The specter of a military confrontation on the Ukrainian border is stoking fears in Europe of an interruption in natural gas from Russia -- and pumping fresh life into the debate over whether President Joe Biden's climate agenda is brushing up against difficult geopolitical realities.
Critics of the Biden administration say its efforts to curb domestic oil and gas production have complicated its ability to negotiate with Russia, which provides more than a third of Europe's natural gas.
To others, the standoff demonstrates the need for a swift transition to clean energy, "so that we're not held hostage by Russia moving forward," says Erin Sikorsky, director of the Center for Climate and Security and a former intelligence official.
Either way, experts say, the conflict in Eastern Europe is shining a spotlight on the challenges ahead as governments adapt to an evolving energy landscape.
"It is clear that climate change is a huge focus for the Biden White House," said Ben Cahill, a senior fellow at the Center for Strategic and International Studies. "But energy security realities are intervening, and they can't be ignored."
As Russian troops amass along Russia's border with Ukraine, American officials are warning of a possible invasion in the coming days or weeks. In the event of an escalation, Western leaders fear that Russian President Vladimir Putin could halt gas supplies to Europe, potentially threatening Europe's energy security.
The Biden administration has prepared contingency plans to backfill Europe's energy needs in such an event. But oil interests and Republican lawmakers argue that a reduction in domestic fossil fuel extraction in recent years has hamstrung the United States' ability to ensure Europe's energy security.
Frank Macchiarola of the American Petroleum Institute told ABC News that "ongoing tensions between Russia and Ukraine serve as a reminder of the critical role of U.S. oil and natural gas in meeting our nation's energy needs and ensuring our allies have access to a stable supply of affordable, reliable energy."
On Capitol Hill, Sen. Lisa Murkowski, R-Alaska, echoed that sentiment to Politico, characterizing the Biden administration's scramble to shore up natural gas for Europe as "a crisis strategy that didn't have to be."
But many experts disagree with that critique. Because investments in domestic oil production today generally won't impact the market for many years, Biden is limited in what he can do now to boost oil reserves. In the meantime, Cahill said, Biden should continue to advance his clean energy ambitions -- but recognize the need for future U.S. oil production.
"The Biden administration should pursue its climate agenda, including tougher regulations on methane emissions from the oil and gas industry," Cahill said. "But we'll need fossil fuel investment for years to come, even as the energy transition picks up speed."
Sikorsky warns critics not to conflate "the short-term crisis and the long-term strategy."
"The administration has to do what it has to do to make sure energy supplies in Europe remain strong in the face of Russian aggression," Sikorsky said. "But it has do that with an eye toward a more rapid transition to renewable energy."
Because Russia's economy relies so heavily on natural gas exports to Europe, Biden and European allies still have substantial energy-related leverage in negotiations with Moscow. The Russian government generated almost 30% of state revenue in 2020 from fossil fuel companies, including $40 billion in gas sales to Europe, according to one U.S. government report.
"The long-term threat to Russia's market position is actually far greater" than the threat to Europe's energy needs, said Matthew Schmidt, director of the International Affairs program at the University of New Haven. "Russia is a dinosaur. Their economy is weak. It's a carbon-based economy, and if Putin were to use gas a weapon, he's going to kill the market."
Additionally, experts say renewable energy breakthroughs are closer than most leaders realize -- a development that could render oil and gas obsolete in the coming decades.
Schmidt said he would encourage the Biden administration to forego any further investment in fossil foils and instead "go in on clean energy now, because that's the long-term trend."
This week, Biden and German Chancellor Olaf Scholtz pledged to halt production of Europe's Nord Stream 2 pipeline in the event of an invasion. The U.S. and its allies could also directly sanction the Russian oil and gas industry as part of an effort to "reverse the direction of energy leverage," according to a Brookings Institute policy paper.
But sanctions targeting Russia's oil industry carry substantial risks for Europe's energy needs. Enacting them would present the same outcome as Putin preemptively cutting off natural gas.
Cahill said that Biden's quest for additional energy resources "does raise questions about whether we've under-invested in fossil fuels in the past five to seven years ... which in turn raises questions about our ability to impose sanctions."
For some industry experts, Europe's dependence on Russian oil serves as a cautionary tale for the U.S. -- and an impetus for the U.S. to expand investments in clean energy.
"Europe's dependence on fossil fuels has made it vulnerable, the result of investment choices made over the course of decades," said Trevor Higgins, vice president for climate policy at the left-leaning Center for American Progress.
"We should not repeat the same mistakes," said Higgins. "A clean energy economy will be more secure and resilient than continued dependence on fossil fuels."