Question:
regarding Thwaites: I note that tectonic sources create warm water currents that are increasing the melt rate of the shelf and glacier, moving the grounding line inland. It seems that this is a “natural” occurrence, not related to climate change. If we are using Thwaites as an example of climate change, how do we separate out the “natural” tectonic warming from that created by warming oceans and atmosphere? Seems that Thwaites’ threat to sea level would occur even without climate change above. Appreciate your thoughts!
Hello Edward,
At present, the most significant influence on ice shelf melt in the Thwaites Glacier is ocean heating driven by climate change. Oceans temperatures are rising due to the increasing air temperatures from human activity, and because oceans retain heat for longer than air, they are getting warmer and warmer. Increasing atmospheric temperatures are having a knock on effect on polar wind, which subsequently causes changes to ocean circulation. The most notable change in Antarctic ocean circulation is the increasing frequency of warm circumpolar deep water intrusions across the continental shelf at the Thwaites Glacier, bringing warmer water up to the grounding line. Therefore, the presence of this warmer water is a result of climate change impacting on ocean circulation, and is not related to plate tectonics.
I hope this is helpful,
Holly