Geography Reference
In-Depth Information
developments can attract birds and insects, thereby adding to the ecological diver-
sity of the area. However, buildings adopting this approach must be free of cracks
and have a high resistance to water penetration, otherwise the plants will enlarge the
gaps and allow moisture to seep in, which will reduce the life of a building. Associ-
ated with this approach is the use of particular plants on or around the green walls
on buildings that are known to attract insects, butterflies and birds, all of which add
to the local biodiversity. In addition the plants that comprise a green wall provide
greater insulation for buildings on which they grow and create a cooling effect in
summer, in addition to acting as an air filter for the area around.
A more general type of three dimensional green practice can be seen in an in-
creasing interest in the Vertical Farms approach promoted by Despommier ( 2010 ),
which he claims will help feed the 2.4 billion increase expected in the world popu-
lation by 2050. These are really farms in high-rise buildings, for animals or for
crops, and are not just green production additions to buildings such as Green Roofs
or Green Walls. He has argued that the technology exists to grow crops in special
high-rise buildings, using hydroponic means which recycle most of the water used
and through the use of natural lighting systems can operate on 24 h growing cycles.
One of his ideas was to create an agricultural tower, a 30 storey building occupy-
ing a typical city block in U.S.A. producing crops year round, using waste energy
and water inputs from the city and providing the food needs for 10,000 people
(Despommier 2008 ). This may be a new, but compact version of Lloyd-Wright's
( 1932 ideas of self-sufficiency in his concept of a new suburban city called Broad-
acre City, although in that case the food independence was for each family, not for
the city, since it was based on a plan to give them land to grow crops. At first sight
the ideas of vertical farms seem futuristic and uneconomic but examples are crop-
ping up in many cities. For example in densely populated Hong Kong, the permis-
sive land uses regulations, very limited land, and a great local demand has led to a
great increase in agricultural products from mainly informal production on roofs,
or balconies of flat extensions on high rise buildings. Yet even fish farms have also
been developed in high rises, such as the Oceanethix project on the fifteenth storey
of one building which sells 2 t of fish each week from eleven big tanks, a market
helped by the fact that Hong Kong has a high per capita annual fish consumption
of 70 kg. Indeed it is estimated that these vertical food sources account for 2 % of
the total food intake in Hong Kong (Shadbolt 2014 ). Other vertical farms exist or
are being promoted in other Asian cities, but a project in a suburb of Scranton in the
U.S.A. that opened in March 2014 claims to be the world's largest, with 4-5 levels
of growing spaces on a 3.25 ha site that expects to be able to accommodate 17 mil-
lion plants. However these vertical farm projects seem more likely to become part
of the urban scene in Asian urban centres that are densely populated places. In most
cities, and under current price regimes, the prices that need to be charged to cover
costs of these expensive projects mean that the crops will be higher in price, at least
initially, which will restrict the spread of this type of project. But vertical farms may
well be an increasingly familiar part of the urban scene in the future.
Search WWH ::




Custom Search