What it is
The Sixth Assessment Report (AR6) Synthesis, released in 2023, represents the most comprehensive scientific assessment of climate change ever produced. It synthesizes findings from three Working Group reports and three Special Reports, drawing on over 14,000 cited studies. The Summary for Policymakers distills this into 36 pages of key findings.
Why we picked this
This is the scientific bedrock under every climate discussion. When someone questions the science, the AR6 is the answer. The synthesis is also surprisingly readable for a UN document, and the headline statements are unambiguous: human influence on the climate system is unequivocal.
Key takeaways
- Global surface temperature has increased faster since 1970 than in any other 50-year period over at least the last 2,000 years.
- To limit warming to 1.5C, global CO2 emissions need to decline 43% by 2030 and reach net zero by the early 2050s.
- The window for action is narrowing but not closed: the report identifies feasible, cost-effective mitigation options in every sector that could halve emissions by 2030.