President Obama's newest adviser, John Podesta, will reportedly push the White House to focus more heavily on climate change in the coming year. Podesta is coming from the Center for American Progress, a liberal think tank that put a heavy focus on climate policy.

John Podesta, president and chief executive of the Center for American Progress Action Fund, speaks at the National Clean Energy Summit 2.0 in Las Vegas on Aug. 10, 2009.  (Eric Jamison/Associated Press)

That's according to my colleague Greg Sargent, who cites a Politico report on Podesta's new role: "With chances of major legislation on climate change all but dead given congressional opposition, Podesta will push for aggressive executive action, in addition to backstopping new Environmental Protection Agency chief Gina McCarthy on controversial new emissions guidelines for power plants."

(Podesta will, however, recuse himself from any decision to approve or deny the Keystone XL pipeline across the Canadian border, which the White House is still mulling.)

So what might this "aggressive executive action" look like, exactly? Let's start by recalling that the Obama administration is already pursuing a number of steps to tackle climate change without the help of Congress. The ostensible goal is to cut greenhouse-gas emissions 17 percent below 2005 levels by 2020, and the list includes:

-- The Environmental Protection Agency recently issued standards that will make it virtually impossible to build any new coal-fired power plants that can't capture and store their own emissions. Next June, the EPA will propose further rules to reduce emissions from the thousands of existing power plants around the country.

-- The White House is hammering out an agreement with China and other countries to phase out hydrofluorocarbons (HFCs), a potent greenhouse gas used in everything from soda machines to many car air conditioners.

-- The administration is developing a plan to curtail methane emissions from natural-gas production.

-- The Energy Department is ratcheting up efficiency standards for appliances and buildings. The Interior Department will try to speed up wind and solar development on public lands.

-- Federal agencies have been ordered to get 20 percent of their electricity from solar, wind, and hydropower by 2020.

The caveat? It's still not entirely clear how effective all of these policies will be. Some of that is up to the White House, and Podesta's presence in pushing for stronger action could tilt the scales here.

For example: The EPA is weighing various approaches for regulating existing coal- and gas-fired power plants, which are responsible for nearly one-third of the country's greenhouse-gas emissions. The EPA could opt for a light touch here — requiring plants to adopt small efficiency upgrades — or enact more sweeping rules that push for bigger emission cuts.

And Podesta may well have other ideas for executive action. Back in 2010, after Republicans took back the House, Obama's agenda appeared moribund. So Podesta's Center for American Progress put out a big policy paper (pdf) laying out a wide array of further steps that the White House could take, on its own, to cut U.S. greenhouse gas emissions. Some more ideas, from the paper:

-- Even more EPA pollution rules: The paper called on the White House to push the EPA to regulate various other pollutants from coal-fired power plants, from mercury pollution to coal ash waste. Most of these steps the Obama administration has already taken, except for the rules on coal ash, which are still in limbo.

-- A fee on oil imports: The paper noted that the president had the authority under the Omnibus Trade and Competitiveness Act of 1988 to "levy a fee on imported oil," provided that the secretary of commerce and secretary of defense "determine that continued high rates of oil imports threaten to impair national security."

-- Upgrade the federal vehicle fleet: "Issue an executive order to require the U.S. General Services Administration to double the percentage of the federal transportation fleet that uses non-oil-based fuel by 2015. All other federal vehicles purchased should attain fuel economy standards 15 percent higher than the average vehicle in that class."

-- Upgrade urban buses. "Instruct the Environmental Protection Agency to implement Section 219 of the Clean Air Act, which requires bus fleets in metropolitan areas with more than 750,000 people (as of 1980) to have buses powered by 'lowpolluting fuel,' defined as 'methanol, ethanol, propane, or natural gas, or any comparably low-polluting fuel.'"

-- Promote clean energy within the military. "Establish a pilot program to retrofit a small number of Air Force hangars at high solar-potential bases, using Hangar 25 as a model and employing the latest efficiency measures."

Now, it's unclear whether the Obama administration will take up any these suggestions. (In particular, a "fee on imported oil" sounds like a tough sell at a time when U.S. oil imports are already dropping rapidly.) And the White House is hardly free of constraints here — if the EPA gets too creative with its carbon regulations, for instance, the courts could well strike them down. Plus, future presidents can always overturn these executive actions.

Even so, in his forward to the paper, Podesta insisted that the White House should use as much of its executive authority as possible. "The ability of President Obama to accomplish important change through these powers should not be underestimated," he wrote. "Congressional gridlock does not mean the federal government stands still."

Further reading:

-- A more complete breakdown of Obama's climate plan.

-- Obama’s climate plan could cut power-plant emissions 26 percent. Or just 1 percent. There's a lot of leeway here.