- Scientists are confident that we've already crossed at least one major tipping point.

And if you're familiar with this term, you know it usually means disaster.

Sudden irreversible shifts like the breakdown of entire ecosystems, the melting of ice sheets, the collapse of major ocean currents that regulate our weather.

The list goes on and on.

- It's horrific to imagine it's almost an unimaginable humanitarian catastrophe that's a billion people or more.

- And many of these climate systems could likely begin to tip at 1.5 degrees Celsius of global warming, a threshold that for the first time in human history, our planet has crossed for an entire calendar year.

So today we'll explore the tipping points scientists are most worried about, reveal the one that's already here and see how it's already beginning to change our world.

There's a common idea that human psychology is to blame for our lack of climate action, specifically something called psychological distance.

The theory goes that because climate change feels distant or unfolds gradually, people don't feel motivated to act.

But this might not actually be true.

In fact, surveys show the opposite.

76% of Americans say that climate change is already affecting their daily lives.

Ironically, the greatest risk from climate change may come from the opposite problem, that it does not always unfold gradually.

Sometimes the shift from one state to another happens suddenly, and by the time we notice it may already be too late.

- Change becomes usually more rapid and much harder to reverse.

And sometimes it does manifest as a quite distinct shock.

- And this is what makes tipping points so risky.

They can suddenly tip and then that rapid change in the system becomes self-propelling.

- And that means even like a, a small change makes a big difference for the for the system.

- And our decision making tools don't adequately factor in these state shifts.

The 2025 tipping points report highlights that tipping points present distinct governance challenges compared to other aspects of climate change.

Changes in these large climate systems often accelerate compound and then suddenly they tip.

And that's what makes these tipping points so different from most everyday risks.

They're non-linear, so it's difficult to understand and plan for.

- If once they're underway, they're hard to reverse.

We should be really erring on the side of caution and trying to avoid getting into that situation, right?

- And because they're often impossible to undo, at least on human timescales, it's important that we understand tipping points the best we can.

But the challenge is that even though scientists can estimate when a system will tip with models known as tipping ranges, we don't know exactly when a system will tip in the real world.

- It isn't always obvious immediately when we've crossed a tipping point because different systems have their different time scales to our human perception.

And some systems like melting down an ice sheet are still relatively slow by human perception, whereas other things like having a monsoon or not having a monsoon are really fast.

- It's like walking in the dark near a cliff.

You don't know you've crossed the edge until you're already falling.

So which of earth's tipping points should we be most worried about and what happens when we cross them?

Well, there are a couple different ways to understand the risk from tipping points.

So let's start by looking at which ones have the highest impact on the world and civilization.

So let's start with the AMOC or the Atlantic Meridional Overturning Circulation.

- What the AMOC, as we call it, is doing is transferring us almost unimaginably large amount of heat across the equator.

- You can think of the AMOC as a giant heat conveyor belt moving warm surface water north and cold deep water south.

It's one of the main reasons Western Europe is so mild.

Without it winters there would become dramatically colder on the order of five to 10 degrees Celsius lower in many places.

London could feel more like present day northern Canada in the winter.

And sea ice could reach as far south as the UK and parts of mainland Europe.

And as we warm beyond 1.5 degrees, we move further into the AMOC's tipping range.

And the AMOC also affects another important climate system, the position of the Inter-tropical Convergence Zone, which is responsible for the monsoon season in India and West Africa.

- When you don't have this massive transfer of heat by the ocean circulation, you shift that whole band of rainfall to the south.

- That could mean a failed monsoon season in India and West Africa threatening food security and water supply for an entire region.

- If the rains fail and that's it, you know, the monsoon never comes back.

It's horrific to imagine it's almost an unimaginable humanitarian catastrophe that's a billion people or more.

- But the Indian and West African monsoons aren't the only tipping points an AMOC collapse could help trigger.

- And we know it connects up the whole climate system making it more likely to tip the loss of the West Antarctic ice sheet and parts of the East Antarctica ice sheet.

Because a load of heat has got left behind in the southern ocean.

- West Antarctica is far more vulnerable and alone holds enough ice to raise global sea levels by about five meters.

East Antarctica holds another 58 meters of potential rise.

The consequences of even a fraction of that melt would be catastrophic.

So the AMOC is the tipping point that Tim believes probably has the greatest consequences on its own.

But there are other tipping points that may be caused for even greater concern because they're likely much closer to tipping.

Take permafrost for example, it's frozen ground.

Layers of soil, rock, and ice rich sediment that locks away an enormous amount of carbon.

In fact, Arctic permafrost holds roughly twice as much as what's currently in the atmosphere.

As the Arctic warms, scientists are increasingly worried that parts of this frozen landscape could thaw abruptly.

Releasing massive amounts of greenhouse gases and triggering further warming in a dangerous feedback loop.

