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Throughout this video I say "probability curve" when a statistician would say "probability distribution." I just want to say that I'm aware of this, and that it's a choice I intentionally made because I felt like it made it easier to understand.

While I would very much like to get deep into probability functions, what they mean, and how they work, I don't know if that's necessary to understand the world with curves. And this isn't just about climate and weather, pretty much everything is better understood if it's understood in terms of probability functions. And I generally like to see the world not for the collapsed reality dot, but for the function underneath. It's why winning at gambling always feels empty to me, I know that the underlying function has my losing even if happened to get lucky. So, in a way, gambling is always losing, even if you win.

I know I'm an armchair statistician, and that lots of people will be annoyed by the language in this video, but I hope you can forgive me!

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Good morning, John.

Give me four minutes so that we can have a legit conversation about a warmer Earth and what that means for actual weather: the kind of conversation that we never get to have because it doesn't fit into a 15-second soundbite.

Here's what we all need to get (and I don't think it's anybody's fault for not getting this): when we talk about the effect that a warmer Earth will have on the weather, we're not talking about what's gonna happen, we're talking about what's *probably* gonna happen, or more properly, the probability of what will happen.

We are never gonna know how many big storms are gonna hit the U.S. in any given hurricane season. But we can take a look over the last 50 years and see how many major storms formed per year, and I'm doing that right now.

I'm putting a dot for every year. Most of the years had two storms, some have had five, some have had four, some have had zero. That year with seven storms there, that was 2005, the year that Hurricane Katrina hit New Orleans.

Alright, yeah you see what happened here. There is a curve. This is a probability distribution and it is always how we should be thinking about how a changing climate is affecting weather today, now, this year.

Not the dots, the curve. Every year at the end of the hurricane season this probability curve collapses into just another dot. It is no longer a set of things that could happen; it becomes a very specific thing that did happen.

Last year it collapsed into four major storms. The year before that, two. The year before that, two again. And the year before that, zero! Oh! Do we have a-- Do we have a trend happening here? No, no, NO!!! This is not a trend!

Every year the curve runs itself again and it might collapse down to zero, or it might collapse out to seven. Like, look at the dots. Obviously no one dot on this curve is important, and also the curve is saying that all of this stuff happens. Everything that's in here is well inside the realm of normality.

The number of serious storms from year to year can jump while being the effect of the same probability curve. A warmer planet doesn't take you from this to this because global energy in the system isn't the only important variable. It takes you from this... to this. Something important is changing, and that's shifting the curve.

When that new curve collapses into its reality dot that might still be at zero, it's just less likely than it used to be. And years like 2005 will still be rare, they will just be less rare. And if there are more strong storms, there's a higher likelihood that they'll end up hitting in the worst places possible as Harvey did, as Katrina did.

Homes that used to be considered safe might now find it difficult to get insurance because no one understands probability curves like the people who work at insurance companies. And these probability curves are what we use to determine whether a flood has like a 1 in 100 chance of happening or a 1 in 50 chance of happening.

And as that changes, those "hundred-year floods" start to not be hundred-year floods. And the curve can shift before we're aware of it. Like, with this? We only get one new dot a year, which is why we create computer models so that we can run hurricane seasons over and over and over again with slightly changed variables to see what will happen.

And what we see with more energy in the global system is the curves shifting towards stronger, wetter storms. The more carbon we release in the atmosphere, the more these curves shift. And that is the future that we have to accept, and the one that we have to prepare for. And also, the one that it's good to try and understand a little bit.

So thanks for taking four minutes to do that.

John, I'll see you on Tuesday

That took substantially less than four minutes! I'm quite proud of myself. So here we are together in the end screen, I have so much time....

I'm going to Australia. See you at VidCon Australia, Australia people.

This shirt is the new Giraffe Love shirt designed by Ming Doyle. I like a lot. You can get it at

What else should I talk about? Sold out of backpacks! So... this is mine. You can't have it.

These are my favorite fidget toys because they're quiet. They make no noise. I can play with them while I'm on a phone call and it is not as noisy as this. Everybody hated me, and now they don't anymore.

There's a YouTube video I should make you go watch. Crash Course Film Production. With Lily Gladstone. So good. And the recent series on guns in America from Healthcare Triage. Really well done.

K bye.