Measure.In the midst of the fight of our lives (the House floor debate on the American Clean Energy and Security Act), a coalition of major U.S. groups called for the Obama Administration to outline its “yardstick” on global warming. What is it that this “scientific and pragmatic” Administration will use to measure our efforts to solve global warming pollution — its yardstick?

Well the CEOs of 47 U.S. organizations, representing environment, faith, development, and youth groups have an answer. As the letter from these groups to the Obama Administration says:

“We are writing to urge you to work with other world leaders at the upcoming G8 Summit to set a strong science-based goal for reductions in emissions of greenhouse gases aimed at keeping the increase of global average surface temperature, compared to pre-industrial levels, as far below 2 degrees Celsius/3.6 degrees Fahrenheit as possible.”

The “two degrees” threshold is a pretty important yardstick. The impacts of global warming will be potentially severe in a number of regions around the world, including the US, if we cross this threshold.

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And it isn’t like these groups made up this “yardstick”. After all, it is the goal called for in the:

Having a clear measure against which to judge progress will be central to ensuring that the American public continues to be bought into solving global warming. After all, the American people generally have a “can do” attitude. Once we fully get to grips with the problem, we want to solve it — not half way, but all the way.

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So that is why having such an overarching “yardstick” as holding global temperatures to below a certain threshold is so critical — it frames why we are working to solve global warming. It will frame how we judge whether or not we are heading in the right direction or whether we need to do more.

Where President Obama stands on “two degrees” will be a consistent question when he attends the Group of Eight (G8) meeting in early July. Ambiguity breeds mistrust and on global warming the U.S. has had a lot of goodwill destroyed over the last 8 years — thanks to the efforts of the “unnamed Administration”. The Obama Administration and now the House of Representatives have made serious efforts to rebuild international trust on global warming. But not providing clarity on “two degrees” spurs mistrust as evidenced in a recent Reuters story about the Obama Administration not wanting to reference the 2 degrees Celsius objective in the G8 statement.

So the letter from these 47 groups to President Obama as he is just about to embark on his G8 trip provides a simple recommendation — embrace 2 degrees Celsius (3.6 degress Fahrenheit) as the U.S. yardstick on global warming. Don’t be separate from it any longer. Taking it as your own will help spur the U.S. public to action and build a huge amount international goodwill.

Coming out in support of this “yardstick” is a small, but hugely important signal to the American people and the world that we are truly committed to solving global warming.