In the past decade, there has been a push to create giant new Marine Protected Areas (MPAs). They now cover nearly 9.7 million square miles, equivalent to more than the land area of North America. Cristiana Pașca Palmer, executive secretary of the UN Convention on Biological Diversity, says the world is on course reach the convention’s target of having a tenth of the oceans protected by next year.

But questions are being raised. The growth has been driven by the formation of giant MPAs bigger than many countries, often in remote regions where the threat to biodiversity is lower. So, critics are asking, are countries creating big distant MPAs to distract attention from the harder task of protecting trashed coastal ecosystems closer to home? And is there a geopolitical game afoot, a stealth rush to control the oceans for political ends? And does that explain why half of the ocean waters covered by MPAs are in the hands of the United States and two former European colonial powers, Britain and France?

Most ocean scientists see the rush to create vast MPAs as a boon to marine conservation. They are cost-effective, connect different marine ecosystems, and encompass larger parts of the ranges of migrating species such as whales and tuna, protecting “corridors of connectivity among habitats in ways not afforded by smaller MPAs,” says Bethan O’Leary, a marine scientist at the University of York in England.