Additional drilling for oil and natural gas in the United States may not significantly increase U.S. greenhouse gas emissions or undermine its position at the U.N. climate change conference, energy experts say.

Moving ahead on oil and gas production created little concern for some policy experts, even though the combustion of fossil fuels, such as gasoline and diesel to power cars and generate electricity, has been a major contributor to greenhouse gas emissions.

"Growing U.S. oil production does not necessarily increase global GHG [greenhouse gas] emissions," said John Graham, dean of School of Public and Environmental Affairs at Indiana University. "GHG emissions are determined more by patterns of consumption than by location of production."

New technology and detection of shale energy have allowed the United States to secure energy supplies and put the country on pace to become the largest global oil producer by 2020. EIA statistics revealed that U.S. September crude oil production averaged almost 6.5 million barrels per day, reaching the highest level since 1998.

While Willis Bush, spokesman of American Petroleum Institute, said that the United States consumed the vast majority of the oil the country produced and refined, Graham said the projected slow economic growth and a shift from coal to natural gas for electricity generation might slow demand and reduce carbon emissions.

However, high fossil fuel production remains a critical issue for environmentalists even though U.S. emissions went down because of a dip in the economy.

"We can't let them sell that carbon into the economy," said Kert Davies, research director at Greenpeace. "The world oil, gas and coal reserves they intend to drill have five times as much carbon underground as the atmosphere can take."

How much greenhouse gas would be generated from active oil and gas production by 2020 remains unclear but U.S. energy-related carbon dioxide emissions by 2020 are estimated to increase to 6,931 million teragrams of CO2 equivalent, about 9.7 percent up from 2012 levels and exceeding 2010 levels by 25.2 percent, a U.S. State Department projection report said.

In his first news conference after being re-elected, U.S. President Barack Obama reiterated the urgency to address climate change. He is working to cut greenhouse gases 17 percent by 2020 in the United States, which never ratified Kyoto Protocol, the only international legal binding agreement on curbing greenhouse gases.

Despite pessimism over reaching Kyoto temperature targets, experts say the 17 percent gases cut is achievable.

Besides progress in encouraging fuel efficiency for vehicles and replacing coal for power plants, the Obama administration also doubled use of renewable power.

But environmental groups remain skeptical as fossil fuels dominate energy consumption. They slammed the president's failure to remove fossil fuels subsidies and said it would undermine the climate talks.

"These energy subsidies are completely out of step with a nation that now broadly accepts the need to end our collective oil addiction and fight global warming," Oil Change International, an environmental activists group in Washington, said.

Advocates at the Natural Resources Defense Council, a pro-environment group, Tuesday pressured the Environmental Protection Agency to set new standards for existing power plants. The proposal asserted that the United States could achieve a dramatic emission reduction from the existing power plants that account for 40 percent of the nation's carbon pollution.

"The president put climate change on the national agenda and NRDC's plan shows how the United States can make big reductions in carbon pollution that drive climate change," said Dan Lashof, NRDC's director of climate and clean air programs and a principal author of the proposal.

Experts say although there remains much to be done, the actions in place will give the United States credibility in U.N. climate talks.

"The USA, with CAFE [Corporate Average Fuel Economy] reform, shale gas, and new rules on coal plants will be in a much stronger position relative to EU action on GHG policy," Graham said.