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  • 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.

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  • 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.

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