Neonicotinoids are the most widely used insecticides in the world. But they've been linked to the decline of honeybees, which pollinate many food crops. And scientists now say neonicotinoids also harm many terrestrial, aquatic, and marine invertebrates. These pervasive insecticides damage sea urchin DNA, suppress the immune systems of crabs, and affect the tunneling and reproductive behavior of earthworms. They kill off insects that many birds, amphibians, and reptiles rely on for food.

The popular demand for avocados, once considered an “exotic” item, is having a devastating impact on a drought-stricken community in Chile. Lying within one of the largest avocado producing regions in the country, Petorca avocado plantations are in a battle over water rights, where claims of illegal water diversion are creating civil unrest.

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.

Honey bees, the essential pollinators of many major U.S. crops, have been dying off in massive numbers since 2006. This threatens the American agricultural system and the one in 12 jobs that depends on it. There is growing evidence that a new class of pesticides -- nerve toxins called neonicotinoids, which are used on many U.S. crops like corn -- may be toxic to bees.

(Earth Focus: Episode 52) U.S. domestic gas production is on the rise because of hydraulic fracturing, or fracking, a controversial method of extracting natural gas from shale rock by pumping millions of gallons of water mixed with sand and chemicals underground at high pressure. Environmentalists say this gas boon threatens water supplies and pollutes air. Now, as fracking expands around the world, so does growing resistance. "Earth Focus" looks at three countries on the new fracking frontline: South Africa, Poland, and the UK.

Gray wolves once ranged across North America. But by the 1930s, they were nearly extinct — trapped, poisoned and hunted by ranchers, farmers, and government agents. With protection under the 1973 Endangered Species Act, the wolf population rebounded. But wolves lost federal protection in 2011. Now, with hunting permitted in many Western states, the future of this once endangered species may again be in question. Can we live with wolves? "Earth Focus" travels to Montana and Wyoming to find out.

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.

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.

(Earth Focus: Episode 46) Between 70-210 million gallons of waste oil are illegally dumped at sea by commercial ships each year. In fish, marine oil pollution is linked to cancers, tumors, reduced growth rates, genetic side effects, and death. It is also toxic to seabirds and marine mammals including whales, sea otters, and dolphins. The new film "Oil in Our Waters" exposes this practice. Film director Micah Fink shares his findings with "Earth Focus" and explains new ways citizens can now help stop illegal oil dumping.

In Juliette, Georgia radioactive water flows from the tap. In Pennsylvania, three adjoining counties battle a rare form of cancer. One thing these communities have in common is their exposure coal ash. Coal combustion powers 40 percent of America’s electricity but generates 130 million tons of coal ash each year. Though it is known to contain carcinogens, coal ash is often dumped in unlined ponds where it leaches into groundwater. There is no federal coal ash regulation on the books—only a patchwork of state level standards.

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.

The debate over climate change remains polarized. Efforts to discredit the science of climate change by fossil fuel interests are a large part of the reason why says Michael Mann, Distinguished Professor of Meteorology at Penn State University. "If there was a huge industry that would stand to profit greatly if the theory of gravity were wrong you would see the theory of gravity being contested in our US Senate," he tells "Earth Focus" correspondent Miles Benson in an exclusive interview. Mann on the politics of climate change and the impact it has had on both science and policy.

(Earth Focus: Episode 50) This episode of Earth Focus looks at the dark side of shrimp and smart phone industries. Reports from Thailand, Bangladesh, and Indonesia uncover the brutal exploitation of people and the environment for profit.

Photo:  M. Yousuf Tushar / Flickr / Creative Commons

(Earth Focus: Episode 53) It is possible to rehabilitate large-scale damaged ecosystems, to improve the lives of people trapped in poverty and to sequester carbon naturally. John Liu presents "Hope in a Changing Climate," which showcases approaches that have worked on the Loess Plateau in China, Ethiopia and Rwanda. Produced in collaboration with the Environmental Education Media Project (EEMP).

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.

(Earth Focus: Episode 41) What do plants, snakes, molds, marine sponges, and cone snails have in common? They have helped develop medicines that save human lives. Biodiversity -- the variety of life on Earth -- is key to human survival. But plants, animals, and microorganisms are disappearing at unprecedented rates. What impact will this have on human health? Find out in this Earth Focus special report produced in collaboration with the Center for Health and the Global Environment, Harvard Medical School.

Oceans support life, yet they are overfished, polluted, and, with global climate change, are becoming increasingly acidic.

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.

Desert tortoises are a threatened species. Habitat destruction, diseases and other factors have reduced their numbers by up to 90 percent. Now flocks of ravens, that often live off human trash, are eating baby tortoises, reducing the odds of tortoise survival as a species. This documentary explores that impact, pointing out how people can change the environment through seemingly innocent actions.