Could the Gulf Stream Collapse? | The Agenda

Importance of the Gulf Stream

In this section, experts discuss the importance of the Gulf Stream for our climate and weather.

The Role of Heat Transport

• The Gulf Stream is one of the ocean's main ways of transporting heat from lower latitudes up to higher latitudes.

• The role of heat transport is to spread some of that heat out and let the climate at more northerly latitudes be a lot warmer than they would otherwise be.

• It makes wide swaths of northern Europe much more habitable than they would be if in fact, the Gulf Stream wasn't transporting that heat northwards.

Understanding the Significance

• Anyone who has visited Northern Scotland and then gone to Labrador can see how important it is.

• Our general perception is that the Gulf Stream is a persistent feature of the ocean and unlikely to change.

• However, it may not be as reliable as we had thought.

Atlantic Meridional Overturning Circulation (AMOC)

In this section, experts discuss AMOC and its relationship with the Gulf Stream.

What is AMOC?

• AMOC stands for Atlantic Meridional Overturning Circulation.

• It describes how cold water sinks underneath warm water in order to balance out all that warm water being pushed towards higher latitudes by things like the Gulf Stream.

Relationship with Gulf Stream

• The Gulf Stream is just one part of that circulation.

• If we're pushing a bunch of warm water to the pole, then either the poles are getting filled up with water or there's some return flow somewhere else.

• The cold water that sinks underneath the warm water in AMOC is what drives that return flow.

Potential Disruption of Gulf Stream

In this section, experts discuss the potential disruption of the Gulf Stream and its implications.

Possibility of Disruption

• There is a possibility that climate change could lead to a disruption of the Gulf Stream.

• If it were to happen, it would have significant implications for our climate and weather patterns.

Implications

• It could cause temperatures in Europe to drop by several degrees Celsius.

• It could also lead to more extreme weather events like storms and droughts.

The Importance of the Gulf Stream

Kent Moore, a professor of physics at the University of Toronto, explains how the climate control system works and why it is important. He also introduces an animation from NASA that shows how warm water moves northward and cold water moves southward.

The Gulf Stream and Climate Control

• Warm water moving northwards loses heat and moisture to the atmosphere, becomes dense, and sinks in a process called convection.

• Lots of heat and moisture at high northern latitudes are crucial for climate control.

• Disruption of the Gulf Stream could weaken or shift southwards, causing problems for those living in the atmosphere.

Comprehending the Vastness of the Gulf Stream

Stephanie Waterman, a physical oceanographer at Dalhousie University, discusses how difficult it is to comprehend the vastness and scale of the Gulf Stream.

The Scale of the Gulf Stream

• The width of this stream can be up to 100 kilometers wide and extend through 4,000 meters tall.

• The transport volume is measured in millions of meters cubed per second which is equivalent to about 750,000 100-kilometer soldiers marching by every minute.

• This current takes a thousand years for water to complete one cycle.

Understanding Ocean Circulation System

Brad de Young, a professor emeritus at Memorial University's Department of Physics and Physical Oceanography explains what happened during previous ice ages due to changes in ocean circulation systems.

Ocean Circulation System During Previous Ice Ages

• During the previous ice age, the Gulf Stream weakened and shifted southwards, causing Europe to become much colder.

• The ocean circulation system is a slow-moving current that takes a thousand years for water to complete one cycle.

• Changes in the ocean circulation system can have significant impacts on climate.

The Younger Dryas Event

This section discusses the Younger Dryas event, which occurred about 12,000 years ago and lasted for approximately 1,000 years. It caused a sudden cooling in Europe and disrupted weather patterns in the Northern Hemisphere.

Cooling in Europe

• The Younger Dryas event caused a sudden cooling in Europe that lasted for approximately 1,000 years.

• Temperatures in Europe dropped by about 10°C during this period.

• Freshwater influx made it harder for water to sink, which reduced heat transport northwards.

Disrupted Weather Patterns

• If the Gulf Stream weakens or collapses, weather patterns in the Northern Hemisphere would be significantly disrupted.

• Storm patterns would change hugely and ice conditions in the Northern Atlantic would all look very different.

• Even small amounts of freshwater could lead to significant changes.

