Have you been hearing news recently about the “Doomsday” glacier and an impending sea level rise disaster? If so, then perhaps the following Corner will ease your concern – a bit. What and where is this “doomsday” glacier. Its official name is Thwaites Glacier in Antarctica, a mass of ice the size of Florida. The reason for concern is that it is currently losing about 50 billion tons of ice each year and contributing approximately 4% to the annual global sea level rise of about 1/8 inch per year. The rate has doubled since 1993 as measured by satellite altimeter records. This glacier alone contains sufficient ice to raise sea levels by two feet and it is a keystone that holds back other ice sheets from flowing into the ocean. Thwaites total collapse cold unlock a total of more than 12 feet of global sea level rise. So what is the true story?
Let’s begin by recognizing that it is complicated. Thwaites is grounded but warming Antarctic Ocean water is increasing the melt rate as it moves under the glacier. A diagram will help explain the story. Thwaites contains a lot of ice! It’s maximum depth is nearly 4,000 feet thick. When you look at the illustration, you will see a “grounding line” which prevents the rapid movement of the glacier. Ice flow moves over the grounding line and the floating ice sheet now extends approximately 75 miles into the Amundsen Sea. Under the floating ice sheet ocean currents bring warmer water and, as yet, not fully understood currents. The nature and understanding of this current system is critical to understanding the basal melt rate of the glacier. The September 27th Science article states that “the ice fills an immense lowland that sits below sea level and deepens inland. That topography raised fears that, once Thwaites pulls back from a bedrock ridge, or sill, that helped to slow it down, warm ocean waters will rush in, eating away at the glaciers underbelly and accelerating its retreat.”
Currently, huge masses of glacial ice continue to break off at the ice/ocean interface forming large icebergs and feeding the increase in sea levels. Keep in mind that the whole system is dynamic as there are large tidal fluxes that raise and lower the glacier at it’s ocean interface.
So where does this leave us today. Should we take the dire warnings seriously? According to the 27 September 2024 Science article which is based on the work of a 100-person team – the International Thwaites Glacier Collaboration (ITGC) working since 2018, “the glacier has stabilized somewhat – in the short term.” This group projects that Thwaites will likely contribute approximately 2.4 inches to sea level rise by the end of this century – with a total sea level rise by the year 2100 of 15 to 30 inches. That estimate is conservative and assumes no major increase in the rate of climate change. There are many other factors that could kick the melt rate into a much higher gear including the increasing rate of methane release from the rapidly melting permafrost in the arctic. Methane is a more powerful greenhouse gas than carbon dioxide! The science article states that “the longer-term outlook is indeed grim. Under a worse-case scenario for emissions, Thwaites and many of the ice sheets it buttresses could collapse by 2300, adding more than 4 meters to sea level.” It is also not comforting to be entering a period of politics in the United States where key political voices are not listening and either ignore or deny that humans are impacting the global climate. Keep tuned and keep praying!
Our prayer: Lord, we ask you to provide guidance to those working to understand the dynamics of your wonderful and mysterious Creation – as we seek to be responsible stewards of this amazing world. We also pray that you will open the eyes and ears of those in powerful positions that they may respond with your love and care of this sacred place we call Earth. Amen.
Thanks for listening.
— Joe Sheldon
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