How significant would it be if America’s 29 million small businesses increased their energy efficiency and reduced their emissions? Judging from the example of one California entrepreneur, the impact could be far greater than you might expect.

Across the Far North, populations of caribou — an indispensable source of food and clothing for indigenous people — are in steep decline. Scientists point to rising temperatures and a resource-development boom as the prime culprits.

As Scotland asserts its identity and its autonomy,
environmentalists are working to restore its denuded landscape, planting native forests, creating wildlife corridors, and reintroducing species that were wiped out centuries ago.

Ecuador's Yasuni National Park is one of the most biodiverse places on Earth and is home to remote Indian tribes. It also sits atop a billion barrels of oil. Now, Ecuador and the United Nations are forging an ambitious plan to walk away from drilling in the park in exchange for payments from the international community.

Consumers now have little information about the true ecological impacts of what they buy. But that may be about to change, as new technologies that track supply chains are emerging and companies as diverse as Unilever and Google look to make their products more sustainable.

LEED certification has emerged as the green standard of approval for new buildings in the United States. But the criteria used for determining the ratings largely ignore factors relating to human health, particularly the use of potentially toxic building materials.

While some studies have suggested that frequent use of cell phones causes increased risk of brain and mouth cancers, others have found no such links. But since cell phones are relatively new and brain cancers grow slowly, many experts are now recommending taking steps to reduce exposure.

With 20 percent of the world’s population but just 7 percent of its available freshwater, China faces serious water shortages as its economy booms and urbanization increases. The government is planning massive water diversion projects, but environmentalists say conservation — especially in the wasteful agricultural sector — is the key.

A dispute between Egypt and upstream African nations has brought to the fore a long-standing controversy over who has rights to the waters of the Nile. The outcome could have profound consequences for the ecological health of the river and for one of the world’s largest tropical wetlands.

New technologies, feed-in tariffs, and tax credits are helping propel the small wind industry, especially in the United States. Once found mostly in rural areas, small wind installations are now starting to pop up on urban rooftops.

Flying dwarfs any other individual activity in terms of carbon emissions, yet more and more people are traveling by air. With no quick technological fix on the horizon, what alternatives — from high-speed trains to advanced videoconferencing — can cut back the amount we fly?

The practice of “commissioning,” in which an engineer monitors the efficiency of a building from its design through its initial operation, just may be the most effective strategy for reducing long-term energy usage, costs, and greenhouse gas emissions from buildings. So why is it so seldom used?

Is human activity altering the planet on a scale comparable to major geological events of the past? Scientists are now considering whether to officially designate a new geological epoch to reflect the changes that homo sapiens have wrought: the Anthropocene.

Insecticides such as DDT have long been used to combat the scourge of malaria in the developing world. But with the disease parasite becoming increasingly adept at resisting the chemical onslaught, some countries are achieving striking success by eliminating the environmental conditions that give rise to malarial mosquitoes.

California’s high-tech giants have long used renewable energy to help power their Silicon Valley headquarters. Now, companies such as Google, Adobe Systems, and eBay are preparing for the next step — investing in off-site solar and wind installations and innovative technologies that will supply their offices and data centers with green electricity.

In Africa and elsewhere, burgeoning population growth threatens to overwhelm already over-stretched food supply systems. But the next agricultural revolution needs to get local — and must start to see rising populations as potentially part of the solution.

Hydro fracturing is a profitable method of natural gas extraction that uses large quantities of water and chemicals to free gas from underground rock formations. But New York City’s concerns that the practice would threaten its water supply have slowed a juggernaut that has been sweeping across parts of the northeastern United States.

As the world warms, sea levels could easily rise three to six feet this century. But increases will vary widely by region, with prevailing winds, powerful ocean currents, and even the gravitational pull of the polar ice sheets determining whether some coastal areas will be inundated while others stay dry.

In recent months, protests over the severe illnesses caused by China's heavy industries have resulted in a crackdown on polluters. Leading the charge has been the state-run media, which the central government is now using to gain control over corrupt local authorities and powerful commercial enterprises.

Two billion people worldwide do their cooking on open fires, producing sooty pollution that shortens millions of lives and exacerbates global warming. If widely adopted, a new generation of inexpensive, durable cook stoves could go a long way toward alleviating this problem.

Living on shifting land formed by river deltas, the people of Bangladesh have a tenuous hold on their environment, with cyclones buffeting coastal zones and rising seas posing a looming threat. But, as this Yale Environment 360 video report by Jonathan Bjerg Møller makes clear, many Bangladeshis already are suffering as a growing population occupies increasingly vulnerable lands.