Although the US has less than 5% of the world's population, we produce 20% of the world's greenhouse gases. We possess the ability to cut emissions in half - eliminating 10% of the world's total greenhouse gases and setting the standard for other nations.
Today's CO2 levels are twice as high as any time in the last 500,000 years and are climbing fast.

CO2 Rise280px-2000_Year_Temperature_Comparison
Source: Intergovernmental Panel on Climate Change

The impacts of global warming can be wide ranging if we do not change quickly.

Fact: Alaska's average temperature has already risen 4 degrees. Alaska's permafrost is melting and it's indigenous population's lives are threatened from threats to their food supply.

Fact: The arctic ice pack that reflects the sun's heat back into space is already 10% smaller and 40% thinner than in 1980. Polar bears have become endangered as the ice pack shrinks, forcing them to swim untenable distances.

Fact: Glacier National Park will have no more glaciers in 20 years.

Fact: Sea levels have already risen 4 to 8 inches. The EPA says "sea level is rising more rapidly along the U.S. coast than worldwide, and along the Gulf and Atlantic coasts, a one foot (30 cm) rise in sea level is possible by 2050. Thousands of square miles of Florida, the Carolinas and the Gulf Coast will be flooded. Large areas of low-lying countries like Bangladesh, parts of China and small islands in the Pacific will be inundated.

Using Half can help slow global warming while improving our economy

McKinsey's landmark "supply curve" chart below shows the cost of reducing greenhouse gases on the vertical axis and how much CO2 is reduced from using each technology. Items above the line cost more than what we do today. Items below the line (on the left) save money.

Greenhouse Supply Curve
Source: McKinsey & Co.

All energy saving technologies are "below the line" - costing less than business as usual. Alternative energy technologies are above the line because they cost more than what we do today.

While alternative energy costs decline in the future, we can drastically cut greenhouse gases and improve our economy today by deploying technologies that help us use half.