What happens if a crucial ocean current collapses? | About That

foreign that's a clip from the movie The Day After Tomorrow and in that film surging sea water levels giant tidal waves and a sudden Ice Age were all caused by the collapse of one pivotal force in ocean current the current depends upon a delicate balance of salt and fresh water we all know that yes but no one is taken into account how much fresh water has been dumped into the ocean because of melting Polar Ice I think we've hit a critical desalinization point the ocean current they're talking about there is the Meridian Al massive and it's responsible for circulating the water in the Atlantic Ocean and maintaining weather patterns and experts they're worried it might be weakening and that the window to act might be narrowing well scientists are warning that's a crucial Tipping Point could be reached in just two years time they would see the start of the collapse of the Atlantic Gulf Stream if Global emissions aren't reduced so here's a little primer on that amok current I mentioned and how it works it starts at the North Pole mostly and where you have water becoming more dense because it's becoming cooler and Ice forms and then after many centuries um it slowly resurfaces and to close the cycle it takes water from where it's warmer the tropics and brings it back to the poles a new says the amok country and while 2100 might seem like a long way off the research does the collapse could happen in just two years from now 2025 though several scientists have said you know that's that's highly unlikely even if it's not totally clear yet when this could happen does it could be bad okay but skyscraper tells tsunamis and a mini Ice Age across North America within two days though like is that even accurate yeah it's hyperbole it's Hollywood to displace this amount of water I believe it would really take an object that is the size a few kilometers to displace this much water okay so luckily the day after tomorrow isn't exactly realistic but experts believe the amok has shut down before a long time ago like we're talking 12 13 000 years ago and the worry is if it's happened before it could happen again so what could that look like it's highly speculative but people believe northern Europe will cool down a little bit it might disrupt the rains so we might see crop failures the oxygen in the water my decrees which might in turn cause great harm to ecosystems see the ocean currents act kind of like a global thermostat the amok moves water from warmer tropical regions to cooler Arctic regions up north and I want to give you a visual of how it all works so I'm going to head outside for a little science experiment to explain that and why it's so important so we're just outside the CBC building and we don't exactly have an ocean to work with but we do have this and I'm going to use it to show you how the ocean currents circulate and this little mini water tank here believe it or not is going to be the Atlantic Ocean for us on this side we are going to pretend that this is the Arctic and then over here on this side that's where warm water is this is the tropics I have [Applause] some ice cubes here what I'm hoping is gonna happen here is because cold water is heavier and denser it's going to sink to the bottom okay so hopefully when I drop this in this is actually what's going to happen all right so here we go here goes nothing yeah exactly you can see the cold water sinking to the bottom I'll put another one in just so we can watch and you can see it going straight across that is where it's going to get warmed up by the Sun so over in the tropics we're going to have even warmer water coming in and it has red dye in it so that way you can see what happens when we add the warm water put in a little bit maybe a little more okay and you can see it I'll add an ice cube there yeah and it's starting to happen look the red water is starting to rise because it's warmer as the cold water moves across the tank and is really making this circular effect happen in this process like believe it or not it actually takes hundreds of years and there are a few like pretty incredible things that are happening in this process it's not just about moving water around but you know the water as it moves it distributes nutrients in the ocean so it's kind of like it's fertilizing it phosphorus the nitrogen they they feed Plankton which then goes on to feed other sea life and that goes all the way up the food chain so without these nutrients circulating you could potentially see ecosystems start to break down and an important thing here cold water actually holds more gas so it soaks up the CO2 and it really captures it and takes it down into deep Waters which is really important because it's keeping it out of the atmosphere and we know that that adds to global warming part of the reason why we're starting to see this process slow down in the first place and another thing that's really important about this process is that it really regulates temperature so it keeps the weather from becoming too severe but this process of circulation it's getting weaker and we could potentially see it stop entirely foreign [Music] we will release a lot of fresh water into the upper ocean of the North Atlantic it could collapse I could just stop the circulation ice melting in Greenland is a major factor in all of this the Greenland ice sheet is the largest ice mass in the Northern Hemisphere and scientists have been expressing alarm at the rapid rate of its mouth the CO2 emissions that we produce as humans like deforestation and burning fossil fuels they're major contributors to that melt nothing in the history of Earth has emitted so much CO2 as we have in the past decades in so such a short amount of time and like we heard In that clip from the movie earlier the current depends upon a delicate balance of salt and fresh water so if we think back to our experiment with the cold water when we add more fresh water it slows the cold salt water from sinking because it's lighter so when that water doesn't sink our conveyor belt the amok slows down and eventually stops working when you look at uh what's going on with food affordability around the world climate actually impacts food affordability every single day yeah the change in climate has a significant effect on what you pay for food severe weather flooding droughts it's all putting pressure on firms across North America cattle Farmers for example are thinning their herds in near record numbers because of years of unrelenting dry weather and now it's catching up to us as consumers and that's why the meat counters become but becoming more expensive and many crops have taken a beating too wheat and canola which we grow a lot of in Canada are susceptible canola can be sensitive to its environment it needs moisture to grow but not too much water or it'll die you have to put a lot of money in the ground to increase yields and if yields are there due to Mother Nature's wrath that becomes problematic for Farmers so it gets more expensive to grow these crops right and the severe weather that's predicted if amok collapses it's likely going to cost us all a lot more just to eat but as I mentioned earlier we're not at this point yet [Music] in this worst case scenario um Reckless teenager uh Humanity we could potentially collapse the emark before 2100. that's the worst case scenario without any action there is work underway at the international level the 2015 Paris agreement and climate Accords that have followed are working on a solution to decrease CO2 emissions one of which is to limit the global temperature increase to one and a half degrees Celsius above pre-industrial levels but we know from a recent World Meteorological organization report that there isn't two in three chance we'll cross that threshold as for the amoc research shows it is likely to keep on slowing down and although 2100 seems like a long way off the sign suggests we need more intervention now if you cross a Tipping Point you cannot come back easily um it's it's really like falling off a cliff you can climb back up the cliff but it will be a lot longer than falling from the cliff

Channel: CBC News

Views: 32,509

Keywords: Ocean current, AMOC, current, climate change, weather, atlantic ocean, climate, about that, andrew chang, cbc, cbc news, cbc explore, exploreapp

Id: 3ComkHfHyBM

Length: 10min 6sec (606 seconds)

Published: Thu Aug 03 2023