Dan Barber's advocacy of Veta la Palma's production process will not scale.

Veta la Palma produces 1,200 tons of sea bass, bream, red mullet and shrimp each year. Low density — roughly 9 lb. (4 kg) of fish to every 35 cu. ft. (1 cu m) of water. The farm exists on 27,000 acres. 0.04 metric tonnes of fish per acre per year.

Human consumption of fish annually is 110.4 million metric tons. Seafood provides more than 2.9 billion people with at least 15 percent of their average per capita animal protein intake. You would need 4.3 million square miles of managed wetlands to meet current global demand for fish using Veta La Palma system. You'll need even more if consumption increases with population projection of 10 billion people. Wetlands are going to be particularly hard hit by climate change. Global wetlands: 11.8 million square miles. Global land: 57.2 million square miles.

Veta La Palma fish farming as a commodity will be a luxury at best.

In 2006, 51.7 million metric tons of seafood was produced by fish farming. So we are already meeting a substantial part of demand through aquaculture. Mostly intensive aquaculture.

I'm more a fan of intensive indoor recirculating aquaculture. Blue Ridge Aquaculture: 10,000 pounds of tilapia per day in its 80,000-square-foot facility. That's greater than any other operation in the United States. It has only 35 employees. 1614.788 mt per year on 1.83 acres. 883 mt per acre per year. It does have much higher energy inputs than the Veta la Palma system. However, it seems much more ecologically friendly than outdoor intensive fish farms.

this is true, the whole Veta la Palma site is 27,000 acres, but the part that is dedicated to fish is only 8,000 acres which gives a output per acre of .15 metric tonnes of fish (not the .04 you calculated) per acre per year in the end only 1.15 million acres of wet land are needed to make fish for every one in the world which is only a tenth of the worlds wetlands. but in the end fish is food and we must think do we want healthy natural fish or factory bred fish. btw what is wrong with devoting less then 2% of our global land to raising organic fish. did you see Blue Ridge Aquaculture's youtube video it was fish being fed soywheat pellets and swarming in their own waste. fish raised in those conditions taste horrible, besides that he need thousands of acres of wheat grown just for his fish. Blue Ridge Aquaculture system is not sustainable.

Bill Dunster's remarks on integrating housing with flood protection in the Thames gateway, and using the sale of that housing to fund the construction of the flood protection, was thought-provoking. In Seattle, we are discussing a replacement for our downtown seawall, and it's been suggested that we need to consider the possibility of sea-level rise when designing the replacement.

Considering the sort of solution proposed for the Thames Gateway in Seattle raises some interesting possibilities. Sale of the right to build properties on the wall itself could help fund its construction and increase the concentration of activity downtown by boosting density. We could have benefits like reduced public cost and greater density along with increased protection from seismic events and the effects of climate change.