warming highest ever in 2025, says study

📌 Summary:

• Indicators of Global Climate Change (IGCC) assessment confirms 2025 was the third-warmest year on record; human contribution to warming possibly the highest ever
• 2025 global temperature ~1.39°C above the 1850–1900 baseline; of this, ~1.37°C attributable to human activities (mainly greenhouse gases), the rest to natural variation
• Comparison: 2024 (warmest, +1.55°C; human ~1.36°C); 2023 (+1.45°C; human ~1.31°C). WMO had pegged 2025 at ~1.44°C
• Why 2025 was cooler than 2024/23 despite record human forcing: it was a La Niña year (cooler equatorial Pacific) with a general planetary cooling effect
• Human-induced warming rising ~0.27°C per decade; GHG emissions hit an all-time high of 56.8 billion tonnes CO2-equivalent in 2025
• Remaining carbon budget for 1.5°C: only ~130 billion tonnes CO2 from start of 2026 — exhaustible in under 3 years at current rates
• Released during the Bonn (Germany) mid-year climate talks; global action set back by US withdrawal from the 2015 Paris Agreement; a proposal seeks electricity to be ≥35% of final energy by 2035 (now ~20%)
• IGCC (first published 2023) is by independent scientists, several of whom contribute to the IPCC; published in Earth System Science Data

🎯 UPSC Relevance: GS3 Environment — climate science, attribution, carbon budgets, mitigation governance, and the credibility gap in global climate action post-US withdrawal.

📝 Prelims Facts:

• IGCC = Indicators of Global Climate Change (annual, since 2023), published in Earth System Science Data
• 2025 = third warmest (+1.39°C); 2024 warmest (+1.55°C); baseline = 1850–1900
• 2025 GHG emissions = 56.8 bn t CO2-equivalent (record); warming ~0.27°C/decade
• Remaining 1.5°C carbon budget ~130 bn t CO2 from 2026; Bonn talks; Paris Agreement (2015)

🔑 Key Term: Carbon budget — the cumulative CO2 that can still be emitted while keeping warming within a chosen limit (e.g., 1.5°C).