Two major reports assessing climate change and its current and future effects on the US and the world have been published in the last few days.

The Arctic Climate Impact Assessment is a comprehensively researched, fully referenced and independently reviewed evaluation of arctic climate change and its impacts. Commissioned by the group of eight nations with arctic territory (including the US) it involved an international effort by hundreds of scientists over four years, and also incorporates the knowledge of indigenous peoples.

The projected impacts in this report are based on observed data and a moderate scenario of future warming, not a worst-case scenario. Compared to the full range of scenarios analyzed by the Intergovernmental Panel on Climate Change (IPCC), the primary scenario used in the ACIA analyses falls below the middle of the IPCC range of projected temperature rise.

The report, available on the website above and well worth the read, highlights ten key findings, the primary one being that the arctic climate is warming more rapidly than the rest of the world, and  with much greater changes to come. The loss of polar ice is projected to accelerate further global warming and to contribute to sea-level rise, flooding, disruption of plant, animal and human habitat and a number of other significant and dangerous consequences.

The Pew Center on Global Climate Change’s Observed Impacts of Global Climate Change in the US, is the twelfth in a series of Pew Center reports examining the impacts of climate change on the U.S. environment.

Unlike the prior reports which dealt with potential impacts, this report argues that ecosystems are already responding to climate change, and draws the linkage to anthropogenic CO₂ emissions.

Both reports stress the need for emissions reductions—not as a way to stop warming, but as a way to slow it, and to mitigate the damage already being done.

Transportation, is, of course, a key contributor to CO₂ emissions, and a good place to look for reduction. A recent paper published in the Proceedings of the National Academy of Sciences (PNAS) (Thanks, Jamais!) outlines several approaches to curbing the carbon deficit, one of them being the doubling of fuel efficiency in vehicles.

A policy to promote hybrid technology in new cars and light trucks would go a long way to doubling fuel efficiency to >40 mpg. Providing economic incentives for high-mileage vehicles could reduce oil imports and would not require cultural changes such as driving fewer miles or pursuing mass transit, two other useful options.

Easier said than done, but the right idea, and the core of the California climate change bill that establishes CO₂ standards for vehicles. (Even that bill didn’t strive for a doubling in fuel efficiency.)

None of this, however, will have much resonance with the current administration.

A wire story from Scripps Howard outlines the reaction to the two reports above.

Mandatory regulation or caps on greenhouse-gas emissions are unlikely for the foreseeable future, White House science adviser John Marburger said in an interview.

“Not in this administration,” he said.

Despite saying the Bush administration would not change its policy on greenhouse-gas emissions, Marburger praised the two new reports.

“I think the present policy is flexible enough to accommodate these existing reports and any recent scientific reports that I am aware of,” Marburger said. “There is general acceptance of the need to decrease the amount of [carbon dioxide] produced in the process of making energy. Exactly how you go about doing that and how much is necessary is not yet understood.” In response to the new reports, Sens. John McCain, R-Ariz., and Joseph Lieberman, D-Conn., renewed their calls to pass bipartisan legislation capping greenhouse-gas emissions.

The Arctic Climate Impact Assessment, conducted and reviewed by nearly 300 scientists, is the most comprehensive evaluation to date of the impact of climate change.

Its release was initially scheduled to be accompanied by a set of policy recommendations, but the Bush administration pressured other nations not to release those recommendations, Sheila Watt-Cloutier, chairwoman of the Inuit Circumpolar Conference, said in Senate testimony.

A less nuanced view of the administration’s perspective on climate change comes during a BBC4 interview with Myron Ebell, director of the Global Warming and International Environmental Policy project at the Competitive Enterprise Institute, and an advisor to the administration. The Ebell bit starts at 3:44 on the clip. Listen and learn.