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Weakest Gulf Stream in 1,000 years
could bring more ‘extreme’ winters to
UK and Europe, says study
Scientists say there has been a dramatic slowdown
in the flow of ocean currents that play a vital part
in the world’s climate.
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The Gulf Stream that helps warm the UK and
northwest Europe is at its weakest in over 1,000
years and could lead to more “extreme and intense”
winters, according to researchers. They
say the slowdown observed in the 20th century
is “unprecedented” and likely connected to
climate change.
The Gulf Stream is part of a larger “conveyer belt”
of ocean currents known as Atlantic Meridional
Overturning Circulation (AMOC) and carries warm
water from the tip of Florida towards Europe.
Its effect ensures Britain has relatively mild
winters and without it experts believe temperatures
would be around 5C cooler. AMOC helps
ensure the oceans are continually mixed, with
the heat and energy distributed around the
globe and affecting the climate.
Scientists say it was relatively stable until a
decline around 1850, followed by a more drastic
dip in the mid-20th century. The change
could bring “more extreme and intense winter
weather events in Europe”, a greater chance of
flooding on the US east coast, and also global
consequences, according to the study.
“A major mechanism for heat redistribution
and crucial to the world’s climate, an abrupt
slowdown of the AMOC could trigger disruptions
around the globe - including a sudden rise in
regional sea levels, changes in the position of
major rainfall and arid climate zones,” say the
research team.
The international study, which included experts
from University College London, as well as Ireland
and Germany, reconstructed the flow of AMOC
over the last 1,600 years.
They used indicators such as proxy data from
tree rings, ice cores, ocean sediments and corals,
as well as historical data such as ship logs.
UCL’s Dr David Thornalley, who co-authored the
study, said a slowdown in AMOC due to global
warming had long been predicted but that it
was “increasing evidence in support of the modern
Atlantic Ocean undergoing unprecedented
changes in comparison to the last millennium”.
He said marine ecosystems were already being
affected. The potential flood threat to the US
could come as the northward flow of AMOC,
which deflects water away from the east coast,
is disrupted
“As the current slows down, this effect weakens
and more water can pile up at the US east coast,
leading to an enhanced sea level rise,” said
lead author Dr Levke Caesar, from the ICARUS
Climate Research Centre and Ireland’s Maynooth
University.
Climate modelling also suggests global warming
could weaken the Gulf Stream by another
34-45% by 2100, according to researchers - who
warn it could be a “tipping point at which the
flow becomes unstable”.
The study is published in the journal Nature
Geoscience .
Braemar in Aberdeenshire
this month recorded
-23C, the lowest UK
temperature in 25 years