What Is COP21 and Why Does it Matter?

The logo of the upcoming COP21 Climate Conference is seen at the Elysee Palace during a meeting with African Leaders in Paris
The logo of the upcoming COP21 Climate Conference is seen at the Elysee Palace during a meeting with African Leaders in Paris, France, Tuesday, Nov. 10, 2015. The eleventh session of the Conference of the Parties serving as the meeting of the Parties to the Kyoto Protocol (CMP 11) will take place from Monday, 30 November to Friday, 11 December 2015 in Paris, France. (AP Photo/Francois Mori)

"COP21" is shorthand for "Conference of the Parties 21," which tells you absolutely nothing. You could call it the "2015 United Nations Climate Change Conference," but that gives you little more than a vague outline of what it is. In truth, COP21 is a fairly simple concept and can be explained like so: Countries from all over the world are going to meet up in Paris at the end of this month and try to decide the best way to keep the world from getting any hotter.

When you put it that way, it doesn't sound so bad. In fact, the delegates are only going to try and keep the planet from warming more than two degrees by the end of this century. The best and brightest policymakers from the United Nations and all they have to worry about is two lousy degrees in 85 years? Piece of cake, right?

Sure, if the cake was made of terrifying consequences.

Why Two Degrees Makes All the Difference

What would happen if the world got just two degrees warmer? Doesn't sound like a lot, does it? Walk outside when it's 24℃ (75℉) and it won't feel much different than when it's 22℃ (71.6℉). But the problem with that analogy is that it's extremely localized. Two degrees really doesn't make much of a difference when you're standing on your front doorstep. That's the kind of weather that happens every day. But what if the warming wasn't localized? What if it was everywhere?

Think about this: The surface area of your average doorstep is less than one square meter. The surface area of the Earth is 510 billion times bigger than that. So what would it take to warm the whole planet 2℃? A lot more heat than any Earthling would enjoy.

Here's the really scary part: Humans have never lived on a planet that's two degrees warmer than it was before the Industrial Revolution. According to NASA's Earth Observatory, the planet is about 0.8℃ warmer now than it was in 1880. Some variation in the planet's temperature is natural over time, but two-thirds of that increase has taken place in just the last 40 years. Why is that?

Well, ever since we started burning fossil fuels like coal and oil, we've added more carbon into Earth's atmosphere than it would naturally receive, such as from wildfires and the occasional volcanic eruption. And when there's more carbon in the atmosphere, the atmosphere traps more thermal energy from the sun. In other words, the more gas we pump into the atmosphere, the hotter we make the planet. It takes a lot of pumping to warm the planet, but we've been doing it for a long time.

And here's the thing about the planet: It is a very complicated machine. Warm a living room by two degrees and it's relatively unchanged, warm a 510 billion square meter sphere teeming with oceans, weather systems and ecosystems by two degrees and the impact is almost incalculable. There are, however, a few things we can expect:

Also, according to a recent study, climate change is terrible for your sex life, but that's none of my business.

How can two degrees of warming cause so much damage? Because it's doubling down on the laundry list of disasters we've already experienced with less than one degree of warming. Remember, the global average temperature has risen 0.8℃ since records began in 1880. As NASA explains, the amount of energy required to do that can literally change the face of the Earth. "A one-degree global change is significant because it takes a vast amount of heat to warm all the oceans, atmosphere, and land by that much," the agency writes. "In the past, a one- to two-degree drop was all it took to plunge the Earth into the Little Ice Age. A five-degree drop was enough to bury a large part of North America under a towering mass of ice 20,000 years ago."

That's what happened when the temperature dropped. We have no conception of how bad things will get if it rises. "If we start warming the planet way beyond what humans have ever experienced, God knows what will wait for us," Carlo Jaeger, the chair of the Global Climate Forum, told CNN in May.

And that, in a nutshell, is why COP21 matters.