- We're also seeing in the permafrost, in the high arctic kind of craters and lakes forming and evidence of bits of the permafrost, at least thawing abruptly.

And the big question is, is that gonna escalate in scale?

- But that isn't the only system that's entering its tipping range.

- Then there's two big ice sheets, both Greenland and West Antarctica where we're struggling to rule out that they're not past the tipping point.

- Since they're these large slow systems, they're difficult for scientists to monitor.

But regardless, the signs are concerning, especially for West Antarctica.

But there's one more system that scientists are even more immediately worried about.

- Well, at the moment we are thinking that warm water coral reefs may have passed a tipping point.

We are temporarily at like 1.5 degrees centigrade global warming, and the experts had estimated that their tipping point could be at like 1.2 degrees centigrade, global warming.

And kind of consistent with that we're seeing this just unprecedented extreme dieback of reefs.

- And even if we act fast, 70 to 90% of coral reefs could die in the coming decades without any action.

It's nearly all of them.

So each one of these climate systems could completely change if they tipped and many of them are already within their tipping ranges.

But there's one tipping point that nearly all scientists I've spoken with agree that we've almost certainly already crossed and it could change everything.

When Tim popularized climate tipping points in his 2008 paper, he wasn't just talking about these big scary climate tipping points like the collapse of the AMOC and the death of coral reefs.

He was also talking about another kind of tipping point, positive ones.

- When I was started telling the world about the climate tipping points nearly 20 years ago, I kind of knew the potential for the positive tipping points, but we were so far away.

But what we've seen in recent years as they start to arrive and then it's much more persuasive.

- And according to Tim, renewable energy has almost certainly passed a positive tipping point.

And it's not just Tim who believes this, the UN agrees as well.

- It's the cheapest form of new power generation in most of the world now.

- So far, solar power has followed a pattern known as Wright's Law, the idea that technology becomes cheaper as we build more of it.

In fact, solar has shown a learning rate of about 20%, meaning that every time global solar capacity doubles cost falls by roughly 20%.

This steady decline is one of the main reasons solar has become the cheapest source of electricity in much of the world.

- Today, you know, 90% of the capacity, electricity capacity being built in the US and worldwide is clean energy.

- Since 1976, the cost of solar has dropped over 99%.

In 2024 alone, solar costs dropped by 35% and battery components fell by as much as 54%.

- In about half the world, it makes economic sense to shut down an existing fossil fuel power station with good life left in it and replace it with brand new renewables and battery storage.

- And that shift isn't just happening in wealthy countries.

Places that haven't had reliable electricity are now importing more solar than ever before.

- We've got the cheapest electricity ever and it's just starting to give access to electricity to people who've never had it.

600 million of who are in Sub-Saharan Africa.

- Solar adoption in Africa skyrocketed between June 2024 and 2025.

Imports rose by 60% with 20 countries buying record amounts of solar panels.

And we're seeing similar surges across the globe.

- But even countries that are more functional like India have really seen a, a dramatic expansion of of solar energy in recent years because it is so much cheaper than everything else.

- And this growth is occurring across a number of sectors of renewables.

- Some big sectors are, are closer to the tipping point than others and and actually one positive tipping point can bring forward the next, which is kind of cool.

- So yes, the progress is mind blowing.

Renewables are scaling faster, electrification is increasing, and efficiency is improving, and fossil fuels are projected to decline.

But despite all of this news experts say this change needs to happen much faster because we don't know exactly when we will cross these climate tipping points.

So every fraction of a degree matters, and that is scary, especially given the recent rise in petrostates doubling down on oil and gas.

I mean, globally fossil fuel subsidies are almost nine times higher for oil and gas than for renewables.

So even though we've crossed a crucial positive tipping point that could help us avoid the worst impacts of these devastating climate tipping points, the risk remains that it might not happen fast enough.

But regardless, there might still be some hope.

- But while I think the US is definitely gonna be moving backwards or certainly slowing down our, our decarbonization pretty dramatically in the next four years, I don't think the same is true for the rest of the world.

- Many countries are taking advantage of the opportunity to compete in the renewable space.

- China's on track to potentially peak its emissions as early as this year and start declining.

So that's, you know, really good climate news.

- They manufacture over 80% of solar panels, about 75 of EV batteries and 60% of wind turbines globally.

They're on track to become the world's first electrostate, meaning they're the largest deployer and producer of renewables.

And with the renewables tipping point crossed petrostates will inevitably fall behind.

- China is becoming the world's first electrostate while the US is doubling down on being a petrostate.

Since now we are the world's largest oil producer and world's largest gas exporter, we are doubling down on the technologies of the 21st century and we really risk being left behind.

- So what's the takeaway here?

Well, we aren't necessarily doomed, but we are in a battle of the tipping points, a race between climate change and clean renewable energy.

We're at a critical moment where if we invest enough resources into renewables, we could tip into a cleaner, safer, healthier future.