Climate scientists have reported signs of an imminent collapse of the Gulf Stream. Warning signs include the weakening of the North Atlantic ocean currents, being at their slowest in at least 1,600 years. But what does the Gulf Stream Collapse mean for the world’s climate? First, let’s find out what the Gulf Stream is and what it does.
What Is The Gulf Stream?
Ocean currents are very complex, but always follow patterns as currents travel around the world. The Gulf Stream, part of this pattern, is a strong ocean current that flows from the Gulf of Mexico in to the North Atlantic.
The map below shows the Gulf Stream’s path, as it carries warm water up the east coast of North America, and then on towards Europe. The UK is directly in the path of the Gulf Stream’s warm currents.
How Does The Gulf Stream Work?
Cold air from the Arctic cools water at the surface of the North Atlantic. As the surface water cools, sea ice begins to form. The ice pushes salt out of the water as it freezes, making the surrounding water more salty. The saltier and colder the water is, the more dense it becomes. This dense, salty water at the ocean’s surface sinks down to the ocean floor. It starts to flow south, very deep below the surface of the ocean.
Because water is sinking and flowing away from the North Atlantic, a current forms at the surface pulling water in to the North Atlantic. This current is the Gulf Stream, replacing the cold water with warmer water flowing from the Gulf of Mexico.
The circular pattern of currents flowing around the Atlantic is called the Atlantic Meridional Overturning Circulation (AMOC).
How Does The Gulf Stream Affect Us?
The Gulf Stream has a large influence over the climate of the UK, as well as North America and most of Europe. Winter temperatures in the UK are warmer than other places with similar latitudes (e.g. Canada) because of the Gulf Stream. Scientists estimate that the Gulf Stream makes UK winters at least 5oC warmer than they would be without it. It’s not just the UK climate that is warmed by the Gulf Stream though. The east coast of the USA and Canada, and most of Europe are also warmed by the Gulf Stream by varying degrees. The stable flow of the Gulf Stream helps to stabilise weather patterns around the northern hemisphere.
Will The Gulf Stream Collapse?
The AMOC (and therefore, the Gulf Stream) relies on water cooling and becoming saltier in the North Atlantic. As the world’s climate is becoming warmer, this is happening less and less. Ice sheets are melting, adding fresh water to the sea, and less sea ice is forming. Therefore, the water in the North Atlantic is not becoming as salty. The current relies on the dense, salty water sinking, and so with this happening less, the currents slow.
Scientists studying data obtained from ice cores have shown that the AMOC has had two states: fast and slow. The Gulf Stream has been in it’s fast state, but it may be gradually transitioning to its slow state. The Gulf Stream probably won’t completely stop, but it is very likely to rapidly slow down. Scientists don’t know when this Gulf Stream collapse will happen, but it is likely to be within decades. In the slow state, the Gulf Stream will bring little warmth from the Gulf of Mexico to the North Atlantic.
Is There Going To Be Another Ice Age?
The Day After Tomorrow is an apocalyptic movie based on the collapse of the AMOC. In the movie, the AMOC collapses very quickly, leading to a new ice age starting almost overnight. Although some of the ideas in the movie are correct, the timeline and severity are exaggerated (although it’s definitely worth watching anyway!).
The Gulf Stream collapse is actually a gradual slowing down of the AMOC. Data shows that the currents have been slowing down for around 200 years. The slowing down of the currents has been happening much more quickly over the last 50 years.
We will not have an overnight climate change because of the Gulf Stream collapse. Instead, we can expect to see the effects gradually developing over the next decade or two, with the reduction in the Gulf Stream leading to lower temperatures in the UK. This however will be combined with a warming global climate, and so the future will not be a slightly cooler version of the current climate.
What Will The Future UK Climate Be Like?
The earth’s climate is very complex, and changes are difficult to predict. The climate is changing, and in general it is warming (see our article on climate change). At the same time as the earth’s climate is warming, the Gulf Stream collapse could reduce temperatures in Europe by several degrees. It is possible that the average temperatures in the UK will reduce by around 8oC.
The warming global climate and the collapse of the Gulf Stream will offset each other to some extent in the UK. Over the next few decades, if the Gulf Stream does not collapse, the UK climate will become significantly warmer. We can expect the climate in the UK to become similar to the current Mediterranean climate. However, if the Gulf Stream does collapse however, this will cool the UK climate significantly.
Taking into account the changing global climate and the Gulf Stream collapse, the UK will probably have colder winters, with temperatures averaging approximately 0oC. It’s likely that winters will be snowy and icy. There will generally be less precipitation, with summers being much dryer than they are now. Summers may be warmer than they are now due to the warming of the world’s climate. The weather patterns will become less stable, with more frequent storms coming in from the Atlantic.
These changes to the UK climate will have a major impact on growing crops in the UK. The growing season will be shorter due to the colder winters. The lower rainfall will reduce the amount of arable land that does not need irrigation. A lack of rainfall will also make irrigation more difficult as there may not be enough excess water.
What About The World Climate?
The Gulf Stream has a major effect on the world’s climate. It distributes warmth around the North Atlantic and beyond. With the collapse of the Gulf Stream, the entire northern hemisphere will be cooler. Winter weather will be more severe in Europe and North America, with lower temperatures and more ice and snow. Europe will be much dryer. Weather patterns around the world will become much less stable and unpredictable.
Climate change will have a huge impact on the world, with hotter and dryer weather in many parts of the world. The temperatures in the northern hemisphere north of the tropics may be reduced by the collapse of the Gulf Stream. This will not, however, help the regions of the earth in the tropics. Large parts of the world will become uninhabitable due to climate change, leading to mass migrations and further strain on the habitable parts of the world. Read more about the global effects in our article on climate change.
Can We Stop The Gulf Stream Collapse?
The Gulf Stream collapse is primarily driven by climate change, itself accelerated by carbon emissions. The warming climate means warmer temperatures in the North Atlantic, and therefore less sea ice. The waters of the North Atlantic do not become as salty, and warmer water will remain on the surface stopping the flow of the AMOC.
Scientists do not know how much warming of the climate it will take for the AMOC to collapse completely. The only chance that we have of preventing the collapse is a significant and rapid reduction in carbon emissions. Reducing carbon emissions helps to reduce global climate change, which in turn will help maintain the stability of the Gulf Stream.
How Can I Prepare For The Gulf Stream Collapse?
As the world climate becomes more and more difficult to predict, the most important thing is to ensure that we can still grow food. We don’t know for certain if the Gulf Stream will collapse, or just slow down. We do know that global temperatures are going to increase, and the climate is going to become dryer. However we don’t know for certain whether temperature changes caused by the Gulf Stream collapse will mean an overall reduction or increase in temperatures in the northern hemisphere.
Crops that we grow need to be able to tolerate a wide variety of climates so they are tolerant of our future climate. We should plan now to grow fruit trees and vegetable crops that will be suitable to a warmer, dryer climate, and others that will be suitable to a cold climate. This will mean that whatever happens, we will still have the ability to grow food and survive.
What do you think we can do to prepare for the climate of the future? Let us know in the comments section below.