Are we聽weakening an ocean current that is crucial to the global climate? It鈥檚 a vital question we may soon struggle to answer due to a funding crisis.
For the past 15 years UK and US researchers have used a string of moorings, running from the Bahamas across the Atlantic to the African coast, to detect a weakening in the Atlantic conveyor belt.
A heavily dramatised version of the slowing of the Atlantic meridional overturning circulation (AMOC) played out in The Day After Tomorrow, in which the current鈥檚 collapse flipped the US into extreme cold.
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The extremes of the 2004 film bear little resemblance to the science, but the AMOC weakening could have real, major socio-economic effects.
The current moves heat northwards up the Atlantic, so a slowing could lead to cooler temperatures in north-west Europe, significantly affect sea level rises on the US eastern seaboard, and could shift rainfall patterns in Africa.
The UK-led scheme monitoring temperature, salinity and current velocities from near the Atlantic鈥檚 surface to the sea floor, known as as , has been in the water since 2004.
The array鈥檚 funding has always been renewed in the past but will expire in 2020. A review in January recommended continuing backing it. But researchers have been unable to secure a green light for the 拢1 million-a-year needed from the body which decides, the Natural Environment Research Council (NERC).
Finding out whether the weakening of the AMOC is driven by artificial global warming or a natural cycle needs 20-40 years of observations, so stopping now would leave that question unanswered. Researchers say the need around a further decade of data. Climate models .
Meric Srokosz of Southampton University says: 鈥淚f we continue observing, we will be able to see whether the IPCC [the UN climate science panel] projections of AMOC decline are happening or not, but the record is not long enough to say definitively [yet].鈥�
Jon Robson of Reading University fears losing 鈥渃rucial observations鈥� which would limit the ability to make future predictions of the North Atlantic. 鈥淎t the moment, we do not know whether this weakening is part of a natural cycle, or some longer-term shift caused by human changes.鈥�
NERC said it was considering options for future funding.
