WASHINGTON (AP) -- Democratic presidential candidate Bernie Sanders calls climate change the greatest threat to national security. Front-runner Hillary Rodham Clinton promises to install more than 500 million solar panels across the country.
On the Republican side, Jeb Bush would phase out tax credits for solar power. Rival Marco Rubio wants to cut the federal gas tax by 80 percent.
They're among the stark differences between the two parties on energy and environment issues that underscore the sky-high stakes for both sides of the debate in the 2016 presidential race.
After President Barack Obama's two terms, business and environmental groups see a game-changing election. Many environmental groups and Democrats fear a potential rollback of the Obama administration's policies on climate change and renewable energy under a Republican president. Business groups and Republicans are eager to boost oil and gas production following years of frustration with Obama.
"At the end of the day, there's a clear choice for all" of the candidates, said Tom Pyle of the pro-business American Energy Alliance. "Either continue the Obama administration's anti-energy agenda or chart a new course that promotes affordable and reliable energy for all Americans."
"Everywhere you look, from New York's Wall Street to Iowa's Main Street, voters are ready for real climate action and the clean energy revolution," countered Khalid Pitts of the Sierra Club, "except if you are a Republican running for president."
Some of the issues dividing the candidates in the presidential election:
Obama heads to Paris on Sunday for an international climate conference, and Republicans are united in opposition to a possible pact and the president's plan to cut greenhouse gas emissions from U.S. power plants.
Texas Sen. Ted Cruz and GOP presidential front-runner Donald Trump are among several Republican candidates who reject mainstream climate science. Ben Carson calls himself a "climate science questioner" and says "the temperature of the earth is always fluctuating."
Bush said at a New Hampshire town hall last month that he thinks the climate is changing and that "humans have some say in it for sure." But, he added, "What I don't want to do is destroy the American economy as the solution."
Rubio asserted at a recent GOP debate that "America is not a planet" and said that when it comes to global warming, he was "not going to destroy our economy the way the left-wing government we are under now wants to do."
Republican candidates all warn that Obama's plan to curb greenhouse gas emission from U.S power plants could cost thousands of jobs and raise electricity costs for businesses and families.
Clinton, Sanders and fellow Democrat Martin O'Malley support the president's Clean Power Plan, calling it a legacy-worthy effort to slow climate change.
OIL & GAS DRILLING
Republican candidates all say they would approve the Keystone XL oil pipeline recently rejected by Obama. Democrats support the president's action.
Republicans also agree on lifting the 40-year-old U.S. ban on crude oil exports; Democrats are opposed. Sanders wants to stop all new oil and gas drilling on federal lands, as well as in the Arctic and Atlantic oceans, while Republicans would expand drilling for oil and natural gas.
Like Sanders, Clinton opposes drilling in the fragile Arctic region, which she calls "a unique treasure." But she generally supports drilling on federal lands.
Democrats back federal subsidies for renewable energy such as wind and solar power. On the GOP side, the candidates range from skeptical to hostile about a policy several describe as Washington "picking winners and losers."
Trump has long opposed wind power. He famously objected to a proposed wind farm near a golf course he was building in Scotland.
But as a presidential candidate, his views have evolved. At a recent event in Iowa, one of the nation's top wind-farm states, Trump offered grudging support for a federal tax credit for wind energy. While calling wind turbines "very, very expensive" to build and maintain, Trump said he is "OK" with subsidies.
"I don't think they work without subsidy, which is a problem," he said.
New Jersey Gov. Chris Christie backs credits for wind energy and supports a federal Renewable Fuel Standard that mandates ethanol in gasoline, a policy Cruz has denounced as "corporate welfare." Trump also supports the corn-ethanol mandate, which is hugely popular in early-voting Iowa. Rubio, Bush and Ohio Gov. John Kasich say it should be phased out over time.
"Ultimately, whether it's ethanol or any other alternative fuel ... the markets are going to have to decide this," Bush said.
Democrats back the ethanol mandate as well as incentives for biofuels.
COAL AND NUCLEAR
After running as a champion of coal in 2008, Clinton now calls for protecting health benefits for coal miners and their families and helping retrain them for new jobs. She would use a combination of tax incentives and government grants to help coal-dependent communities repurpose old mine sites and attract new economic investment.
Republicans all support coal production and enthusiastically back nuclear energy; Clinton offers cautious support for nuclear power. Sanders has called for a moratorium on nuclear-plant license renewals and cheered the closure of the aging Vermont Yankee nuclear plant.