James Stewart

To understand conditions before regular temperature measurements began, we must turn to proxy data. The traces of past climate change left behind in slowly accumulating archives, things like ice sheets or seafloor sediments. Proxies like the ratio of oxygen isotopes found in the microscopic skeletons that make up much of the deep floor sediment provide a record of past surface water temperatures.

To understand conditions before regular temperature measurements began, we must turn to proxy data. The traces of past climate change left behind in slowly accumulating archives, things like ice sheets or seafloor sediments. Proxies like the ratio of oxygen isotopes found in the microscopic skeletons that make up much of the deep floor sediment provide a record of past surface water temperatures.

The size of sediment grains on the ocean floor reveal current speeds above it and allow us to reconstruct past sea surface temperatures and other parameters. What they suggest is a long-term weakening of the AMOC since the early or even mid-20th century. Climate models have long predicted its decline in response to global warming, and the physics behind these predictions is understood.

The size of sediment grains on the ocean floor reveal current speeds above it and allow us to reconstruct past sea surface temperatures and other parameters. What they suggest is a long-term weakening of the AMOC since the early or even mid-20th century. Climate models have long predicted its decline in response to global warming, and the physics behind these predictions is understood.

The size of sediment grains on the ocean floor reveal current speeds above it and allow us to reconstruct past sea surface temperatures and other parameters. What they suggest is a long-term weakening of the AMOC since the early or even mid-20th century. Climate models have long predicted its decline in response to global warming, and the physics behind these predictions is understood.

In addition, the paleoclimatic data also strongly points to human activities as the cause, in that AMOC weakening coincides with the period of unprecedented modern global warming. In short, it's very likely that humans have significantly increased the conditions in which the AMOC is prone to being unstable. We can observe several changes here.

In addition, the paleoclimatic data also strongly points to human activities as the cause, in that AMOC weakening coincides with the period of unprecedented modern global warming. In short, it's very likely that humans have significantly increased the conditions in which the AMOC is prone to being unstable. We can observe several changes here.

In addition, the paleoclimatic data also strongly points to human activities as the cause, in that AMOC weakening coincides with the period of unprecedented modern global warming. In short, it's very likely that humans have significantly increased the conditions in which the AMOC is prone to being unstable. We can observe several changes here.

There's a rise in greenhouse gas emissions and arctic amplification. There's also an increasingly enhanced water cycle, intensified by more energy from the sun, which creates more extreme weather like floods and droughts. There's also more evaporation in the subtropics and more precipitation in the high latitudes. Now these things are all happening before we've ever mentioned melting sea ice.

There's a rise in greenhouse gas emissions and arctic amplification. There's also an increasingly enhanced water cycle, intensified by more energy from the sun, which creates more extreme weather like floods and droughts. There's also more evaporation in the subtropics and more precipitation in the high latitudes. Now these things are all happening before we've ever mentioned melting sea ice.

There's a rise in greenhouse gas emissions and arctic amplification. There's also an increasingly enhanced water cycle, intensified by more energy from the sun, which creates more extreme weather like floods and droughts. There's also more evaporation in the subtropics and more precipitation in the high latitudes. Now these things are all happening before we've ever mentioned melting sea ice.

And here comes the big one. The Greenland ice sheet is melting at a rate of around 270 billion tonnes per year, and this is what makes the water less and less salty.

And here comes the big one. The Greenland ice sheet is melting at a rate of around 270 billion tonnes per year, and this is what makes the water less and less salty.

And here comes the big one. The Greenland ice sheet is melting at a rate of around 270 billion tonnes per year, and this is what makes the water less and less salty.

The fresh water dilutes the salty water, and this is salt advection feedback, a positive feedback mechanism that affects the strength of the AMOC, as the major tipping point that ultimately leads to a slowdown or even collapse of the AMOC. In 1961, US oceanographer Henry Stommel recognized how the Atlantic water's salinity leads to an AMOC tipping point.

The fresh water dilutes the salty water, and this is salt advection feedback, a positive feedback mechanism that affects the strength of the AMOC, as the major tipping point that ultimately leads to a slowdown or even collapse of the AMOC. In 1961, US oceanographer Henry Stommel recognized how the Atlantic water's salinity leads to an AMOC tipping point.

The fresh water dilutes the salty water, and this is salt advection feedback, a positive feedback mechanism that affects the strength of the AMOC, as the major tipping point that ultimately leads to a slowdown or even collapse of the AMOC. In 1961, US oceanographer Henry Stommel recognized how the Atlantic water's salinity leads to an AMOC tipping point.

In other words, the AMOC flows because the Northern Atlantic is salty, and it's salty because the AMOC flows. It's chicken and egg, or in more technical terms, a self-sustaining feedback effect, which works the other way around as well. If the northern Atlantic becomes less salty because of an inflow of fresh water, the water becomes less dense and the AMOC slows down.

In other words, the AMOC flows because the Northern Atlantic is salty, and it's salty because the AMOC flows. It's chicken and egg, or in more technical terms, a self-sustaining feedback effect, which works the other way around as well. If the northern Atlantic becomes less salty because of an inflow of fresh water, the water becomes less dense and the AMOC slows down.

In other words, the AMOC flows because the Northern Atlantic is salty, and it's salty because the AMOC flows. It's chicken and egg, or in more technical terms, a self-sustaining feedback effect, which works the other way around as well. If the northern Atlantic becomes less salty because of an inflow of fresh water, the water becomes less dense and the AMOC slows down.