One million square miles of the Arctic Ocean will be protected for at least the next 16 years after major nations, including Canada, China, Russia and U.S. signed a moratorium on fishing the arctic while research is conducted in the once-frozen stretch of ocean.

Rising global temperatures have opened new avenues for commercial fishing and freight traffic, but increased commerce is expected to negatively impact the arctic’s marine ecosystem coupled with climate change brought on by global warming. Currently no commercial fisheries exist in Arctic waters.

The move is being hailed by conservationists as a key deal, albeit temporary, with Greenpeace and other conservation groups supportive of the effort as the far north warms at nearly twice the global average rate. Global warming is impacting the size and distribution of fish stocks that may become more attractive to fisheries in the future.

Canada, China, Denmark, the European Union, Iceland, Japan, South Korea and the U.S. signed the agreement that covers an area roughly the size of the Mediterranean Sea and states “that no commercial fishing will take place in the high seas portion of the central Arctic Ocean while we gain a better understanding of the area’s ecosystems.”

David Balton, U.S. Ambassador for oceans and fisheries, hailed the agreement in a statement following the announcement. Balton will leave the state department for the Wilson Center’s Polar Initiative as a fellow next year, diminishing the country’s role in Arctic work. His anticipated departure is the latest in a string of state officials to leave office over disagreements U.S. President Donald Trump’s limited views on climate change and the hollowing out of the U.S. State Department.

“This is one of the rare times when a group of governments actually solved a problem before it happened,” Balton said. “In the future if fish stocks are plentiful enough to support a commercial fishery there, they will be part of the management system and presumably their vessels will have the opportunity to fish for those stocks.”

All signing nations agree to establish “appropriate conservation and management measures” going forward, according to the agreement.

Karmenu Vella, EU Commissioner for the Environment, Fisheries and Maritime Affairs called the agreement “historic.”

“It will fill an important gap in the international ocean governance framework and will safeguard fragile marine ecosystems for future generations,” Vella said.

Canada-based group Oceans North said the agreement would add further protections to vulnerable marine arctic species, according to representative Trevor Taylor.