The Copenhagen summit turned out to be little more than a charade, as the major nations refused to make firm commitments or even engage in an honest discussion of the consequences of failing to act.

As the world weighs how to deal with warming, the idea of human manipulation of climate systems is gaining attention. Yet beyond the environmental and technical questions looms a more practical issue: How could governments really commit to supervising geoengineering schemes for centuries?

Governments from the developed world will never come up with enough money to help poorer nations adapt to global warming and implement renewable energy technologies. The solution may lie in using a modest allocation of government funds to spur private sector investment in green energy projects in Africa, Asia, and Latin America.

As the UN conference enters its second and decisive week, the calls for strong global action to deal with climate change do not appear to be penetrating inside Copenhagen’s Bella Center.

The way that climate scientists have handled the fallout from the leaking of hacked e-mails is a case study in how not to respond to a crisis. But it also points to the need for climate researchers to operate with greater transparency and to provide more open access to data.

Hampered by a slow-moving Congress, the Obama administration is offering only modest greenhouse gas reduction targets at the Copenhagen conference. But limited federal action does not mean the U.S. is standing still: More than half of the 50 states are already taking steps to reduce emissions on their own.

The recent controversy over hacked e-mails in the climate science community has emboldened global warming skeptics who dismiss the notion that humanity is dangerously heating up the planet. But James Hoggan, founder of the Desmogblog, is taking on the deniers, accusing them of cynically obfuscating an issue long ago settled by mainstream science.

As wild fish stocks continue to dwindle, aquaculture is becoming an increasingly important source of protein worldwide. Now, a growing number of entrepreneurs are raising fish in large pens in the open ocean, hoping to avoid the many environmental problems of coastal fish farms.

Twelve years ago in Kyoto, the world was poised to act on a climate treaty but looked for a clear signal from the United States. Now, with the Copenhagen talks set to begin, the outcome once again hinges on what the U.S. is prepared to do.

On the eve of the Copenhagen conference, a group of scientists has issued an update on the 2007 report of the Intergovernmental Panel on Climate Change. Their conclusions? Ice at both poles is melting faster than predicted, the claims of recent global cooling are wrong, and world leaders must act fast if steep temperature rises are to be avoided.

For months, hopes that a climate treaty would be signed at the upcoming Copenhagen conference have been raised, then dashed, then raised again. Now, with prospects waning that a binding accord on reducing greenhouse gas emissions can be reached this year, ten environmental leaders and climate experts outline for Yale Environment 360 what they believe can still be accomplished at Copenhagen.

Even as the climate science becomes more definitive, polls show that public concern in the United States about global warming has been declining. What will it take to rally Americans behind the need to take strong action on cutting carbon emissions?

Long a ubiquitous part of modern life, plastics are now in everything from diapers to water bottles to cell phones. But given the proven health threats of some plastics — as well as the enormous environmental costs — the time has come for the U.S. to pass a comprehensive plastics control law.

The solar power boom in Germany, Spain, and parts of the United States has been fueled by government subsidies. But now some U.S. states — led by New Jersey, of all places — are pioneering a different approach: issuing tradable credits that can be sold on the open market. So far, the results have been promising.

With skepticism growing about the chances of reaching a climate agreement next month in Copenhagen, Rajendra Pachauri, chairman of the Intergovernmental Panel on Climate Change, says he is “cautiously optimistic” that a treaty can still be signed. But in an interview with Yale Environment 360, Pachauri says the global community may have to move ahead without any commitment from the United States.

Interfering with the Earth’s climate system to counteract global warming is a controversial concept. But in an interview with Yale Environment 360, climate scientist Ken Caldeira talks about why he believes the world needs to better understand which geoengineering schemes might work and which are fantasy — or worse.

Amid a growing call for reducing atmospheric concentrations of CO2 to 350 parts per million, a group of economists maintains that striving to meet that target is a smart investment — and the best insurance policy humanity could buy.

It has been more than 30 years since a groundbreaking book predicted that if growth continued unchecked, the Earth’s ecological systems would be overwhelmed within a century. The latest study from an international team of scientists should serve as an eleventh-hour warning that cannot be ignored.

The Earth has nine biophysical thresholds beyond which it cannot be pushed without disastrous consequences, the authors of a new paper in the journal Nature report. Ominously, these scientists say, we have already moved past three of these tipping points.