A lot of people are economical with the truth when they talk about the consequences of drilling for oil.

The industrial lobby all but ignores the possible downside for natural habitats; the environmental lobby is liable to imply that every project could precipitate a crisis. The truth, inevitably, is somewhere in between.

The first and most important thing to note when assessing the wisdom of this particular decision is the difference between exploration and exploitation. It's simple enough: exploration is the process of checking if a site is worth drilling; exploitation is the extraction of the oil. But the distinction is crucial.

The environmental risks of the exploration stage are minimal: the work is on a much smaller scale than it would be if the sites were to prove useful, and hence much less likely to lead to any kind of spill. These are the kinds of wells that Shell is proposing to drill, at least initially. So it is perhaps a little early to talk of a crisis for the habitat.

Meanwhile, the prospects of exploitation proceeding cleanly and straightforwardly are improving as the relevant technology does. It is possible that these risks will have receded further by the time Shell comes to the exploitation stage.

In the end, though, exploitation is the aim. What will be the risks if that does come about? Well, there are big problems with carrying out a cleanup in the region. The extreme low temperatures, strong winds, high seas and vast seasonal variations off the coast of Alaska would make it very difficult. While some of the region's species have a tremendous capacity to recover, the cleanup process would be very slow. With very little experimentation done on the subject, it might be argued that you should err on the side of caution.

And yet, at the same time, the mythology of the area is sometimes overblown. The protected Arctic Refuge, for instance, is set aside as a kind of idealised natural habitat. But already there is human activity there: the indigenous people, hunters and trappers, whalers and sealers, traders and even military personnel. The word pristine should be used with great caution. As extraordinary as the region is, it is far from untouched by humanity.

The author is a senior associate of Cambridge University's Scott Polar Research Institute