A Novel Geoengineering Strategy to Combat Sea Level Rise (2)

In the first part of this post, I described a revolutionary concept to offset global sea level rise by constructing a series of large deepwater lakes in arid environments such as Australia and the Sahara. In this second part, I’ll discuss further scaling up of the concept and some of the many engineering challenges involved.

The final figure in the previous post depicted the first of what Russ Walsh, the guiding force behind this strategy, calls “basic lakes,” 56 by 56 km (35 by 35 miles) in surface area and with depths up to 760 meters (2,500 feet). The next phase of the project would be more of the same – two more basic lakes, as shown in the figure below.

copyright © russ walsh

To hold even more seawater, Walsh envisions building even larger lakes further inland from the basic lakes: a “mega-lake” with a surface area of 100 by 225 km (60 by 140 miles), and a “super-lake” with a surface area of 160 by 240 km (100 by 150 miles). The depths of these massive lakes would range up to a staggering 1.6 to 8 km (1 to 5 miles). For comparison, a super-lake would be about two thirds the surface area of Lake Huron, the 2nd largest U.S. Great Lake, but considerably deeper. The average depth of the world’s oceans is about 3.7 km (2.3 miles).

Clearly, all this construction could not be done at once. The initial goal is to complete the first pilot lake by 2040, the first basic lake by 2050 and the massive mega-lake and super-lake by 2060-80.    

Among the many engineering questions that arise, the most important probably involve the sheer magnitude of the project. As Walsh himself admits, the total amount of earth to be moved will be unprecedented and could fill the Grand Canyon many times over. Past excavation of the Suez and Panama canals pales in comparison. Specialized large-scale digging equipment, from bulldozers to dump trucks and bigger than anything used in mining operations today, may need to be designed and built.

Digging such deep lakes will come with its own problems too, such as possible leaking of groundwater from aquifers or springs, or even flash floods, into the dig site before seawater is allowed to enter. Innovations in pumping and other measures could be necessary. A potential hazard is landslides, although these are more likely to be a problem in surrounding manmade hills than the carefully chosen slopes of the lakes themselves.

Another significant issue is exactly where to locate such a venture. As I’ve mentioned, the ideal location is a long stretch of flat, arid and mostly uninhabited coastal land – something not so easily found in practice. For example, much of the Sahara Desert, while sparsely populated, is unsuitable because it’s at too high an elevation.

A better prospect is Australia. With a vast landmass and a relatively small population, especially in the drier regions that characterize most of the continent, Australia has a geographical climate conducive to year-round construction. It also has a political climate that encourages the shipping of water to inland areas for both people and farming.

The next figure demonstrates just how thinly populated a large percentage of the country is (red and orange areas). And although it’s not evident from the figure, much of the coastline embracing the emptiness is at low elevations highly suited to the out-of-the-box thinking that Walsh espouses. He is currently in the process of identifying other, probably smaller tracts of land worldwide suitable for this gigantic undertaking.

Returning to the issue of repopulation, Walsh expects even the early phases of the project involving construction of pilot lakes to draw people to the region. Initially these would be construction workers, but later arrivals would include millions of others enticed by the prospect of living in a resort-like metropolitan area, replete with rail systems and other infrastructure, and hundreds of miles of walking, biking, and hiking trails. The larger, inland basic, mega- and super-lakes would likely be developed by the pilot lake areas’ new inhabitants.

Seawater lakes in the new settlements could conceivably support ocean habitats, and could serve as carbon sinks via mangroves along the lakeshore, coral reefs near the shoreline and floating kelp farms. New residents living on surrounding hills created by lake excavation could view sea creatures frolicking or watch sailboat races from their balconies and terraces.

While many such possibilities may seem fantasy, Walsh is realistic enough to have estimated the potential costs of the first stages of his venture, which are likely to range up to tens of billions of U.S. dollars. Nevertheless, he sees the project as ultimately yielding a positive ROI (return on investment) for investors, provided funding comes from private corporations rather than government sources.

Further details of both the project itself and its financing are contained in a soon-to-be-published book titled “The SeaNet Vision.”

Next: Challenges to the CO2 Global Warming Hypothesis: (12) CO2 from Antimicrobials Far Exceeds CO2 from Fossil Fuels