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I'm going to show you a graph that the federal governmen doesn't want you to see.

For decades, NOAA tracked the rising cos of climate disasters in the Unit Their Billion-Dollar disasters graph showed how often extrem weather events caused catastroph Then in 2025 funding for those updates was cu And it wasn't an isolated decisi The Trump administration, has been removing informatio about all sorts of inconvenient But studying severe climate sce actually been unpopular for a lo As soon as you talk about any kind of extreme risk in climate change, you are You are an alarmist.

And this matters.

In recent years, the most likely projections have come down thanks to the rapid pace of renewable energy adoption.

But future progress is far from guaranteed.

Most countries don't actually have the tool to meet their climate targets an We've spent a lot of time on th looking at how progress is made, but given the current reality, we need to understand what happens at the upper ranges of warming projections.

And it's not the warming alone that puts us at risk.

A world with three degrees of wa in which you also have large levels of inequality geopolitical strife and conflict a lack of trust in public insti and a huge amount of misinformat that is a worl which may actually result in cat Luke studies what caused past civilizations to collapse, how climate contributed what we can learn about the risk So in this episode, we're going to learn how the wo plausibly ends- according to sci 18% isn't exactly a small chance You're not going to walk into a if there's an 18% chance of it c In most high stakes fields studying, the worst cas scenario is normal in medicine, nuclear engineering, understand everything that could go wrong isn't seen as pessimism but rather a basic risk manageme Whenever we try to deal wit any kind of risk management prob we always think through worst ca scenarios.

You don't engineer a ca then not test it in a high speed You always look at the worst cas whenever you're doing good risk management.

That is particularly tru in conditions of deep uncertaint but when it come to the most consequential system of all Earth's climate we just don't like to talk about we've actually done text mining of IPCC reports to look at how frequentl different temperature scenarios And what we see is across all IP So the last couple of decades h end warming scenarios are substa underrepresented compared to lo ones like 1.5 and two degrees Ce So let's talk about it.

What is the worst cas scenario and how do we avoid it?

Under current policies, we are likely to hav a temperature rise of somewhere between 2.6 to 2.9 degree Celsius by the end of the centur But that's the very likely range There's actually a much larger r That around three degree estimate makes a couple big assu First that the policies and promises m the 2016 Pari Climate Agreement are broadly fo and that requires stron political will and global cooper In the long term, we don't really know how the wor going to look geopolitically.

So we can't rule out a world wit climate policy.

But there's another source of un that's out of our hands.

Climate sensitivity is a measure of how much the Earth warms in respons to an increase in carbon dioxide And that alone could tip us into a very different world.

Climate sensitivity could be fa of three degrees, because the pl basically just doesn't work in that we might have thought it do We know it will be significantl in the future, but the further we look out, the more difficul it gets to say exactly how much According to current policie we're on track to reach approxim 670 parts per million of carbon by the end of the century.

Even if we only have 560, there be an 18% chance that we go abov We haven't seen temperature that high in about 15 million ye when sea levels were tens of met higher than today.

And at that level of warming many of Earth's major climate sy would either cross their tippin or be pushed into severe risk.

So not great.

18% isn't exactly a small chance You're not going to walk into a if there's an 18% chance of it c It would take the world a long tim to reach that new far hotter sta But when you take into account the complexities of human behavior the timeline can speed up dramat Because in addition to heating t climate change destabilize the systems we most depend on- both the natural systems and the human ones.

And when those systems come unde at the same time, history shows they can fail very quickly.

Laurie compares the system failu to a ship navigating a storm.

When youre a crew on a shi trying your best to sail around One of things at the forefront mind is protecting your crew's a navigate, while also handlin the worsening impacts of the sto And that can go 1 or 2 ways you can manage to allocate your and your attention, and maintai so that you're still able to nav whil the worst of the storm rains dow Or it could go the other way, where you becom so overwhelmed that you fail to and then you drift further into and ultimately you're overwhelme This is what researchers call de risk.

