Dispatches from the Northwest Passage

As Arctic sea ice is on the decline, new, previously impassible gateways are opening up for ship transit. One such path is the Northwest Passage – the route between the Atlantic and Pacific oceans via the shallow marine channels of the Canadian Arctic Archipelago. The Arctic is a sensitive barometer for the consequences of global climate warming observed over the past few decades. Such shifts in the natural environment are numerous, but perhaps the most visible change is the drastic reduction in Arctic sea ice extent and thickness that has been directly observed by satellites since the 1970s. It is this decline that is allowing more ship traffic in places like the Northwest Passage – including the Crystal Serenity, the first full size cruise ship to sail the passage. We met her in late August off Ulukhaktok in Amundsen Gulf, the southwest gateway to the Northwest Passage.

I am part of the geological team together with scientists from the Geological Survey of Canada – Atlantic and other institutions that are mapping and sampling the seabed of the Canadian Arctic. There are many more teams on the ship on this part of the expedition, ranging from ecologists to chemists, oceanographers, and atmospheric scientists. From the geology standpoint, we are particularly interested in deciphering how the Canadian Arctic Archipelago evolved since the demise of the great ice sheets that blanketed the entire region some 20,000 years ago. There are many parallels between past and present environmental changes. For example, the behaviour of past ice sheets in the Canadian Arctic can help elucidate how the great ice sheets of today – in Greenland and Antarctica – may respond to future climate change. Similarly, forecasted changes in ocean circulation and their effect on ecosystems can be tested by using the new geological data we have collected these past two (hectic!) weeks.

Reconstructed extent of the last ice sheets in Arctic Canada. White is coverage by ice; thick grey lines denote the position of former ice divides (summits); black arrows mark past ice streams (fast flowing sectors of the ice sheet) that drained the interior of the ice sheets. [Figure from Lakeman et al. (in prep.)]