What once were impassable ocean routes are now open thruways. The some 55,000 ships in the world’s cargo carrying fleet have new shipping routes, and it’s all thanks to the melting of arctic ice.

Back in August 2013, the Yongsheng became the first Chinese cargo ship to travel through the Arctic’s formerly frozen northeastern sea route. The trip took 33 days. Had it gone via the Suez Canal, it would have taken 48 days.

The Yongsheng wasn’t the first one to capitalize on the planet’s changing environment, either. In 2010, four ships traveled through the northern sea route. In 2013, there were 71. Last year, there were 53.

While the melting arctic ice does afford new opportunities, experts say that the risks still outweigh the benefits of traveling through the previously inaccessible sea routes.

“There’s about a thousand nautical miles that’s saved by being able to transit that,” said Finley Foster of business consulting firm Alixpartners. “The problems are really more a matter of the practicality. When you go through the arctic, you’re going through the least-chartered ocean space on the globe of the earth.”

While the days of using arctic routes are still early, and haphazard, scientists at the National Academies of Sciences in the U.S. predict that there will be more ice melted, and therefore more routes opened, by mid-century.

This melting ice is not entirely a boon, however. According to Carbon Brief, which reports on the latest developments and media coverage of climate science and energy policy, melting arctic ice can have dire effects on the environment.

First of all, less ice means more heat. Snow-covered ice reflects 85% of sunlight. Without it, the Earth will absorb more heat.

Secondly, the melting ice could disrupt a part of the Atlantic Meridional Overturning Circulation, a major circulation system that carries warm surface toward northward, giving Europe its more mild climate. In other words, it could change the continent’s climate.

Thirdly, it could increase the severity of winter. Professor Charles Greene of Cornell University told Carbon Brief that “Global warming has increased the loss of summer sea ice in the Arctic, which has altered atmospheric conditions in a manner that stacks the deck in favor of more severe winter outbreaks.”

Although the potential impact of melting arctic ice on the environment is rather unnerving, there is at least one benefit of the new sea routes opening up. According to a discussion paper from the Netherlands Bureau for Economic Policy Analysis, ships will burn less fossil fuel to reach their destination.