China and the U.S. combine to spew a whopping 43 percent of global emissions of greenhouse gases, so it's no surprise that presidents Obama and Hu will spew a bit more CO2 talking about climate change and energy during the state visit this week. It's the latter that's responsible for the two countries' outsized emissions: China meets roughly 70 percent of all its energy needs by burning coal while the U.S. guzzles oil, consuming some 10 million barrels a day even during the depth of the Great Recession in 2009.

The Chinese are catching up in that department, thanks to a burgeoning love affair with cars. But the Chinese are also keen to do something about climate change, despite their negotiators snubbing of President Obama in Copenhagen in 2009. In fact, Chinese flexibility helped pave the way for compromise during international climate change negotiations in Cancun this past December.

The U.S., of course, most likely will not do much about climate change legislatively in the next few years, unless Republican politicians have a conversion experience in the wake of weird weather. But Obama's executive branch alone can and will do a lot—from new auto efficiency standards to mandated energy savings plans from all government agencies, including the military. And the Environmental Protection Agency is slowly but surely moving to regulate greenhouse gas emissions from power plants.

China is arguably doing more. The country has committed to reduce the CO2 emissions associated with every economic unit produced—so-called carbon intensity—by at least 40 percent by 2020—and has pledged to make clean energy targets mandatory. At the same time, China's economy continues to develop at an unprecedented pace. Electricity demand is a proxy for that: China used more than 4.2 trillion kilowatt-hours of electricity last year, 80 percent of which came from burning coal.

Changing that is a key focus for U.S. and Chinese cooperation, hence the no less than three efforts to advance carbon capture and storage technology for coal-fired power plants that came out of the previous meeting between the two Presidents in Beijing in 2009. And the U.S. is already benefiting from the "China price" on solar photovoltaics, among other clean energy technologies. That may not be good for manufacturing jobs in the U.S.—Evergreen Solar recently defected to China—but it is good for speeding the adoption of energy technologies that do not produce CO2.

At the same time, the U.S. can benefit from China's breakneck pace to advance what they call "new energy"—wind and solar power but also nuclear, all of which do not emit much CO2. Carbon capture and storage demonstration projects can happen much faster in the Middle Kingdom while any American nuclear renaissance would benefit from the experience gained from the Chinese nuclear boom.

Of course, there is competition among the two countries on the energy front—from Secretary of Energy Steven Chu's warnings of a "Sputnik moment" to rare earths and other resources diplomacy. The U.S. is even accusing China of unfair trade practices thanks to its subsidies for clean energy technologies and has banned the U.S. military from buying solar panels stamped "Made in China."

But cooperation and competition can and do happen side by side—just remember U.S. grain exports to the U.S.S.R. during the Cold War. In fact, the last time Hu and Obama met, they set out a shared agenda on clean energy partnership: three Clean Energy Research Centers focused on energy efficiency, "clean coal," and electric vehicles as well as an effort to see if fracking for natural gas could help wean China off coal. These centers are now expected to lay out their plans for joint work as part of this week's summit. Let's hope those plans are ambitious.

Image: President Barack Obama holds a bilateral meeting with President Hu Jintao of China at the Grand Hyatt Hotel in Seoul, South Korea, November 11, 2010. (Official White House Photo by Samantha Appleton)