Presidential candidates Hillary Clinton, Donald Trump and Bernie Sanders disagree widely about climate change, energy and environmental issues. Composite image of UPI photos

WASHINGTON, June 6 (UPI) -- Some of the issues being debated in the 2016 presidential campaign start with a generally accepted premise from Hillary Clinton, Bernie Sanders and Donald Trump.

Climate change is not one of them.


Clinton and Sanders believe the science showing the planet is warming due to pollution created by humans, and the gradually warming temperatures are causing dramatic shifts in climate and weather across the world with potentially devastating consequences.

Trump, like many Republicans, is deeply skeptical of that science and believes the climate change "crisis" Democrats decry is really a political ploy to offer justification for more taxes and regulations on oil and gas companies they already do not like.

Here is a look at where the candidates stand on the issues of climate change, energy and two related, hot-button issues: the Keystone XL pipeline and the natural gas extraction process known as hydraulic fracturing, or fracking.


Climate change

Clinton and Sanders essentially agree with Democratic orthodoxy, backed by international scientists, that climate change is a real phenomenon, and is being accelerated due to the amount of pollution humans generate that is vented into the atmosphere.

Clinton terms it "an urgent threat and a defining challenge of our time."

Sanders describes the issue in equally stark terms: "Climate change is the single greatest threat facing our planet. The debate is over, and the scientific jury is in: global climate change is real."

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Not according to Trump, who has called it a "hoax" on multiple occasions. Trump maintains the issue is one Democrats have put forth to help advance their anti-business, pro-tax agenda.

The fact-checking group Politifact found numerous instances of Trump referring to climate change as a hoax, including on Twitter and in media interviews.

Clinton and Sanders have each proposed specific policy changes to address climate change.

Clinton has pledged to reduce the nation's carbon emissions by 30 percent in 10 years, relative to pollution levels in 2005. She has also proposed expanding federal programs to reduce energy inefficiency in homes and public buildings like schools and hospitals.

Sanders has taken aim at oil and gas lobbyists who he says spend millions on campaign contributions to buy influence over energy and environmental legislation in Congress.

Sanders said he will ban all oil and gas lobbyists from working in his administration and has called for the reversal of Citizens United, the controversial Supreme Court decision that legalized unlimited campaign spending by corporations to outside groups known as super PACs.


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Both candidates support the Paris Climate Agreement negotiated by President Barack Obama, with 177 nations, aimed at reducing global air pollution.

Where Clinton and Sanders see the need for greater regulation and government action, Trump sees job-killing rules that hurt American businesses.

In a policy speech in May, Trump released his "America First Energy Plan," which he touted as the antidote to Clinton's "poverty expansion plan."

Trump proposes opening up more land for oil and natural gas exploration including on federal land, echoing past Republican calls to "drill, baby, drill."

Trump has pledged to undo Obama's executive orders related to climate change, which have severely restricted coal-fired power plants and enforced stricter emissions standards for U.S. automakers.

Trump has also pledged to "rip up" the Paris Climate Agreement.

Energy

On the question of energy production, Clinton and Sanders both advocate a shift toward renewable sources of energy with specific policy proposals.

Trump, on the other hand, wants to reduce regulations on fossil fuel companies, arguing they are the fastest way to make American energy independent. Trump said in his energy speech the economic benefits and reduced reliance on foreign oil far outweigh any potential environmental problems.


Clinton has set a goal of installing 500 million solar panels in the United States over the next decade and has called for enough renewable energy production to power every American home by the middle of this century.

Sanders also has placed heavy emphasis on replacing fossil fuels with renewable energy, calling for a "100 percent clean energy system" that excludes fossil fuels and nuclear power.

He says funding for the transition to clean energy should come from closing tax loopholes benefiting oil and gas companies and replace it with a tax on carbon emissions, which he says will force cost-conscious businesses to cut down on excess pollution.

Trump has said he will restore U.S. coal production, which has been hit badly by federal regulations on high-polluting coal-fired power plants.

The contrast was highlighted by Clinton's pledge to put coal mines "out of business" -- a remark Trump seized on as evidence Clinton is more concerned about her environmental agenda than American workers.


Keystone XL pipeline

The proposal for a massive, 1,200-mile pipe to ship light crude oil stretching from the tar sands in Alberta, Canada, south, across the U.S. plains to American refineries on the Gulf of Mexico generated years of political controversy.

After six years of environmental review, the Obama administration rejected the proposal by the Canadian oil company TransCanada in 2015.

Keystone was the single largest point of contention between Clinton and Sanders on environmental issues. Sanders opposed Keystone from the outset, while Clinton hedged on the issue for months, saying she wanted to read the multi-agency review of the proposal before making her decision.

Once the Obama administration finally rejected the proposal, Clinton did as well. Sanders criticized Clinton's late decision, saying it was evidence she was in debt to oil companies who have made donations to her campaign's super PAC.

Trump has also taken a nuanced position on the Keystone XL pipeline. He has said he would ask TransCanada to renew its permit application and would consider authorizing the request, provided TransCanada would share the profits with American communities where the pipeline runs.

TransCanada rejected that proposal, saying additional financial outlays would make the project cost-prohibitive.


Fracking

Another hot-button environmental issue divides the candidates: natural gas hydraulic fracturing, or fracking.

The process entails jagged pipes being inserted into natural gas-rich shale formations, primarily in West Virginia, Pennsylvania, Ohio and New York. Water mixed with chemicals is shot through the pipes, releasing the natural gas for collection.

Critics say the process endangers underground water tables and the chemicals involved create hazardous waste that cannot be properly treated and could harm drilling areas if spilled.

Proponents say the drilling process is safe and could unleash America's vastly untapped natural gas reserves, creating a supply of clean-burning fuel that is better for the environment than fossil fuels.

Trump is on record supporting fracking and said the industry could create 2 million jobs in seven years if restrictions are lifted.

Clinton has not proposed the outright ban on fracking advocated by Sanders and others on the left. She does, however, propose a number of restrictions, including retaining the ban on fracking on federal land, and in communities and states where laws are on the books banning the practice.

"By the time we get through all of my conditions, I do not think there will be many places in America where fracking will continue to take place," Clinton said.