AMOC And The Planet-Wide Impact Of Ocean Currents

Although it can be hard to tell from looking at the often placid waters of the Earth’s oceans, their currents carry immense amounts of water around the globe on a daily basis, underlying a dynamic system that – much like the Earth’s atmosphere – plays a major role in everything from weather systems to local climates and ecosystems.

Of all these ocean currents the Atlantic meridional overturning circulation (AMOC) is perhaps the most famous, as it is basically the sole reason why Europe has the mild climate that it does today, courtesy of it carrying thermal energy from the equator all the way to the coast off Scandinavia.

Although collapsing an ocean current seems as improbable as stopping the jet streams in the upper atmosphere, it’s actually significantly easier due to how much ocean currents rely on factors that we can fairly easily influence. Over the past decades we have seen worrying signs that the AMOC is indeed weakening, with the million-dollar question being what scenario we’ll be looking at.

While collapsing the AMOC within a decade may be theoretically possible, current models seem to point towards a weakening by about half by the end of this century, with a recent research article by Valentin Portmann et al. inĀ Science Advances going over the various statistical models to come to this conclusion.

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Targeting Rivers To Keep Plastic Pollution Out Of The Ocean

Since the widespread manufacture of plastics began in earnest in the early 1950s, plastic pollution in the environment has become a major global problem. Nowhere is this more evident than the Great Pacific Garbage Patch. A large ocean gyre that has become a swirling vortex full of slowly decaying plastic trash, it has become a primary target for ocean cleanup campaigns in recent years.

However, plastic just doesn’t magically appear in the middle of the ocean by magic. The vast majority of plastic in the ocean first passes through river systems around the globe. Thanks to new research, efforts are now beginning to turn to tackling the issue of plastic pollution before it gets out to the broader ocean, where it can be even harder to clean up.
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Tipping Points In The Climate System: The Worst Kind Of Positive Feedback

With global temperatures continuing to break records in recent years, it’s important to cast an eye towards the future. While efforts to reduce emissions remain in a political quagmire, time is running out to arrest the slide into catastrophe.

Further compounding the issue are a variety of positive feedback loops that promise to further compound the problem. In these cases, initial warming has flow-on effects that then serve to further increase global temperatures. Avoiding these feedback mechanisms is crucial if the Earth is to remain comfortably livable out to the end of the century.

A Multitude of Causes

The issue of climate change often appears as a simple one, with the goal being to reduce greenhouse gas emissions in order to prevent negative consequences for human civilization. Despite this, the effects of climate change are often diffuse and intermingled. The various climate systems of the Earth interact in incredibly complex ways, and there are many mechanisms at play in these feedback effects that could tip things over the edge.

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