Could changing ocean currents make UK winters colder?
ITV News Science Correspondent Martin Stew speaks to researchers about the ocean's currents, and what this could mean for the climate
On board one of the UK's most high-tech floating laboratories, scientists work day and night to help map the movement of water in the ocean to better understand global warming.
The RRS James Cook spends around 260 days a year travelling around the globe carrying out different scientific expeditions. This includes monitoring changes in ocean currents, which have a big impact on our climate.
ITV News was given rare access to the vessel to learn about one of the ship's biggest expeditions, RAPID.
The project looks for changes in the Atlantic Meridional Overturning Circulation (AMOC) - the ocean current which includes the Gulf Stream and helps regulate UK temperatures.
What is AMOC?
The Atlantic Meridional Overturning Circulation (AMOC) is a large system of ocean currents, like a conveyor belt, that circulates water within the Atlantic Ocean.
It is driven by differences in temperature and salt content - the water's density - and is critical in regulating the climate in Europe.
The mild winters experienced in the UK and north-western Europe are partly due to the AMOC bringing warm water north and cold water south.
These currents explain why the weather in this country is milder than you'd expect. In terms of latitude, we are as far north as Canada and yet our winters aren't as cold.
This is because we are blanketed in warmer water, which started in the Caribbean and headed towards us in the Gulf Stream - an important part of the AMOC system.
Oceanographers have been measuring the AMOC continuously since 2004, using ships like the James Cook. And as our atmosphere warms, climate models predict the flows could change.
Dr Ben Moat, a physical oceanographer at the National Oceanography Centre, told ITV News the models "suggest that as the ocean circulation starts to slow down, the temperatures in the Northern Hemisphere will reduce".
"But this is still in a warming planet," he added.
Dr Moat has been involved in the RAPID project for 12 years. He explained that 71% of the planet's surface is water, and it is connected to the atmosphere.
"We have to understand how our oceans are changing," he said.
"Ocean currents themselves transport vast amounts of heat, carbon and nutrients around the planet, so any changes to them caused by the human-induced changes that we see, are really important for impacts on the climate, but also for society."
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Asked about what a change in the flow of the ocean currents could mean for the UK climate, Dr Moat said: "They [the models] are predicting that this circulation will weaken into the future, so that will imply that we will get cooler temperatures on average around Europe and the UK."
The RAPID project has collated 20 years of data so far, but Dr Moat says that several more years of observations are needed to develop a greater understanding.
Researchers onboard the vessel use different scientific instruments, such as the CTD - which stands for Conductivity, Temperature, and Depth - to take measurements of the ocean.
Sunke Trace-Kleeberg is a postdoctoral researcher at Southampton University who joined the project earlier this year.
She told ITV News that using this equipment enables them to take water samples from different depths of the ocean and bring them back to the surface.
"We can lower it 5km underneath the surface to see what's going on at each different level," she explained.
In a world where climate science is often contested, the scientists on board the James Cook hope data can anchor our understanding of exactly what's going on.
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