What future does the U.S. proposal mean?

The long-awaited American proposal for provisional mitigation targets was finally served up last week, and the dominoes started falling. China immediately followed with their commitment to cut carbon intensity, and India soon thereafter.

The importance of the American mitigation numbers really can’t be overstated, both because we’re far and away the largest per capita emitter of greenhouse gasses and every percentage point represents an enormous, worldchanging (literally) amount of carbon, and because every other nation’s commitments really do hinge on them. If the U.S. commits to greater cuts, so does Australia, Canada, China, India, you name it. America’s rather weak target of a 17% reduction from 2005 levels by 2020 (a mere 3-4% below 1990 levels, the benchmark year used by every other country) sets the stage for a relative lack of ambition throughout. (With a few notable exceptions.)

So what sort of impacts do the current proposals–anchored by the U.S. 3-4% cuts below 1990 levels by 2020–translate to? We can get a pretty good sense with the help of a couple tools and reports.

First stop is the Climate Interactive Scoreboard, which collects all current mitigation proposals, runs the numbers through a finely-tuned simulation (built by MIT researchers and the Sustainability Institute), and spits out the projected global temperature rise by 2100. As things now stand, we’re looking at about a 3.8 degree Celcius (or 6.8 degree Fahrenheit) increase over historic averages, as you can see in the widget below. For some reference, as of 2005, temperatures had already increased by 0.8 degree Celcius, and “business as usual” with no national mitigation efforts would warm the world by 4.8 degrees Celcius by 2100.

Want a second opinion? Another similar tool, the Climate Action Tracker built by the folks at Climate Analytics, puts the projected rise under current proposals at 3.5 degrees Celcius.

It’s important then to remember that back in July, leaders of the world’s 17 largest emitters of greenhouse gasses, including the United States, agreed at the G8 meetings to work together to keep warming under 2 degrees. The contradiction between the rhetorical “shared vision” goals of the planet’s worst climate polluters and their proposed efforts is stark. (And this is before we consider that there’s plenty of evidence that this 2 degree benchmark is already dangerously high.)

What does this 3-4% cut mean for life in America? Things are going to get a lot hotter. A look a recent report, Global Climate Change Impacts in the United States–commissioned by the Bush administration, in fact, and conducted entirely by scientists they selected–shows just how dramatically such a temperature rise would affect the country.

In the Northeast, we’d be looking at about 24 days over 100 degrees Fahrenheit every year by the end of the century. The climate in New Hampshire would resemble that of North Carolina today.

Chicagoans still talk about the great heat wave of 1995, which killed about 600 people. Under the current U.S. proposals, President Obama’s home town would be facing 60 such heat waves every decade. Water levels in Lake Michigan would drop two feet. Illinois would feel like south Texas. How about Los Angeles? L.A. would get a lot hotter and drier, with average temps rising about 8-10 degrees Fahrenheit and spring rains in Southern California–already slight, but crucial to water supplies–would drop about 30-40 percent.

And I’m just skimming the surface of the impacts of a 3.5 degree Celcius rise on our country. When you hear leaders defending America’s positions here in Copenhagen–or the current Congress proposals in Washington, for that matter–take a moment to look over the predicted impacts and think about whether that’s a country you want your children surviving in.