Uploaded August 2025 | Updated September 2026, 2 weeks ago
AMOC Collapse Risk Much Higher, According to New Research: 25%, 37%, 70% for Low to High Emissions
Two new, independent scientific research papers published in the last few days find that risks of AMOC collapse are much higher than previously thought, and will happen sooner than thought.
I chat about this new research, and caution that it does not account for accelerated Greenland melt putting more fresh water into the North Atlantic Ocean, and does not consider effects of collapse of Antarctic sea ice since 2015 and the slowdown of the Antarctic Overturning Circulation.
Please donate to PaulBeckwith.net to support my research and videos connecting the dots on abrupt climate system mayhem.
Main Guardian article: Aug 28, 2025
Collapse of critical Atlantic current is no longer low-likelihood: theguardian.com/environment/2025/aug/28/collapse-critical-atlantic-current-amoc-no-longer-low-likelihood-study?CMP=oth_b-aplnews_d-1
Gulf Stream current at its weakest in 1,600 years: theguardian.com/environment/2025/feb/26/total-collapse-of-vital-atlantic-currents-unlikely-this-century-study-finds
Avoid Gulf stream disruption at all costs: theguardian.com/environment/2018/apr/13/avoid-at-all-costs-gulf-streams-record-weakening-prompts-warnings-global-warming
Climate crisis: Scientists spot warning signs of Gulf Stream collapse: theguardian.com/environment/2021/aug/05/climate-crisis-scientists-spot-warning-signs-of-gulf-stream-collapse
Greenland losing 30m tonnes of ice an hour: theguardian.com/environment/2024/jan/17/greenland-losing-30m-tonnes-of-ice-an-hour-study-reveals
New peer-reviewed science paper: Shutdown of northern Atlantic overturning after 2100 following deep mixing collapse in CMIP6 projections: iopscience.iop.org/article/10.1088/1748-9326/adfa3b/pdf
Abstract
Several, more recent global warming projections in the coupled model intercomparison project 6 contain extensions beyond year 2100–2300/2500. The Atlantic meridional overturning circulation (AMOC) in these projections shows transitions to extremely weak overturning below the surface mixed layer (less than 6 Sv; 1 Sv = 106 m3 s−1) in all models forced by a high-emission (SSP585) scenario and sometimes also forced by an intermediate- (SSP245) and low-emission (SSP126) scenario. These extremely weak overturning states are characterized by a shallow maximum overturning at depths less than 200 m and a shutdown of the circulation associated with North Atlantic deep water formation. Northward Atlantic heat transport at 26°N decreases to 20%–40% of the current observed value. Heat release to the atmosphere north of 45°N weakens to less than 20% of its present-day value and in some models completely vanishes, leading to strong cooling in the subpolar North Atlantic and Northwest Europe. In all cases, these transitions to a weak and shallow AMOC are preceded by a mid-21st century collapse of maximum mixed-layer depth in Labrador, Irminger and Nordic Seas. The convection collapse is mainly caused by surface freshening from a decrease in northward salt advection due to the weakening AMOC but is likely initiated by surface warming. Maximum mixed-layer depths in the observations are still dominated by internal variability but notably feature downward trends over the last 5–10 years in all deep mixing regions for all data products analyzed. This could be merely variability but is also consistent with the model-predicted decline of deep mixing.
New Peer-Reviewed Science paper: Physics-Based Indicators for the Onset of an AMOC Collapse Under Climate Change: agupubs.onlinelibrary.wiley.com/doi/10.1029/2025JC022651
Abstract
The Atlantic meridional overturning circulation (AMOC) is an important tipping element in the climate system. There is a large uncertainty whether the AMOC will start to collapse during the
century under future climate change, as this requires long climate model simulations which are not always available. Here, we analyze targeted climate model simulations done with the Community Earth System Model (CESM) with the aim to develop a physics-based indicator for the onset of an AMOC tipping event. This indicator is diagnosed from the surface buoyancy fluxes over the North Atlantic Ocean and is performing successfully under quasi-equilibrium freshwater forcing, freshwater pulse forcing, climate change scenarios, and for different climate models. An analysis consisting of 25 different climate models shows that the AMOC could begin to collapse by 2063 (from 2026 to 2095) under an intermediate emission scenario (SSP2-4.5), or by 2055 (from 2023 to 2076) under a high-end emission scenario (SSP5-8.5). When the AMOC collapses, the Northwestern European climate changes drastically and this will likely induce severe societal impacts.
Please donate to PaulBeckwith.net to support my research and videos connecting the dots on abrupt climate system mayhem.
