The third presidential debate on Monday night will be foreign-policy themed — and, according to moderator Bob Schieffer, will mostly focus on the Middle East. There will be questions about Iran, Pakistan, terrorism, and perhaps some time for Barack Obama and Mitt Romney to discuss China's role in the world.

The USS New Hampshire conducting exercises in the Arctic Ocean, north of Alaska’s Prudhoe Bay. (Lucas Jackson/Reuters)

Fair enough. Those are all good topics. But a few key issues seem to have been quietly shouldered aside. Europe's still-smoldering debt crisis is a glaring omission. And, curiously, there don't seem to be any plans to discuss energy — a major foreign policy issue that has largely been neglected throughout the campaign.

Last week, Secretary of State Hillary Clinton gave an energy-focused address where she argued, "Energy will be one of the profound issues shaping the 21st century, and we are changing our foreign policy to reflect that.” That sounds like a big deal. It's doubtful that tonight's debate will dwell on this shift, but if Schieffer did want to steer the conversation toward energy, here are five things he could ask about:

1) Climate change, and what to do about it. There have been a whole slew of reports in recent years about how global warming could pose a security threat to the United States. The Pentagon even highlighted climate change in its 2010 defense review. There's the possibility that droughts, floods and water shortages could destabilize key regions, for one. It's still unclear how this will all transpire (here's a more skeptical take on the prospect of "global warring" that I wrote a few years ago), but they're on the minds of plenty of foreign-policy analysts.

So what do we do about it? And does either candidate have any ideas about how to revive global talks on curbing greenhouse-gas emissions, which made slight progress in Durban last winter but have otherwise stalled out?

2) If North America is set to become a major oil producer, how does that affect U.S. foreign policy? U.S. oil imports have been shrinking during the Obama years, thanks to booming crude production in places like North Dakota and rising fuel efficiency. Romney, meanwhile, is vowing to push for "North American energy independence" by 2020. It's not clear that he can achieve this, but let's give him the benefit of the doubt for a second.

If North America does become a major world oil producer and manages to shrink its imports, would that change U.S. foreign policy at all? Plenty of experts have argued that the U.S. economy will still be vulnerable to turmoil in the Middle East for years to come, that there's no way to detach ourselves from the global oil markets even if we did become energy independent. But what do the candidates think about this?

3) The Arctic is melting. What happens next? This summer, the extent of Arctic sea ice reached its lowest level on record. As the planet warms and the ice recedes, countries like Russia, China, Norway, Denmark and the United States are rushing into newly uncovered waters, angling for oil and gas resources and staking out territory.

The State Department is already worried about conflicts that could stem from this free-for-all. “The Arctic is a frontier of oil and gas—and also a potential catastrophe," Clinton said in her speech Thursday. "It’s critical we act now to set the rules of the road.” So what do Obama and Romney think?

4) Biofuels policies are driving up global food prices. Should they be repealed? After a massive drought parched the Midwestern United States this year, global food prices have been soaring. That could plausibly turn into a global crisis, seeing as how high food prices led to riots around the world in 2008 and arguably contributed to the Arab Spring protests in 2011.

As various experts have noted, biofuels policies in the United States and Europe have helped push up world food prices. Up to 40 percent of the U.S. corn harvest this year will go toward making ethanol. Is that a trade-off worth making? Or is it time to rethink our biofuels laws?

5) What sorts of energy infrastructure should we be exporting to the rest of the world? Over at the National Journal, Coral Davenport points out that the United States will be heavily involved in helping China, India and even Europe develop new sources of energy in the decades to come. The State Department, for instance, is already enmeshed in efforts to help Europe reduce its reliance on Russia's natural gas. 

Clinton discussed a related issue in her energy speech on Thursday: "1.3 billion people don’t have access to energy," she said. "We have the technology and know-how that can help people leapfrog to energy that is reliable and affordable but also clean and efficient.”

But U.S. policy on this front is often contradictory. Over at Climate Progress, Justin Guay has a post noting that the U.S. Overseas Private Investment Corporation (OPIC) has been working at cross-purposes with the U.S. Export-Import Bank: The former has been focused on promoting renewable energy abroad, while the latter has focused on heavily polluting (albeit cheaper) coal. So what should be the overarching goals for these efforts?

That's probably all way too much ground to cover in a 90-minute debate. But even a question or two could be quite illuminating.

Further reading:

—Coral Davenport has a longer look at how energy has become a global issue.

—How climate change disappeared from the debates.

Update: Michael Levi has his own set of energy questions to ask. Very much worth reading.