from Planet B media

Modelling striking again on the alleged collapse of the Atlantic meridional overturning circulation (AMOC) and of course, “we’re all going to die!”

1. How long scientists have been predicting AMOC collapse
• The idea that the AMOC could weaken or even collapse dates back to the 1980s.
• In 1987, Wallace Broecker published a landmark paper in Nature linking abrupt climate shifts in the past (seen in Greenland ice cores) to sudden slowdowns of the North Atlantic circulation.
• Since then, climate models and paleoclimate studies have shown that the AMOC is a “tipping element” in the Earth system.
• The IPCC (starting with its Third Assessment Report in 2001) began explicitly warning that a shutdown of the AMOC was a possible outcome of climate change if enough freshwater entered the North Atlantic.
• Today, there’s broad agreement that while a total collapse this century is unlikely but possible, the AMOC is already weakening compared to preindustrial strength.

Comparing apples with apples?

Data shows we are losing ice, perhaps not at the Antarctic at the moment, but with sea level rising at 3 mm per year, its coming from somewhere

So what disrupted the AMOC in the past

Younger Dryas (12,900 years ago)
• Trigger: catastrophic drainage of Lake Agassiz–Ojibway when its ice dam failed.
• Volume: ~10,000–15,000 km³ of freshwater.
• Timeframe:
• Early studies assumed “decades,” but more recent stratigraphic and modeling evidence points to an extremely rapid flood — potentially weeks to months.
• Some lake-sediment records suggest massive discharges equivalent to several Sverdrups (1 Sv = 1 million m³/s of flow), i.e. larger than the Amazon River multiplied many times over.
• Impact: This abrupt freshwater shock essentially “switched off” the Atlantic overturning almost immediately, leading to ~1,000 years of North Atlantic cold conditions.

8.2 ka Event (~8,200 years ago)
• Trigger: final collapse of the Hudson Bay ice dam, releasing the last remnants of Lake Agassiz–Ojibway.
• Volume: ~5,000–10,000 km³.
• Timeframe:
• The meltwater pulse appears to have been very fast — often described as a few months to a couple of years at most.
• Some researchers argue for a “megaflood” lasting only weeks.
• Impact: weakened the AMOC for ~100–150 years, producing abrupt cooling across the North Atlantic region.

Contrast with Today’s Melt
• Modern Greenland melt: ~225–270 km³ per year (spread across decades).
• At this rate, it takes 40 years to reach the same cumulative discharge as the Younger Dryas flood — but crucially, it’s diluted over decades, not weeks.
• This means the AMOC can partially adjust (weaken, freshen gradually) instead of tipping instantly.
• Paleoclimate shows that it’s not just the total volume, but the delivery speed that matters. The system can absorb gradual melt better than a single pulse.

Bullshit models or not? You decide.