narrator: on this episode of "earth focus," climate change is forcing people to migrate in search of food and shelter, altering traditional lifestyles across the globe. in tijuana, mexico, haitians fleeing devastation are building a neighborhood as their dreams of entering the united states dwindle. while in mongolia, the traditional herding lifestyle is threatened as drought forces a new generation to the capital in search of opportunities.

[makelson derilus speaking spanish]

[greetings exchanged in spanish] [man on podium speaking spanish]

[man speaking spanish]

[both speaking spanish] [derilus speaking] isabel rivera-collazo: we think of migrants and refugees as these people that are coming to take over our country. we don't see that these are the people that got to the point that it was so hard for them to survive that it was easier to face death than to stay. because that's what they are facing when they decide to get on a boat or they

decide to cross a border or they decide to cross the desert, they're facing their own death, they're facing the death of their loved ones, their children, and that is a better decision than staying behind. reporter: look at the size of this storm on satellite at this hour. tonight a direct hit in haiti slamming ashore at 145 miles per hour. [indistinct voices]

[derilus speaking]

[whistle blowing] [cesar palencia chavez speaking spanish]

[pastor gustavo banda speaking spanish]

protester: apology. [indistinct crowd voices] protesters chanting: apology! apology! [derilus speaking]

[chavez speaking]

[man speaking] rivera-collazo: something said of climate migrants and environmental migrants is that often there is no population to go back to. the same thing happens with wars. so, those that migrate, they have a very tough time to be able to continue their way of life, especially if they are left alone within a city or a place that they don't know and there are no other people from their own country.

narrator: tijuana is adapting to an influx of haitian immigrants who are testing the city's ability to support them. in ulaanbaatar, the capital of mongolia, more than 600,000 nomadic herders have moved to the city, leaving a deeply- rooted lifestyle now threatened by climate change. [men speaking indistinctly] mitsuaki toyoda: people in mongolia have been practicing herding for centuries since the era of genghis khan. even today,

about one-quarter of the population live a nomadic life. [lamb bleating] toyoda: a dzud is a climatic term used in mongolia, which is characterized by summer drought followed by severe winter weather. the dzud used to happen

every 10 years or so, but it's becoming more frequent. [lamb bleating] [child chattering]

toyoda: there is about 750,000 people living in the care districts where infrastructure is very limited.

toyoda: the young people in mongolia is no different from any other young people living in other countries. they are very curious about what the urban life can offer to them.

toyoda: we need better long-term strategies to make sure that the livestock sector will become more sustainable. so it's probably better that we focus our assistance toward marginal herders, especially to try to protect their livestock so that they can maintain their traditional nomadic way of life.

announcer: "earth focus" is made possible in part by....

[mikael colville-andersen] whenever i think about milan, i've always thought about a diva. a classy, respectable, aging opera singer who's led a long life and has so many stories to tell. this city is standing at a crossroads, just like every other city in the world, in this growing age of urbanism. but here, the conversation is amplified. there is a growing hunger for real urban change. i want to find out which path milan is choosing and how it will future-proof itself using the power of urbanism and community engagement. milan, show me what you've got.