Could the Gulf Stream Collapse?

This section explores whether the Gulf Stream could collapse and what that might mean for ocean and atmospheric circulation.

Potential Collapse

• Niklas Boers warns of "early warning signs for a potential collapse."

• A spectrum of things could happen if heat transport from equator to pole shuts down or slows down significantly.

Knock-On Effects

• Knock-on effects on ocean and atmospheric circulation would be complex and interconnected.

Concerns about a potential slowdown in the Gulf Stream

The speaker discusses concerns about a potential slowdown in the Gulf Stream and its impact on climate change.

Potential Slowdown of the Gulf Stream

• There is a possibility of a slowdown in the Gulf Stream within the next century, leading to incremental cooling in Northern Europe and changes to ocean circulation across the globe.

• A slowdown would have knock-on effects, but not as dramatic as if it were to collapse.

• The climate system is non-linear, so it's possible to have transient events where periods of warming are followed by deep freezes.

• There is concern that we may be reaching a tipping point where there are two states for the Gulf Stream: very active or less active.

Impact on Canada

• If such circumstances occur, it would dramatically influence Atlantic Canada with major disruptions to temperature and conditions affecting fish stocks and shipping.

• It would shift agricultural activity across Canada and change precipitation patterns hugely. This would be a major disruption of weather that would look nothing like it has looked in the last hundred years.

Controlling Climate Change

• While slowing down or cooling portions of the planet might appear appropriate, it could utterly disrupt the whole climate system within which we operate with unhappy consequences for lots of people.

• We cannot control or control the temperature of Earth like we do our house with a thermostat because there are lots of unintended results from doing so.

Overall, there is concern about a potential slowdown in the Gulf Stream due to its impact on climate change. Such an event could lead to incremental cooling in Northern Europe and changes to ocean circulation across the globe. If such circumstances occur, it would dramatically influence Atlantic Canada with major disruptions to temperature and conditions affecting fish stocks and shipping. It would shift agricultural activity across Canada and change precipitation patterns hugely. While slowing down or cooling portions of the planet might appear appropriate, it could utterly disrupt the whole climate system within which we operate with unhappy consequences for lots of people.

Climate Change and Tipping Points

In this section, the speakers discuss the complexity of climate change and how it is interconnected with various systems. They also talk about tipping points and how they can lead to sudden changes in the climate system.

The Complexity of Climate Change

• Climate change is complicated, complex, vast, and interconnected in ways that we don't fully understand.

• There are knock-on effects of actions that we don't fully comprehend.

• Geoengineering tools are crude, and we don't understand the complexity of their response.

Tipping Points

• Climate change is mostly linear, but there can be knock-on effects where a big transition occurs suddenly.

• Tipping points happen because the climate system is highly nonlinear.

• Losing Arctic sea ice or land glaciers would have dramatic transitions.

• The Gulf Stream is probably the most dramatic tipping point example.

Containment Strategies

• Throwing a net over a weakened Gulf Stream system would not be feasible.

• Geoengineering responses to these problems have not looked more appealing than the problems themselves.

Conclusion

• There isn't an absolute point where we need to worry about tipping points; they could happen somewhere along the line from where we are now to those 1.5 or 2° temperature changes.

Geoengineering Solutions

In this section, the speakers discuss geoengineering solutions to climate change and their feasibility.

Feasibility of Geoengineering Solutions

• The tipping points for climate change are not far away, and scientists are uncertain about how close they are.

• There is no geoengineering solution that has been deemed feasible or tested. Scientists have concerns about the knock-on effects of perturbing the system.

• Diverting attention from reducing carbon emissions to geoengineering solutions is a concern. All proposed solutions have unanticipated consequences, and humans have a history of messing things up.

Final Thoughts

• The speakers agree that poking the bear (i.e., implementing geoengineering solutions) is not advisable.

• They conclude that getting carbon emissions under control is the only way to contain warming and prevent reaching tipping points.

Speaker's Last Name

In this section, Steve notes Stephanie Waterman's last name as being fitting for her work in earth, ocean, and atmospheric sciences.

Stephanie Waterman's Last Name

• Steve notes that Stephanie Waterman has the perfect last name for her work in earth, ocean, and atmospheric sciences.