Global efforts to mitigate climate change are resulting in the most ineffectual diplomacy since U.S. Secretary of State Frank Kellogg and French Foreign Minister Aristide Briand tried to end all war with international law—eleven years before Hitler launched World War II.

The fecklessness of climate diplomacy was on full display last week at the Group of Eight summit of industrialized countries in Italy, where the international community simultaneously vowed to limit global warming and disavowed the necessary action to do so.

During the summit, U.S. President Barack Obama convened a Major Economies Meeting of 17 countries responsible for 80 percent of global greenhouse gas emissions. Together, these countries agreed that they “ought” to limit global warming to 2 degrees Celsius. British Prime Minister Gordon Brown labeled this “historic” and German Chancellor Angela Merkel called it an “important step.” A more apt description of the temperature target is “impossible.” Here’s why.

As a recent study in the scientific journal Nature notes, global greenhouse gas emissions must fall more than 50 percent below 1990 levels by 2050 in order to have a 75 percent chance of limiting warming to 2 degrees Celsius. According to research compiled by the United States Climate Change Science Program (now the Global Change Research Program), a clearinghouse for global warming science conducted by federal agencies, reducing global emissions by 50 percent below 2000 levels by 2050 would require developing countries to reduce per capita greenhouse gas emissions by 62 percent below business as usual, even if developed countries somehow cut greenhouse gases by 100 percent.

Yet the G8 pledged to reduce emissions “only” 80 percent—from an undefined baseline—by 2050. And before the ink was dry on the summit’s climate communiqué, Russian and Canadian officials publically questioned the feasibility of the 80 percent emissions cuts for their countries. Developing countries rejected any limits altogether, refusing to commit to expensive emissions cuts that could jeopardize their number-one priority: poverty reduction.

Clearly, the emissions calculus to reach the 2 degree Celsius target doesn’t add up. But there are three pathways to bridge the gap between rhetoric and reality.

The first is for everyone to quit. Developing countries have a sovereign right not to act on climate change, and their rapidly growing economies will account for the preponderance of future growth in global emissions, which gives developed countries little reason to limit emissions themselves. As Italian Prime Minister Silvio Berlusconi told The New York Times, it makes little sense for the G8 to commit to stringent emissions reductions if “five billion people continue to behave as they have always behaved.” Continued...