AMOC Collapse Risk Much Higher, According to New Research: 25%, 37%, 70% for Low to High Emissions
Two new, independent scientific research papers published in the last few days find that risks of AMOC collapse are much higher than previously thought, and will happen sooner than thought.
I chat about this new research, and caution that it does not account for accelerated Greenland melt putting more fresh water into the North Atlantic Ocean, and does not consider effects of collapse of Antarctic sea ice since 2015 and the slowdown of the Antarctic Overturning Circulation.
Please donate to PaulBeckwith.net to support my research and videos connecting the dots on abrupt climate system mayhem.
Main Guardian article: Aug 28, 2025
Collapse of critical Atlantic current is no longer low-likelihood: theguardian.com/environment/2025/aug/28/collapse-critical-atlantic-current-amoc-no-longer-low-likelihood-study?CMP=oth_b-aplnews_d-1
Gulf Stream current at its weakest in 1,600 years: theguardian.com/environment/2025/feb/26/total-collapse-of-vital-atlantic-currents-unlikely-this-century-study-finds
Avoid Gulf stream disruption at all costs: theguardian.com/environment/2018/apr/13/avoid-at-all-costs-gulf-streams-record-weakening-prompts-warnings-global-warming
Climate crisis: Scientists spot warning signs of Gulf Stream collapse: theguardian.com/environment/2021/aug/05/climate-crisis-scientists-spot-warning-signs-of-gulf-stream-collapse
Greenland losing 30m tonnes of ice an hour: theguardian.com/environment/2024/jan/17/greenland-losing-30m-tonnes-of-ice-an-hour-study-reveals
New peer-reviewed science paper: Shutdown of northern Atlantic overturning after 2100 following deep mixing collapse in CMIP6 projections: iopscience.iop.org/article/10.1088/1748-9326/adfa3b/pdf
Abstract
Several, more recent global warming projections in the coupled model intercomparison project 6 contain extensions beyond year 2100–2300/2500. The Atlantic meridional overturning circulation (AMOC) in these projections shows transitions to extremely weak overturning below the surface mixed layer (less than 6 Sv; 1 Sv = 106 m3 s−1) in all models forced by a high-emission (SSP585) scenario and sometimes also forced by an intermediate- (SSP245) and low-emission (SSP126) scenario. These extremely weak overturning states are characterized by a shallow maximum overturning at depths less than 200 m and a shutdown of the circulation associated with North Atlantic deep water formation. Northward Atlantic heat transport at 26°N decreases to 20%–40% of the current observed value. Heat release to the atmosphere north of 45°N weakens to less than 20% of its present-day value and in some models completely vanishes, leading to strong cooling in the subpolar North Atlantic and Northwest Europe. In all cases, these transitions to a weak and shallow AMOC are preceded by a mid-21st century collapse of maximum mixed-layer depth in Labrador, Irminger and Nordic Seas. The convection collapse is mainly caused by surface freshening from a decrease in northward salt advection due to the weakening AMOC but is likely initiated by surface warming. Maximum mixed-layer depths in the observations are still dominated by internal variability but notably feature downward trends over the last 5–10 years in all deep mixing regions for all data products analyzed. This could be merely variability but is also consistent with the model-predicted decline of deep mixing.
New Peer-Reviewed Science paper: Physics-Based Indicators for the Onset of an AMOC Collapse Under Climate Change: agupubs.onlinelibrary.wiley.com/doi/10.1029/2025JC022651
Abstract
The Atlantic meridional overturning circulation (AMOC) is an important tipping element in the climate system. There is a large uncertainty whether the AMOC will start to collapse during the
century under future climate change, as this requires long climate model simulations which are not always available. Here, we analyze targeted climate model simulations done with the Community Earth System Model (CESM) with the aim to develop a physics-based indicator for the onset of an AMOC tipping event. This indicator is diagnosed from the surface buoyancy fluxes over the North Atlantic Ocean and is performing successfully under quasi-equilibrium freshwater forcing, freshwater pulse forcing, climate change scenarios, and for different climate models. An analysis consisting of 25 different climate models shows that the AMOC could begin to collapse by 2063 (from 2026 to 2095) under an intermediate emission scenario (SSP2-4.5), or by 2055 (from 2023 to 2076) under a high-end emission scenario (SSP5-8.5). When the AMOC collapses, the Northwestern European climate changes drastically and this will likely induce severe societal impacts.
Please donate to PaulBeckwith.net to support my research and videos connecting the dots on abrupt climate system mayhem.
