Collapse of critical Atlantic current is no longer low-likelihood, study finds
Scientists say 'shocking' discovery shows rapid cuts in carbon emissions are needed to avoid catastrophic fallout
www.theguardian.comHere’s the latest from credible sources on AMOC (Atlantic Meridional Overturning Circulation) and its potential collapse risks.
Direct answer
- Recent studies and assessments indicate that the AMOC is weakening and that a complete collapse, while not guaranteed, remains a plausible risk under high- to moderate-emission futures. Some analyses suggest tipping points could be reached within decades, with full shutdown possible within 50–100 years in certain scenarios if emissions remain high or Greenland melt accelerates.[2][3][4]
Context and key points
- What AMOC does: It transports heat northward in the Atlantic and helps keep parts of Europe milder; a shutdown would alter tropical rainfall, affect European climate, and raise sea levels along coastlines.[3][5]
- Current evidence: Multiple lines of evidence point to a weakening trend in the AMOC over the past decade to two, with ongoing debate about timing and reversibility. Some studies emphasize early warning signals indicating proximity to a tipping point, though direct observation remains challenging.[5][8][9]
- Projections by scenario:
- High-emission scenarios: Models consistently show a substantial slowdown and potential shutdown of AMOC after 2100, driven by freshening from Greenland ice melt and reduced ocean heat transport.[3]
- Moderate to low emissions: Some models still project significant weakening or partial shutdown in coming decades, though there is more variability and less consensus on exact timings.[2][3]
- Uncertainties and caveats: Ocean observations have gaps, model representations of ice melt and freshwater input differ, and exact timing of tipping points remains uncertain. Scientists stress that rapid emission reductions could substantially reduce the risk of a catastrophic AMOC collapse.[7][2][3]
Illustrative takeaways
- If AMOC slows or collapses, expect changes such as drier summers in parts of Africa and the Americas, potential cooling or more variable winters in Europe, shifts in tropical rainfall belts, and higher sea level rise on eastern U.S. and other Atlantic coasts.[4][3]
- The message from the scientific community is urgency: reducing greenhouse gas emissions and limiting Greenland ice sheet melt are central to lowering the probability of crossing a collapse threshold.[4][2][3]
Would you like a concise timeline of the major studies and their stated risk levels, or a visualization (e.g., a chart of projected AMOC strength under different emission scenarios) with sources? I can assemble a quick overview or generate a chart if you’d like.