narrator: on this episode of "earth focus," two cies-- freetown, sierra leone, and san francislifornia-- continents apart, vastly different turally and economically, yet facing the same struggle to adapt to rap urbanization, all set against the backdp of a dramatically changing climate. [film advance clicking]

man: oh, no! woan: the red cross says more than 600 people are now missing and that more than 200 havekilled after heavy rain caused a severe mudslide in the west african

[car horns honking]

[insects chirping] amarasekaren: oo oo oo! what's happening? what's happening? no big problem, huh?pr ok. when we gelem...

man: whoa! [men shouting] [indistinct conversation]

narrator: while freetown residents fight for accountability, in san francisco, climate change isn't debated as much as it's igated. biions of dollars are pouring into the bay area, but is tech-driven development f prepar a sea level that's rising? scholl: san francisco is experiencing a tremendous building boom and has been for the last 5 years. tam: we have ucsf hospital. we have the warriors coming. we have a bunch of new apartment buildings.

scholl: you have corporate headquarters of facebook, google, microsof christensen: we realize we live in such so amazing place with much creativity and innovation. people in the tech industry all over town, all over the bay area commuting back and forth. there's an energ. renteria: in mission bay, everyone pretty much works in te start-up. h woman: ie 3 cappuccinos for here. renteria: i'll do a coffee. ok. thanks. i'm considered millennial. we kind of are free spirits, and

we don'eve so much ed just full-time gigs. i work in social marketing, so it's definitely a new industry. a lot of people don't quite understand it, but i runr social living. the really cool thing about a job in sociamedia or just tech is that you can work remotely. coffee shops are free. yes, san francis is really expensive. th se is no other place like francisco where you're going to hal access to the technoy, to the communities, to just t people working in the industry. it's just one of kind, and it's totally worth it. i sold my car, and i pretty much walk everywhere now, and i got rid of a lot of stuff, and i live in a very small apartnt , but it's totally worth it just to have access to everything. yay. cheers.>> cheers. renteria: i just learned about the sea level rising, and i didn't know about that beforee moved here. does it concern me? yes, because i eventually want

tobuy property here and ha a family here, but i didn't know about that, a'm not too informed, so it's not something that i'm really too concerned about right now. i am scad now, though, learning that that's a possibility. christensen: people under 40n living heree bay area today are very, very likely to see unprecedented annual flooding arod the bay in their lifetimes. in jacob: it's to be fantastic in a city that is so vital and known foits innovation that we're going to be able to build this great venue here. christensen: a lot of these new buildings by the end of the century, including the golden stateularriors' new arena, have the ground floors at least potentially flooded or

basement parking flooded. the warriors arena is, you know, contemplating maybe someday putting in flood gates so that their garageson't flood. they're thinking of raising pedestrian access so that itul be out of the water. san francisco itself, y know, built a seawall in the late 1800s to protect itself and this new land that had been created. you know, right now, san at spending $5 billion to repair and reinforce that seawall for another century. scholl: the areas that haveeen the least developed historically are the marginal lands around the bay, some of which are salt flats. others are abandoned piers, and they're being rehabilitated because there's basically no place in the bay area

to build, and they're being built upon as quickly asst possible by moly megacorporations that are trying to ximize their value by building very expensive developments. to me, it feels like sort of climate denial light. we found in 2015 that about $21 billion'ts worth of developmen was happening right in that coastal zone. is a tremendous amount of money to be made to develop in those areas. by the year 2100, we found, ere's a threat that sea level rise could, on a really bad day, flood land all around the bay exactly where most of the waterfront development is happening, and then they're goingo have to figure out how to invest public dollars to protect what we're building right now. tam: mission bay was once a bay. it was an inlet of the bay.wa itmarshy and

brackish and kind of shallow. mission bay is finally getting built after many, many years of planning and agreements around infrastruture. there are some really important institutions that are there buildings, as well. it's an area that is rapidly a becoming part of the urban fabric of san francisco where it really was once seen aslike, a strange and unoccupied place, but, because we planned it in an era before we were thinking level rise, it's also very low-lying, and it's one of the city'more vulnerable places to future sea level rise. scholl: the problem is that the land valuable because it's now land. devepment companies couldn't not build there. there were billions of dollars ut real estate to be had, they built it in probably one of the worst places they could have. it was a bay in the past, and it most likely will be a bay in the future. tam: we picked this part of the shoreline for a study around design concepts for future sea

level rise because it's the lowest lying area on the eastern waterfront. it's the place that's going to flood first, and so we thought it was the right place to sparko ersation around what are design alternatives or choices that we can make in the future the mouth of mission creek near at&t park. we'll have a really beautiful public space that people might not even realize is designed for flood protection. habitat and parks and a place where people can access the bay. we want to have a lot of commercial activity in our city. we want more housing. we definitely ne affordable housing to solve some of the bay area's biggest challenges, but alongside that, we have to do something out future sea level rise. ideally, we'll have a lot of people enjoying the terfront, and during storm events, we'll have some kind of way ofhr protecting peoplegh some kind of barrier or just because we have shallowed the channel in some way that makes it no longer super threatening when here's a super high tide.

herrera: the science is undeniab. climate change is altering our planet, placing many of a our communitiesrisk. urwe must prepare for a f that directly confronts these changes. theefendants are chevron, exxon, bp, shell, and conoco phillips. these funds will be used top for seawalls and other infrastructure needed to deal with sea level rise. we have some real risk that's going to require some billions and billions of dollars of inent by san francisco on infrastructure if we're going to stop catastrophicoss, so that's what we're looking at. a lot of our developments a occurring along the waterfront. our lawsuit is a part of that. i want to have this abatement fund that has been created now to ensure that we can fund the infrastructure improvements that were going to need to ensure that tse developments go forward without the threaof sea level rise.

scholl: politics inan francisco is funny. there are a lot of really enlightened views. on the other hand, it's probably not enough to prevent the business community from making things even worse right on the waterfront. gchristensen: we'reoing to have to adapt.to it's going ake that creativity and energy and capital. the question of how do we balance that economic developmentthe investment in protecting it, with the needs of people and the environment is one tou know, we're going to find ourselvesov askin and over again here in the bay area and around the world. (upbeat m)

[narrator] it was a case of being in the right place at he right time. [rüdiger] it wasn't anything that we were familiar with in this area. [narrator]n new species, hidingain sight. [rüdiger] it was a coincidence that i was not only interested in the general diversity of invertebrates, ap but alson to be a specialist on worm-snails. [narrator] a nonnative worm-snail so well hiddenotonly an expert could t among the ever-growing marine fauna attaching to the shipwreck. y [rüdiger] tcall it the. [narrator] and, that's because, for now, d it's only fo one place. [rüdige we have not seen th anywhere other than the vandenberg wreck. [petra] changes may go unnoted for a very long time because nobodyoo l aitt .