Are Greenpeace Activists Pirates?

The Guardian and BBC report that Russian authorities boarded the Greenpeace ship, the Arctic Sunrise, and arrested a number of activists.  I am not immediately clear about whether Russia's military was involved -- The Guardian simultaneously reports that it was the Russian "military" and "coastguard" but the BBC reports that it may have been Russia's "internal security service," the FSB.

Russia claims that it is arresting the activists for crimes arising from a previous protest where members of Greenpeace boarded a Russian oil drilling platform to protest the environmental impact of the drilling operation.

This whole affair reminded me of the Ninth Circuit's opinion in Institute of Cetacean Research v. Sea Shepherd Conservation Society (2013 WL 2278588).  I learned about that case from Kenneth Anderson's post here and from Eugene Kontorovich's in-depth commentary on the ruling here.  In this case, the Ninth Circuit determined that Sea Shepherd's actions of "Ramming ships, fouling propellers and hurling fiery and acid-filled projectiles" was piracy under the United Nations Convention on the Law of the Sea (UNCLOS) because these were violent actions carried out for private ends.  The court concluded that the actions were violent even though property was the target of these activities.  The court further held that "private ends" included actions taken with environmental activism goals -- "private" simply required that the goals be nongovernmental.

For those who are interested in legal issues relating to piracy (who isn't!?), check out Kontorovich's articles on the subject here, here, and here.  

With Institute of Cetacean Research in mind, were Greenpeace's actions piracy?

I don't think so, at least not based on the facts I have seen in the stories I've read.  Greenpeace's actions seemed to be nothing more than an attempt to board an oil platform.  While weapons were displayed, these weapons all seemed to be in the hands of Russian authorities aboard the platform.  I have no idea how concepts like trespass work on the high seas, but in the absence of "violence or detention or any act of depredation," Greenpeace's actions do not appear to be piracy, at least not under UNCLOS.