January 24, 2013
Local and Global Insights on Sea Level Rise
The low levels of Lakes Michigan and Huron have received ample press recently (CNN, National Geographic, FOX, Canada Free Press) as the economic costs of low water levels become more apparent. At the same time, Hurricane Sandy’s aftermath continues to spark debate about how to boost the resilience of coastal cities in an era of rising sea levels and extreme weather events. While I am inspired by the attention that these two environmental shifts are receiving, clear explanations of their causes are hard to find. The role of global climate change in these events can be especially difficult to discern.
A panel last week at the Shedd Aquarium — Social and Biological Impacts of Rising Seas and Reduced Lake Levels – addressed the complexities of sea and lake level projections. Two ecologists, Ben Strauss of Climate Central and Phil Willink of Shedd Aquarium, presented alongside Anthony Oliver-Smith, Professor of Anthropology at the University of Florida. The projections they shared were not exactly uplifting, but their insight was refreshing nevertheless.
Scientists are currently projecting 2-5 ft (0.6-1.5 m) sea level rise by the end of the century, based on several factors:
- Thermal expansion – As water temperatures rise due to climate change, the water itself expands under increased temperatures. This expansion spread out over the oceans is expected to increase sea levels 1ft per century.
- Retreat of land-based glaciers – If all the world’s mountain glaciers melted, there would be a 2-3 ft increase in sea level.
- Ice sheet loss – Greenland and Antarctica are melting faster than previous predictions. From 2004-2007 loss of Greenland’s ice sheet is the area of 14 states, 3 ft thick.
- Land subsidence and uplift – Some land area are sinking and others are rising. Land can sinks due to groundwater depletion (e.g., Tianjin, China), and the Great Lakes area is recovering from glacier pressure.
SOM’s City Designers who attended found several points and questions especially relevant to the future of the Great Lakes:
- We must integrate the concept of change into civic planning and management. Natural systems are dynamic, yet people and infrastructure to not adapt well to fluctuations in their environment. How can we design our cities to be more flexible in the face of ever evolving conditions?
- Declining lake levels in the Great Lakes Basin reflect a 70 percent decline in ice cover over the last decade, which has led to increased evaporation. Lake Michigan is at an all time low of 6 ft below average. Falling lake levels may drop significantly below the level of the Chicago River, which would require the Army Corps of Engineers to either lower the water level of the Chicago River or re-reverse the flow of the river.
- We must consider both exposure (geographic, physical) and vulnerability (social construct: poverty, access to resources, coping mechanisms) when considering people’s risk for sea level rise. Developing coastal cities in Asia are some of the most exposed locations and the people moving there some of the most vulnerable. Considering this distinction, we must focus on reducing exposure and vulnerability.
- Displacement and resettlement due to sea level rise can be considered a secondary disaster if not done properly. People tend to think of resettlement/relocation as a physical process, but we shouldn’t ignore the social impacts of losing relationships and adapting to new places. Social networks are especially crucial for poor people who rely on them for key resources.
- There are some big unknowns about how sea level rise will cause settlement patterns to change:
- Will migration be internal or international?
- Will people move because of severe events or will there be a gradual shift away from coasts?
- Will individuals or whole communities move?
- Furthermore, what are the outcomes of mass migration due to climate change? What areas can take the influx? What will the living conditions be? What happens to the abandoned places?
Thanks to Shedd Aquarium and the University of Chicago for hosting this relevant and informative event.