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.

The realities of milk production are forcing dairy communities across the globe to rethink the dairy production process. In this episode, we travel to a village in Kenya where the commercialization of camel milk is proving a sustainable solution in the face of drought. In Northern California, the heart of the U.S. dairy industry is finding innovative alternatives to limit the use of water and manure emissions.

Wood is found in countless products consumers use every day. In fact, lumber is closely connected to the world’s economy – a country’ s importation of lumber tends to rise in correlation with its gross domestic product. Following groups like “Guardians of the Forest,” we explore illegal lumber poaching in the forests of Brazil and Oregon, where citizens and scientists are working together to combat the illegal lumber trade.

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.

Solar power is changing lives in unexpected places. At the Barefoot College in Zanzibar, Muslim women who have traditionally been marginalized in the workforce are learning solar installation and bringing it back to their villages, which are primarily powered by candles and paraffin lamps. In East Los Angeles, formerly incarcerated individuals are finding green job opportunities as they transition underserved communities into solar power.

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.

The ocean is a sponge for all the greenhouse gas emissions we produce, and entire aquatic ecosystems are beginning to collapse. Off the coast of California, the disappearing abalone population is raising flags about ocean health and the lasting impact of rising sea temperatures, acidification and pollution. Various teams of scientists, volunteers and businesspeople are collaborating to protect underwater species threatened by the invasion of sea urchins.

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?

The global demand for oil and gas has long-lasting impacts on the communities that supply it. In Alaska’s Arctic National Wildlife Refuge, powerful native communities are at odds over an oil exploration and drilling plan that will boost their economy but have long-term consequences on native species and their environment. In California’s Kern County, the mayors of two neighboring towns face off on the economic benefits and health risks of oil production and their vastly different visions for the most sustainable path to the future.