An interesting piece by Adele Peters of FastCompany describes shoes made partly from a funky kind of plastic derived from algae.
The Ultra III shoes, made by a company called Vivobarefoot, are partly made with algae skimmed from freshwater lakes. This algae is turned into a foam that is blended with a standard plastic, ethylene-vinyl acetate, to form the material for the shoes.
The Chinese government is apparently interested in applying this process to clean up an algae bloom on Lake Taihu and probably elsewhere.
There is an obvious way in which such an effort, if successful, is an environmental win. Algae blooms can be quite damaging to aquatic ecosystems. They are often prompted by runoff of agricultural fertilizer, and have become a perennial problem in Lake Erie, for example. So, any process that reduces the amount of algae in a lake should reduce the pressure on the lake's ecosystem that would otherwise result.
However, there is a potential downside. Turning pollution into profit could create a vested (and perverse) interest in maintaining the flow of pollution. If the supply of sustainable footwear depends on copious agricultural runoff into lakes and streams, then there would be so much the less incentive to reduce the flow of agricultural pollutants in the first place.
Consider the Steamboat Act of 1852. Among other things, this Act required safety vents and thicker hulls on the boilers of Mississippi steamboats. The Act was passed after a rash of fatal boiler explosions: Boat captains were in the habit of running their engines hot in order to make maximum speed. Time is money!
The Act did not decrease the level of risk. One reason was because captains ran their boats even harder: After all, the increased safety afforded by thicker boiler hulls meant that boilers could be run hotter still—up to a point. In short, increased safety margins were undermined because they could be converted into increased profits.
Perhaps the same could happen in the case of algae blooms. If a company that harvests algae for plastic can reduce the risk of blooms, producers of pollutants may be able to convert that increased safety margin into profit by relaxing standards of runoff prevention.
In terms of sustainable design, turning a pollutant into a product seems like an easy win for the environment. However, it does not close the loop by actually inhibiting the pollution itself. In the worst case, it could even entrench or exacerbate the source of pollution.
It is not clear that making some shoes from algae will lead to environmental disaster. The outcome depends on many factors particular to the situation at hand. However, it is also not clear that it will lead to an environmental benefit either.