Climate Science: Attribution, Tipping Points and IPCC — 2026-09-19
A major international study published this week confirms that Greenland and Antarctica have lost over 12 trillion tonnes of ice since 1979, driving sea-level rise and accelerating global warming feedback loops. Simultaneously, new research highlights the critical distinction between the *rate* of warming and the *magnitude* for AMOC stability, suggesting earlier tipping points than previously modeled. These findings arrive as the remaining carbon budget for 1.5°C is estimated to be nearly exhausted, intensifying pressure on the upcoming IPCC Seventh Assessment Report.
Climate Science: Attribution, Tipping Points and IPCC — 2026-09-19
Top developments
Satellite data confirms 12 trillion tonnes of ice loss since 1979
New analysis from the Global Carbon Project and satellite observations reveals that Greenland and Antarctica have collectively lost approximately 12.5 trillion tonnes of ice between 1979 and 2023. This massive loss has already contributed to a global mean sea-level rise of over 3 centimeters, with acceleration observed primarily after the 1990s. The study, widely reported by the Los Angeles Times and Euronews on September 16–18, underscores the irreversible nature of current melt rates and provides critical baseline data for attribution studies linking specific extreme weather events to oceanic thermal expansion.
AMOC stability depends on warming rate, not just magnitude
Recent German-language reporting on new climate models indicates that the Atlantic Meridional Overturning Circulation (AMOC) may collapse earlier than previously thought if the speed of warming exceeds certain thresholds, regardless of the final temperature reached. A study highlighted by Focus Online and Futurezone suggests that rapid warming disrupts the salinity balance faster than the system can adjust, posing immediate risks to European climate stability. This challenges previous IPCC assumptions that focused primarily on long-term equilibrium temperatures, urging the IPCC AR7 to incorporate "rate-of-change" metrics into tipping point assessments.
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Natural feedback loops could worsen warming by 30%
A new study reported by The Guardian on September 10 finds that emissions of methane and CO2 from natural sources (such as thawing permafrost and wetlands) are creating positive feedback loops that could exacerbate global warming by an additional 30%. This finding is critical for attribution science, as it suggests that observed warming may be partially driven by natural systems reacting to initial anthropogenic forcing, complicating the separation of human vs. natural causes in specific extreme events. The results highlight the urgency of reducing anthropogenic emissions to prevent triggering these self-reinforcing cycles.
Local view
In China, media outlets including Sina News and Oriental Daily have focused heavily on the implications of ice sheet thresholds for national coastal security. Reports published within the last 24 hours emphasize that limiting global warming to 1.5°C–2.0°C is critical to preventing the irreversible collapse of the Greenland and Antarctic ice sheets, which would trigger sea-level rises of up to 7.5 meters. Chinese stakeholders are using these figures to advocate for more aggressive domestic carbon neutrality targets ahead of COP31.
Context & numbers
- Remaining Carbon Budget: The remaining budget for a 50% likelihood of staying below 1.5°C is approximately 50 GtC (170 GtCO2), which will be exhausted in about four years at current emission rates.
- Warming Rate: After removing El Niño and volcanic effects, global warming has accelerated to ~0.35°C per decade over the last ten years, up from ~0.2°C per decade in 1970–2015.
- Temperature Record: August 2026 was tied with July 2023 as the joint hottest month on record globally, according to the Copernicus Climate Change Service.
On the radar
- IPCC AR7 Preparation: The American Meteorological Society recently published insights for the forthcoming IPCC Seventh Assessment Report, focusing on how tipping point science should inform National Meteorological and Hydrological Services.
- Positive Tipping Points: Scientists are increasingly studying "positive tipping points" where clean energy transitions could trigger cascades of progress, potentially offsetting some negative climate impacts through reduced pollution and ecosystem recovery.
This content was collected, curated, and summarized entirely by AI — including how and what to gather. It may contain inaccuracies. Crew does not guarantee the accuracy of any information presented here. Always verify facts on your own before acting on them. Crew assumes no legal liability for any consequences arising from reliance on this content.
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