8 Ways Climate Change Isn't Messing Around

4. Thermohaline Circulation

Heyoo, this is a big one.

So there's this thing called thermohaline circulation which is basically a big mixing pot for the world's oceans and atmosphere. It a bit like when you swoosh all the water around in the bath to mix up the hot and cold.

It is driven by differences in seawater density. When sea ice forms it expels salt, making the supercooled water around it dense, so it takes a dive and kicks off a big old global current system around the planet. This process is responsible for not only distributing heat around the Earth, but also filling the deepest, darkest reaches of the ocean with lots of lovely oxygen.

In the past, when CO2 levels hike to about 0.1% (we're currently on 0.04%) in the atmosphere, thermohaline circulation grinds to a halt which is super-duper bad news for literally everything, oh god.

If this were to happen again there be huge localised shifts in temperature, amongst other things, turning the UK into a winter wonderland. Basically all of the weather everywhere would change and, as we've discussed, this is a pant-sh*ttingly bad thing. We're not even sure exactly what would happen because our current weather models just give the hell up when you try to stop thermohaline circulation.

Not only does the weather go loopy-lou, but the delivery of oxygen to the deep ocean would stop. This would mean that basically every part of the ocean that can't be frothed up by a gentle breeze would become an obsidian mass of oxygenless, lifeless darkness. Anything that doesn't spend its life basking in the shallows would die and the only thing that would flourish would be anaerobic bacteria.

Oh yeah, did I mention that anaerobic bacteria is a whole other level of nope?

These little guys like to produce something called hydrogen sulfide, a gas famous for its distinctive and pungent rotten-egg aroma. The reason it smells so bad to us is because it also happens to be really, properly toxic. Turning the ocean into a giant, stagnant pool of rotten eggs would cause everything on the coast to die and necessitate the need for a stylish gas mask for a day at the beach.