Arctic's Hudson Bay at tipping point

Since the mid 1990s, Hudson Bay is one of the Arctic’s last refugia (an area in which organisms can survive despite periods of harsh weather conditions) having undergone dramatic climate-driven changes and has reached an ecological tipping point. This is worrying, as until recently, the icy lowlands around Hudson Bay have remained resistant to global warming. This is due to the antecedent high temperatures in the Arctic.

A Paleolimnologist at Queen’s University stated that there were always a few refugia that seemed relatively resistant to change including the area around Hudson Bay. This is because Hudson Bay is the second largest inland sea in the world, and it is blocked with ice that helped keep the area cool. Inevitably, Hudson Bay was going to pass a tipping point. Recently, due to the increase in temperatures, the ice has started to melt. Since the 1990s, Hudson Bay has warmed about 3^oC.

Sediment cores and the ancient algae they contain show that the Hudson Bay region’s lakes experienced very little change over the centuries. This has now changed after the mid-1990s, the aquatic biota in the sediment record show striking shifts in ecosystems that are very similar to those seen elsewhere across the Arctic in regions where air temperatures warmed and time periods of ice-free water increased.

Physical changes around Hudson Bay could resemble those seen earlier in the high Arctic including less lake ice, shallower lakes and dried up ponds, along with the loss of productive wet peat lands. This climate change has had a large negative impact.