Subtitles section Play video Print subtitles This video was made possible by Brilliant. The first 755 people to sign up over at Brilliant.org/reallifelore, will get 20% off their premium subscriptions. There are millions of lakes in the world and Canada is home to over 60% of them. Fortunately for Canadians though, none of these lakes are anywhere near as bad as the most dangerous one in the world which is actually located here in Africa, between the Democratic Republic of the Congo and Rwanda. This is Lake Kivu, and if you look at pictures of it on Google it doesn't really look all that dangerous, so what gives? It's kind of a big lake I guess. It's the 9th deepest lake in the world too, but that means that there is 8 more that are even deeper. There's other lakes like this one, that's literally called Boiling Lake, because the temperature can get up to 92 degrees Celsius. So what makes the innocent-looking Lake Kivu so dangerous? It probably has something to do with the fact that the lake seems to occasionally explode and kill everything around it. But how does that happen? A lake exploding sounds pretty weird, but it's because it doesn't happen very often. The first time in recorded history that we observed something like this was just back in 1984 at another African lake here, Lake Manoun. On August 15th of that year, local people reported hearing a loud noise and seeing a gas cloud emanating from the lake. 37 people ended up dying with reports of skin discoloration, which lead to investigators to initially believe that the incident was a terrorist attack. But, two years later, the nearby Lake Nyos experienced a very similar, but even more catastrophic event. Here's what really happened in both cases: The lakes were completely saturated with gases, like CO2, the CO2 may have come from volcanic gas below the lakes, or from the decreased composition of organic materials. But the end result of a high concentration of the gas in the water is the same. Before the lake becomes saturated though, it behaves much like an unopened soft drink. Meaning that the CO2 is dissolved in the water. In both the lake and the soft drink, CO2 dissolves much more readily at higher pressure. This is why bubbles in a can of soda form only after the can is opened, the pressure is released and so the CO2 comes out of solution. In the case of lakes, the bottom experiences way higher pressure than the surface, the deeper it is, the higher the pressure at the bottom is. This means that huge amounts of CO2 can be dissolved in large, deep lakes, like both of these were. CO2 also dissolves much more readily in cooler water, like at the bottom of a lake. So once a lake is saturated with CO2 like this, it becomes extremely unstable, all it takes is a trigger event, like a volcano, earthquake or explosion to set the whole thing off. Whatever the cause, the trigger event pushes the saturated water higher into the lake, where the low pressure can't keep the CO2 contained anymore. Bubbles start forming at the surface, a column of gas erupts on top, the water at the bottom is pulled up by suction which causes a runaway loss of CO2 and an eventual explosion. Imagine shaking a can of soda and opening it, but on an epicly bigger scale. At Lake Nyos, this event happened in the middle of the night and sent a 25 meter high tsunami surging into the other side of the beach, the lake turned a deep red and a 1.2 cubic kilometer toxic gas cloud of CO2 started migrating off the water and into the nearby villages. Because CO2 is denser than air, it has a bad tendency to stick to the ground while pushing breathable air up, as a result, when the cloud entered the surrounding villages, people couldn't breathe and experienced severe CO2 poisoning. Nearly everyone around the lake that night died and people as far away as 25 kilometers even suffered from it. In all, over 1700 people lost their lives in the catastrophe, as well as thousands of cattle and wild animals. But as bad as all of that was, the potential for the same thing happening at Lake Kivu would be a lot worse. These lake explosions are called Limnic Eruptions, and Lake Kivu has the exact same symptoms that the previous two lakes had, the only differences are that Lake Kivu is a lot bigger and has a lot more gas built up inside of it. 65 cubic kilometers of methane and 256 cubic kilometers of CO2, 2 million people live around the shores of the lake and if an eruption were to happen here, all of their lives would be in jeopardy. Even creepier though, geologists operating around the lake discovered evidence that suggested a local extinction event happens about once every 1000 years that wipes out a large part of the local wildlife. If it's the lake exploding once every thousand years like it seems, well, that's pretty bad news. So what are we doing to fix this problem? Not really anything at all right now, the Rwandan government extracts a lot of methane from it for energy purposes, when it's probably not enough to guarantee that the disaster won't ever happen. At the first two lakes I talked about, they've installed a series of pipes to release the gas above the surface, but since Lake Kivu is so much bigger that may not be as practical. Releasing that much gas would be 2% of the annual amount humanity releases from burning fossil fuels and it would cost millions of dollars to do, which the neighboring countries may not be so willing to spend. The solution to the most dangerous lake in the world remains elusive and with no clear answer and sight it may only be a matter of time until another disaster happens. If you want to be the one to come up with the answer you can mention it in the comments, but before you do, you should probably learn a bit about physics and chemistry by visiting the courses over at Brilliant.org. Brilliant is the best place to learn about things like everyday physics, special relativity, computer science and more because they teach you how to understand things visually without making you check for pointless rules. With Brilliant you learn by playing through puzzles that help you build you core knowledge and intuition so you can actually come to learn about these concepts. You can take as many of these masterfully designed courses as you want with their premium subscription which, by being one of the first 755 people to click on the link in the description, you can get for 20% off. You can learn something cool and support RealLifeLore at the same time and I'll see you again next Friday for another brand new video then.