A federal judge in Alaska ruled this morning that environmental group Greenpeace USA will be fined $2,500 for each hour its activists block an icebreaking ship from leaving Portland by dangling from the St. Johns Bridge.

U.S. District Judge Sharon L. Gleason ruled in favor of a motion filed by Shell Offshore Inc. on Wednesday in a federal court in Anchorage, demanding Greenpeace comply with a court injunction to cease blocking the icebreaker, named Fennica.

"The daily rate paid by Shell for the Fennica is $59,288," the motion says. "Therefore, Shell respectfully requests that the Court impose a compliance fine of $2,500 per hour until Greenpeace USA has removed its activists from the St. John's Bride [sic] and discontinued any other actions intended to interfere with the Fennica."

That motion was the latest salvo in a federal court battle that began in April, when Shell asked Gleason for legal protection from an "ongoing imminent threat of continuing and additional interference with and irreparable harm to, Shell's 2015 Arctic exploration drilling program and support vessels."

In a hearing this morning, first reported by the Associated Press, Gleason ruled that Greenpeace is in contempt of court, and said the fines begin today. 

UPDATE, 12:41 pm: Gleason's contempt order, just released, says Greenpeace's fines will start at $2,500 an hour and increase.

Starting Friday at 10 am, the fines jump to $5,000 an hour. At 10 am Saturday, they spike to $7,500 an hour; at 10 am Sunday, $10,000 an hour.

The order says Greenpeace will have to give that money to Shell.

UPDATE, 2:13 pm: Greenpeace USA Executive Director Annie Leonard says its 26 protesters will remain on the bridge, for now.

"We are confronted with a huge decision, one we cannot make alone," Leonard says. "Right now we're asking the activists what they think we should do next. While we respect the courts, we also respect the increasingly urgent science that tells us Arctic oil needs to stay underground."