The state of the Atlantic Meridional Overturning Circulation (AMOC) has been a hot topic among climate scientists in recent years. The AMOC is crucial for climate regulation because it pulls warm surface water from the tropics north and sends colder, deeper water south, redistributing large amounts of heat, helping to sustain marine ecosystems and keeping global weather patterns steady. However, most standard AMOC-focused climate models may be missing an important piece of the puzzle—they don't include the growing pulse of freshwater from Greenland ice melt, which could further disrupt the AMOC.

But now, a study published in Science Advances has incorporated the freshwater influx from Greenland's ice melt into a new model. The results show that while the meltwater plays a significant role, it may not push the AMOC over the edge just yet.

To tip or not to tip?,
Most climate models agree that the AMOC will continue to weaken this century, but the abrupt collapse that some models suggest remains debated. A recent Intergovernmental Panel on Climate Change (IPCC) model found that none of the Coupled Model Intercomparison Project phase 6 (CMIP6) models show an abrupt AMOC collapse during the 21st century.

Yet another recent study found that the Atlantic "cold blob" indicated a tipping point was nearing if conditions worsen. Earlier work has suggested that the Greenland meltwater contributes to the weakening of the AMOC, but it's been unclear whether that weakening would lead to an abrupt tipping point in which the AMOC collapses completely or is very difficult to reverse.

"However, it currently remains an open question whether these meltwater-induced AMOC changes are associated with tipping point characteristics such as abruptness and irreversibility. In addition, the physical mechanisms of how Greenland meltwater affects the AMOC beyond 2100 have, to our knowledge, not yet been explored," write the authors of the new study.