Two cities, San Francisco and Freetown, brace for climate change using vastly different methodologies. San Francisco's developers are building expensive real estate on floodplains as officials try to heed expert projections on future sea levels. On the other side of the world, a deadly mudslide caused by torrential rains and deforestation in Sierra Leone shows the consequences of city planning that doesn't take climate change into account.

Anticipating future water needs, two regions on opposite sides of the world turn to technology for answers. Western Morocco, near the Sahara Desert, is currently facing unprecedented drought and groundwater mismanagement. But an ancient method of gathering moisture from fog is being taught to 13 villages, allowing people to have a level of local control over their most basic need. In Central Valley, California, the food basket of the world uses nearly 80 percent of the entire state's water supply.

Communities and innovators all over the world are creating new sustainable food sources that are resilient to climate change and growing populations. In Madagascar, we see how villagers are closing off marine areas to allow the fish supply to replenish at a natural pace. In San Diego, California, aquaculturists are exploring open ocean farming as a more sustainable model for the fishing industry.

Los Angeles is one of the biggest biodiversity hotspots in the world, despite its smog, urban sprawl and snarling freeways. At least 20,000 native and non-native plant and animal species are thriving despite human interference, and in some cases because of it. How can people help make urban habitats more welcoming to non-human urban dwellers?

(Earth Focus: Episode 45) The future -- Swedish style. Stockholm's Royal Seaport, a rundown district in Sweden's capital, is set to become a model of energy efficiency. Plantagon, a leader in vertical urban agriculture, has an answer to feeding the mega cities of tomorrow -- urban skyscraper farms. The Stockholm eatery Nyagatan, cuts carbon emissions by going local and organic. Solvatten, a Swedish water purification system that uses sunlight is now being used around the world.

Louisiana still is learning from Hurricane Katrina. Forecasts are dire for Louisiana to experience the second-highest sea level rise in the world. There is a big movement brewing in New Orleans to build adaptive "resilience zones." In Southeast Louisiana, the native peoples of the Isle de Jean Charles have become the first U.S citizens moving within their homeland displaced by climate change.