And it's one of the fastest way climate change could push the wo towards collapse.

Chaos caused by climate extreme worsening consequences of climat can actually begin to get in the of acting on climate change.

And we've already seen what cli induced derailment looks like in Back in 2010, Russia was hit by wave which decimated its crops o Because of that, Russi introduced a cereal export ban.

The price of staples, in particu globally went up.

That doubled bank usage in the U but it also seemed to cause increased political strife in Egypt.

And interestingly enough the rise in food prices and the of the price of bread in Egypt pretty well with the Arab Spring and of course, the huge political upheaval.

Climate stress on its own didn't cause the Arab Spring, but it acted as an accelerant, fragile systems past their break and causing the collapse of gove across the region.

We can see similar cascading ri emerging here in the United Stat After extreme rain and prolonged drought in Los Angeles two fires burned 16,000 homes.

Insurance is the critical thing underpins all of capitalism, bas When you're in a situatio where climate extremes are playi worse than you thought the basically the maths start to bre The insurance industry has so f weathered the storm by raising r and dropping customers, but its availability in the region are u If insurance is no longer availa then other financial services aren't available, right.

Just think of houses.

If you can't insure house you can't get a mortgage on a ho We don't know how many more natural disasters like this our and economic systems can withsta But we can already se the derailment theory at play, where climate disaster make us less able to take climat You have almost the biggest wake that America has ever had on climate change.

But then at the same time, you h then president elect of the United States sayi this wasn't to do with climate c They basically said, look, clim is in causing these disasters.

it's climate fanaticism that causes these disasters.

Laurie believes this derailment risk could easily cause us to spiral closer and close into the storm of climate change So all of this made me wonder how is this likely to play out?

And clearly, our expert have been spending a lot of time thinking about this.

Like, a lot Imagine it's the early 2030s and climate change has only gotten worse, and the is even less stable than it is t And then suddenly extreme cold h North Western Europe.

This is because a ke bit of the Atlantic circulations has collapsed, something called Atlantic Subpolar gyre.

The subpolar gyre is an importan part of the AMOC.

It's an enormous circulation sy that carries heat from the tropi to the northern latitudes and re global weather.

What then happens is tha part of the world, becomes very That then leads to a set of big corrections of basically in financial markets, because they didn't anticipate this wild caught happening.

And it leads to bit of a financi across the Euro-Atlantic area that spreads to the rest of the causing lots of destabilization.

And if the south polar gyre col it would very likely be a warnin for the rest of the Amoc.

But by this point, the world is deraile politically, economically, socia And that makes responding to a n enormous threat far harder.

Fast forward a number of years and the full circulation then co It doesn't just make Europe much therefore messing up major food growing regions in Eu It also disrupts the majo monsoons globally, including ove India and Pakistan.

And increased tensions between India and Pakista is something we really don't wan These two countries, are both n armed, they have a history of ho between each other and they share a water resource, a water resource that is going drying up due to climate change.

Any nuclear exchange, even a limited one, could trigger what call nuclear winter.

This occurs when nuclear explosi cause so many cities to burn that soot injecte into the atmosphere blocks sunli and triggers widespread crop failure and mass starvation.

Even just a regional nuclear war could kill around 2 billion people, mostly through f and a larger, full scale nuclear war looks pretty much like the end of the world with over 5 billion deaths.

And that's a conservative estima During the Cold War, we were able to avoid all out nu once the cascading impacts it would have were actually stud and widely understood.

Once we understood that a nuclea would mean game over, the idea of nuclear deterr became a priority.

And in the same way, understanding the worst case scenario of climate change, which also looks a whole lot like the end of the world could be the very thing that sav Because the more clearly we see the climate endgame, the bette our chances of never reaching it In our next episode of weathered we'll look at the solutions that can help prevent the worst scenarios we've been talking abo see you next time on Weathered.