From the quoted article:
René van Westen watched in alarm as freshwater from a melting Arctic poured into the North Atlantic, diluting the normally dense and salty sea. The influx gradually slowed the aquatic conveyor belt that circulated water throughout the ocean basin, until, in the blink of an eye, the entire system shut down. Temperatures in North America and Europe dropped several degrees in a matter of decades. Global weather patterns shifted, depriving Africa and Asia of vital monsoon rains.
This cataclysm was happening only in a computer simulation — the product of a complex model that scientists use to understand the effects of climate change. But it was the first time anyone had used this particular model to show how the Atlantic Ocean’s sensitive circulatory system can collapse, said Van Westen, a climate scientist at Utrecht University in the Netherlands. And it hinted that the ocean might be on course for a “tipping point” ending in abrupt and irreversible change.
