Back in 1990, journalist James Burke produced a documentary for PBS called "After the Warming," which looked back from an imagined 2050 to explain how and why palm trees came to grow in Boston. The framing device he used was to set the documentary as an explainer for an important report on the Atlantic thermohaline circulation study due to be released during the broadcast. I won't spoil it for you except to say as pessimistic as Burke was in 1990, he may have been, in fact, overly optimistic:
The Atlantic Ocean’s sensitive circulation system has become slower and less resilient, according to a new analysis of 150 years of temperature data — raising the possibility that this crucial element of the climate system could collapse within the next few decades.
Scientists have long seen the Atlantic Meridional Overturning Circulation, or AMOC, as one of the planet’s most vulnerable “tipping elements” — meaning the system could undergo an abrupt and irreversible change, with dramatic consequences for the rest of the globe. Under Earth’s current climate, this aquatic conveyor belt transports warm, salty water from the tropics to the North Atlantic, and then sends colder water back south along the ocean floor. But as rising global temperatures melt Arctic ice, the resulting influx of cold freshwater has thrown a wrench in the system — and could shut it down entirely.
The study published Tuesday in the journal Nature Communications suggests that continued warming will push the AMOC over its “tipping point” around the middle of this century. The shift would be as abrupt and irreversible as turning off a light switch, and it could lead to dramatic changes in weather on either side of the Atlantic.
The consequences would not be nearly as dire as they appear in the 2004 sci-fi film “The Day After Tomorrow,” in which a sudden shutdown of the current causes a flash freeze across the northern hemisphere. But it could lead to a drop in temperatures in northern Europe and elevated warming in the tropics, Peter Ditlevsen said, as well as stronger storms on the East Coast of North America.
Exactly: palm trees in Boston and the extinction of most food crops in Scotland, Scandinavia, and the Baltics. London in January may only have 6 hours of daylight but it rarely gets below freezing, even though it's at roughly the same latitude as Calgary. If the Atlantic stops bringing warm Caribbean water to the British Isles, the UK will have to invest in snow plows.
The main thing that Burke predicted in his film has come to pass, however: decades of inaction by politicians who have no incentive (other than having to live on the planet) for taking long-term action on climate change. And we're the worst offenders.