Actually, I've had the pleasure of working with an international lawyer on that question related to Arctic shipping in Canada. There is a long list of issues to consider.
Of course, the greatest concern is oil spills. Given the danger of uncharted territory in many parts of the Arctic.... We have very poor charts and bathymetric charts in many areas. The ice is changing very rapidly. It's a lot less predictable than it was in the past. We need to understand more about what happens if there is an oil spill. How quickly will that degrade and break down?
There's research going on, including with local Inuit communities, to try to understand response and recovery times of the ecosystem to oil spills. The results to date indicate that there will be a very persistent effect of any spill of that sort.
However, there are other questions that relate to, for example, underwater noise in shipping. The Arctic Ocean is a very quiet place because of that ice cap—