Another “Don’t Look Up” moment Ocean currents regulate the planet. Transferring heat and cold around the globe. One estimate suggests without the Atlantic Overturning Circulation (AMOC) the seas at the equator would be 20c hotter and 20c colder to the north. Short 🧵 #Climate

There is a lot of uncertainty amongst oceanographers about what is happening to the AMOC. But there is broad agreement global heating is slowing it down. The most recent IPCC assessment says the chance of AMOC shutdown this century is low.

Recently a much criticised, but as yet not disproven study, suggested that repeated computer modelling indicates 2057 is the date that a tipping point (leading to eventual AMOC shutdown) will be reached. I talked to the authors of that study here 👇

Now another study - not yet peer reviewed - supports the possibility of a mid century tipping point. Their modelling suggests 2050 would be the approximate start date of a slow but unstoppable and irreversible decline in the climate regulation provided by the AMOC.

The main driver of AMOC slow down is freshwater ice melting off the Greenland ice sheet making seawater less salty. Like sand thrown into a well oiled engine. Prof Jason Box @climate_ice showed me how the official models don’t capture how quickly that ice is melting.

There is huge uncertainty about what AMOC shutdown means for Ireland. We won’t necessarily become Newfoundland. Atlantic cooling may be countered by global heating. But if these tipping point projections are right, it moves Ireland from climate sanctuary to the frontline.

Increased storms, precipitation, river floods, weather whiplashes, constriction of growing seasons. Beyond that - as this mesmerising visualisation by NASA shows - shutdown of AMOC would have global consequences

The latest study supporting a mid century tipping point for the AMOC is, as I said, a pre-print. Not yet published in a journal, subject to changes after peer review. But a wise country would be throwing resources at further research on this. Paper 👉

Meanwhile, Ireland does not want a cap on flight numbers in Dublin airport, agriculture refuses to adopt a transition to net zero, ICE car usage continues unabated and only a modest reduction in CO2 emissions has been achieved.

You better book another 1st class all expenses round the world trip to tell us more about it 👍