- Did you know that urban areas are responsible for a whopping 60% of global greenhouse gas emissions?

That's a lot, but the good thing is, cities also hold the key to creating solutions for climate change.

But first, let's hear a little bit more about the problem.

(bright gentle music) Our planet's life support systems are in trouble.

From the air we breathe to the water we drink, things are looking pretty grim.

And guess what's making it worse?

Urbanization.

Cities are growing at an insane pace.

By 2050, they could be triple the size they are now.

To build all these new homes and buildings, we're clearing forests, mining mountains, and sucking up precious groundwater.

This is bad news for plants and animals, and it's not good for us either.

On top of this, climate change impacts tend to worsen social and economic disparities, especially in developing countries where cities are experiencing a surge in world urban migration.

We spoke with legendary geographer, Gray Brechin, about his perspective of the urban environment relationship and what the future might hold.

- I wanted people to understand the total inseparability of the city and the countryside that it draws upon.

I really love cities, and I spend all my vacations in cities, so I love what they have to offer, because they are sites of human transformation and liberation.

And so I love cities, but you know, I have a very conflicted view of cities as well too.

We have to understand that particularly as we're celebrating growing cities to understand what they're actually doing to the biosphere of the planet we're on.

(gentle solemn music) - So how do cities grow?

Typically, urban areas expand by pulling resources in from the surrounding environment and putting out waste.

As you can imagine, it's a pretty extractive process.

It doesn't need to be that way.

- I see cities as being like organisms.

They sustain themselves and grow by consuming vast amounts of natural resources and energy.

And in the process, they transform that into corresponding amounts of waste, waste products.

But the most important waste of all it turns out, is invisible, and that's greenhouse gases.

Cities produce vast amounts of greenhouse gases in the process of using up fossil fuels, but it's invisible.

- [Meg] The good thing is that cities have an immense opportunity to lead widespread climate action.

First and foremost is engaging city planners and community leaders to include vulnerable populations in climate solutions.

Examples include investing in green infrastructure, supporting low carbon public transportation, and expanding urban parks and gardens.

Urban areas by the coast can also use mother nature to prevent flooding.

Natural solutions like planting mangroves not only support local biodiversity, but they also can lead to significant emissions reductions while delivering economic benefits to urban communities.

The list goes on and on about ways cities can have great impact.

- You know, when I was growing up, the Bay had a notorious stink.

We called it the Bay Smell, you know?

And I could smell it from four miles away, because we were dumping all of our raw sewage and garbage, and we didn't think anything about that until about the time that Rachel Carson wrote "Silent Spring" in 1962, which was a sea change because people began thinking then about what we were doing to harm our environment and the planet itself.

And because of that, we got things like the Clean Water Act, the Clean Air Act, the Endangered Species Act, and the world has become, in some ways a better place.

(bright gentle music) - As urban areas grow, there's an incredible opportunity to shift from an extractive to symbiotic relationship with nature.

Investing in climate forward adaptations and local solutions hold the key to helping our cities thrive in a changing world.

Until next time, happy exploring.

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