(Adds political context)
By Timothy Gardner and Amanda Becker
Aug 18 (Reuters) - U.S. Democratic presidential candidateHillary Clinton on Tuesday staked out her opposition to Arcticoil exploration, putting her at odds with the Obamaadministration one day after it approved drilling off Alaska.
"The Arctic is a unique treasure," Clinton said in a Twitterpost. "Given what we know, it's not worth the risk of drilling."
On Monday, the Obama administration gave Royal Dutch ShellPLC final approval to resume drilling into the oil zoneoff northern Alaska for the first time since 2012.
The decision on Monday drew widespread condemnation fromenvironmentalists, although some experts said President BarackObama had little power to stop Shell from exploring because ithad obtained leases during the administration of formerRepublican President George W. Bush.
Clinton's comment marks one of her most significant breakswith fellow Democrat Obama on a major environmental issue, andappears to be part of a recent effort to appease greens withinthe party whose enthusiasm and support she will need to securethe nomination.
Clinton has also praised the administration's clean powerplant rules as "visionary" but has yet to unveil a comprehensiveclimate platform.
Clinton said if she becomes president, she would seek tophase out fossil fuel extraction and increase fees on companiesoperating on public lands in a way that does not disrupt theeconomy. But she has been careful not to commenton whether she would approve the Keystone XL oil pipeline fromCanada ahead of an expected ruling by the Obama administration.
Clinton's liberal challenger, U.S. Senator Bernie Sanders ofVermont, a socialist, vociferously opposes the pipeline. In May,Sanders was among a among a group of senators who sent theadministration a letter opposing Arctic drilling.
Environmentalists oppose Arctic drilling, saying any spillwould harm walruses, whales, and polar bears in a regionscientists say is already vulnerable to climate change.
The Arctic contains 20 percent of the world's undiscoveredoil and gas, the U.S. government estimates, making it a covetedresource.
Shell suffered a series of mishaps in 2012 in the Arctic,including losing control of an oil rig from which Coast Guarddivers dropped from helicopters had to rescue 18 crew members.But the company says Arctic oil, which would not be produced forat least a decade, is needed to meet growing global demand. (Reporting by Emily Stephenson, Amanda Becker and TimothyGardner; Editing by Lisa Lambert, Caren Bohan and MargueritaChoy)
