A new study has worrying conclusions about changes in an essential aspect of the global climate system.
Why it matters: The apparent weakening of the Atlantic Meridional Overturning Circulation (AMOC) – largely as a result of melting ice – is a reminder that climate change may bring nasty surprises in the future.
Driving the news: In a study published in Nature Geoscience On Thursday, researchers reported that the AMOC – a system of ocean currents comprising the Florida Current and the Gulf Stream – is in its “weakest state in more than a millennium.”
- The AMOC is the thermohaline circulation of the oceans and plays an important role in managing the global climate, including keeping temperatures in Europe warmer than they would otherwise be for its latitude.
The big picture: The AMOC has been called the “Achilles’ heel” of the climate and causes drastic changes when turned on and off during Earth’s history.
- It gained a moment of public prominence in the 2004 climate disaster film “The Day After Tomorrow”, where it shut down, devastating major cities around the world and causing severe storms and weather.
Yes but: Nothing near as drastic is expected, even if the current weakened much further, and researchers still have no direct control over the health of the AMOC, which is why they were forced to use proxy data in the study.
It comes down to: The biggest reason to worry about climate change – and act on it – are not the most likely but survivable bad outcomes, but the less likely ones that could be truly existential.