Demographers are predicting that world population will climb to 10 billion later this century. But with the planet heating up and growing numbers of people putting increasing pressure on water and food supplies and on life-sustaining ecosystems, will this projected population boom turn into a bust?

For environmentalists protesting the Keystone XL pipeline, the battle is about more than just transporting tar sands oil from Alberta. It’s about whether the United States — and the rest of the world — will finally come to its senses about global warming.

Even as the impacts of climate change intensify, many Americans remain confused by the issue. In an interview Yale Environment 360, climate scientist Katharine Hayhoe discusses what rising temperatures will mean for the U.S., how to talk with climate skeptics, and what she would say to Texas Gov. Rick Perry to prod him into action on global warming.

Daunted by high up-front costs, U.S. homeowners continue to shy away from residential solar power systems, even as utility-scale solar projects are taking off. But with do-it-yourself kits and other innovative installation approaches now on the market, residential solar is having modest growth.

In the wake of the Fukushima meltdowns, some nations are looking to move away from nuclear power. But not China, which is proceeding with plans to build 36 reactors over the next decade. Now some experts are questioning whether China can safely operate a host of nuclear plants.

The contentious practice of hydrofracking to extract underground natural gas has now made its way to South Africa’s Karoo, a semi-desert known for its stark beauty and indigenous plants. But opposition is growing amid concern that fracking will deplete and pollute the area’s scarce water supplies.

Some skeptics have suggested the real culprit behind rising temperatures is increased solar activity. But a wide variety of data and experiments still provide no solid evidence to refute the scientific consensus that greenhouse gas emissions are the major reason the planet is heating up.

When Barack Obama won the presidency in 2008, environmentalists were optimistic that their issues would finally become a priority at the White House. So how is Obama doing? Yale Environment 360 asked a group of environmentalists and energy experts for their verdicts on the president's performance.

Phosphate has been essential to feeding the world since the Green Revolution, but its excessive use as a fertilizer has led to widespread pollution and eutrophication. Now, many of the world’s remaining reserves are starting to be depleted.

Exploiting North America’s largest oil deposit has destroyed vast stretches of Canada's boreal forest, arousing the ire of those opposed to this massive development of fossil fuels. Now those opponents are battling the Keystone XL pipeline, which would pass through environmentally sensitive Western lands as it moves the oil to market.

Even before this spring’s ominous clampdown on China’s public-interest lawyers, writers, and activists, the country’s fledgling environmental community felt the authorities’ noose tightening.

For eons, the polar marine food chain has been closely linked to the seasonal formation and retreat of sea ice. Now, as that ice rapidly melts in the Arctic and along the Antarctic Peninsula, this intricate web of life is undergoing major shifts, benefiting some creatures and putting others at risk.

Few places in the U.S. are as well suited to developing renewable energy as the contaminated sites known as “brownfields.” But as communities from Philadelphia to California are discovering, government support is critical to enable solar and wind entrepreneurs to make use of these abandoned lands.

Workers groups in South Korea report an unusually high incidence of cancers and other serious diseases among employees at Samsung’s semiconductor and other electronics plants. While the company denies any link, the pattern of illnesses is disturbingly similar to that seen at semiconductor facilities in the U.S. and Europe.

For millennia, the blanket of ice covering the Arctic Ocean protected the shore from damaging storms. But as that ice buffer disappears, increasingly powerful storm surges are eroding the coastline and sending walls of seawater inland, devastating Arctic ecosystems that support abundant wildlife.

A decade after a brutal civil war, the West African nation of Liberia has partnered with the European Union on a novel system for protecting its remaining forests — marking every harvestable tree so it can be traced to its final destination. But given Liberia’s history of conflict and corruption, will it work?

What if the ever-increasing amounts of carbon dioxide that are heating up the atmosphere could be used to produce an abundant supply of liquid fuels? The U.S. government and private labs are pursuing that Holy Grail of renewable energy — but for now the cost of large-scale production is prohibitive.

The disaster at the Fukushima plant in Japan convinced German Chancellor Angela Merkel that nuclear power would never again be a viable option for her country. Now Merkel has embarked on the world’s most ambitious plan to power an industrial economy on renewable sources of energy.

Nissan chairman Carlos Ghosn believes the technology currently exists to produce affordable, all-electric cars that will find a global market. In an interview with Yale Environment 360, he talks about Nissan’s new Leaf and why he is confident that, despite earlier setbacks, the time for all-electric vehicles is now.

Despite soaring rhetoric and some promising proposals, President Obama is repeating the same mistakes that have doomed U.S. energy policy to failure for 40 years. Until Obama and Congress finally put a true price on the fossil fuels America consumes, the U.S. will continue its addiction to foreign oil and domestic coal.