Six women started climbing the 72-story Shard skyscraper in downtown London to protest the company.
"They don't want us talking about their plan to drill in the Arctic," they said in a statement published before their Thursday ascent. "We're here to shout about it from the rooftops."
The U.S. Interior Department in January ordered a review of the 2012 drilling program enacted by Shell in the Beaufort and Chukchi seas.
The review focused on problems with the Arctic Challenger spill containment vessel and drill ships Noble Discovery and Kulluk. Shell equipment issues last year and the New Years Eve grounding of Kulluk off Alaska raised concerns about the safety of arctic exploration.
Environmental groups like Greenpeace say exploring arctic environments comes with too many inherent risks in light of the 2010 oil spill in the Gulf of Mexico.
The U.S. Department of Justice and Environmental Protection Agency announced Wednesday Shell agreed to pay $2.6 million in civil penalties and spend $115 on pollution control measures to resolve air quality violations at a Texas refinery.
Shell processes approximately 330,000 barrels of oil per day at the facility, making it the 11th largest refinery in the United States.