CHARLOTTE, N.C. -- The Democratic National Convention formally opens here today -- President Obama's best opportunity until next month's candidate debates to respond to all the heavy artillery Mitt Romney and Republicans fired at him during their convention last week.

Many of the Democrats' attack lines are already well-known. But less clear is what the president will say about energy and environmental issues when he speaks Thursday night -- and how extensively he'll talk about them.

Obama in recent days has been more aggressive than ever about delineating his positions on energy from Romney's.

Speaking at a campaign rally in Toledo yesterday, he said, "Now, Ohio, you can choose an energy plan like the other guy is offering that's written by and for the oil companies. Or you can choose an all-of-the-above strategy for American energy, which means we drill for more oil, we mine for more coal. But it also means that we're going after the new energy sources of the future.

"Now, my opponent said renewable energy sources are 'imaginary.' The folks here in Toledo manufacturing solar panels might disagree with that. These jobs aren't a 'fad' -- they're not imaginary. They're our future."

But in the wake of Romney's crack about global warming during his acceptance speech in Tampa, Fla., last week, a consensus is emerging in Charlotte that Obama should address the issue of climate change more forcefully than he may have originally planned (Greenwire, Aug. 31).

"It's something we all ought to be sensitive about and talking about," said Honolulu City Councilwoman Tulsi Gabbard (D), who is the overwhelming favorite to win an open congressional seat in Hawaii this November.

Gabbard said that coming from Hawaii, Obama is uniquely equipped to talk about the potential ravages of global warming -- especially rising oceans. But she conceded that she could not assess the political wisdom of Obama and his surrogates' talking at length about climate change and energy this week.

Romney's jab about Obama's promise to lower sea levels and heal the planet was roundly condemned by Democrats and their allies in the environmental movement. The Obama campaign sent an email to supporters that said, "It is nothing short of terrifying to imagine a party that mocks climate change taking back the White House."

Speaking to a breakfast this morning sponsored by The Washington Post, House Natural Resources ranking member Ed Markey (D-Mass.) noted that an iceberg the size of Manhattan recently broke off and that all the delegates to the Republican convention could fit on it.

"We could call it Denier Island," he joked.

But despite such fighting words, the twin issues of energy and the environment are fraught with potential political peril for Obama and the Democrats, both this week and in the campaign's final two months. Unlike Romney and other Republican leaders, who are nearly united on the need to further develop fossil fuels as their primary energy strategy, Democrats take a more fractured, regional approach (see related story).

Democratic elected officials in oil-rich states continue to promote more drilling; one of the biggest Democratic advocates for the oil industry, Louisiana Sen. Mary Landrieu, was with Obama for part of the day yesterday, giving the president a tour of her hurricane-ravaged state. Coal is still king among Democratic politicians in Appalachia and other mining centers, and most are highly critical of U.S. EPA under Obama. The issue of hydraulic fracturing has confounded Democrats of all political persuasions. And while Obama has so far resisted approving the proposed Keystone XL oil pipeline, many Democrats -- including some of his allies in the labor movement -- support it.

It's perhaps no coincidence that several speakers at the GOP convention took swipes at Obama's energy and regulatory policies, while it is unclear whether any of the speakers on the docket in Charlotte this week -- with the possible exception of Interior Secretary Ken Salazar -- will take much time defending them.

'It depends on how you talk about it'

Pushing a renewable energy strategy has served Democrats well up to a point, particularly in the swing state of Iowa, where support is strong for extending the production tax credit for wind energy -- an issue Democrats continue to hammer.

"I think 7,000 jobs in Iowa are tied to the wind production energy industry, and Mitt Romney says, 'You know, they're not important; we should just let them go,'" Rep. Debbie Wasserman Schultz of Florida, the chairwoman of the Democratic National Committee, said in an interview yesterday.

Wasserman Schultz also accused the GOP of ignoring the financial potential of solar energy, which she said could become a political talking point in a swing state like Florida and in Arizona, a state Republicans have traditionally won in presidential years but where Democrats sense opportunity.

"If you elect a president like Mitt Romney, he thinks we should only focus on fossil fuels and drilling for more oil and natural gas ... that's not very forward-thinking," she said.

Still, any discussion of alternative energy may inevitably lead to discussion about Solyndra, the bankrupt solar company that wasted a $535 million Energy Department loan -- a favorite attack line of Republicans. Democrats continue to defend the loan guarantee program that provided funding to Solyndra.

"That program was started under President Bush, and it was a program that we knew had some risk," Wasserman Schultz said. "When you're investing in new kinds of industries, there's going to be some risk. ... But there are many more successes than failures in that program, and again, it's important to make those kinds of investments so we can create jobs and so we can have a forward-thinking, impactful energy policy and ensures we don't have to be dependent on our enemies for our energy needs."

But that's an awfully long explanation for a convention speech -- let alone a debate or TV commercial sound bite.

Man-made climate change is another difficult issue for Democrats to talk about directly. The cap-and-trade bill that passed the Democratic House with Obama's support in 2009, only to stall in the Senate, has been demonized by Republicans and many of their business allies as a tax and a jobs-killer, and polls have shown that there is not an overwhelming consensus on the question of whether humans are responsible for climate change.

So Democrats have to walk a rhetorical tightrope. "It depends on how you talk about it," Sen. Ron Wyden (Ore.), who is expected to be the top Democrat on the Senate Energy and Natural Resources Committee in 2013, said today at a panel sponsored by National Journal and The Atlantic.

Anna Aurilio, director of the Washington, D.C., office for Environment America, said that regardless of whether and how Obama and other convention speakers discuss global warming, the Obama administration has several accomplishments to tout on the climate front.

"I'm going to make sure we're appropriately celebrating" those achievements this week, she said, calling the new fuel standards for motor vehicles that Obama pushed through "historic, something that took decades to do."

Markey predicted that the time is close when moderate Republicans will be turned off by what he characterized as the anti-science rhetoric emanating from the GOP convention and will abandon their party for good.

Norman Mineta, a former Transportation and Commerce secretary and ex-congressman from California, said Obama can take political advantage of Republican rhetoric and votes in Congress.

"The whole issue of energy and the environment are issues that we have to work with and stay on top of, and not treat as some looney-tune idea that some people have," he said.

Reporters John McArdle and Noelle Straub contributed.