Experts in the field of Urban Agriculture (or UA) claim that farming in the city could help combat problems associated with global warming.
More than 50% of the world’s population lives in urban areas and the rate of population growth continues to increase. On top of that, urban migration has become a rapidly growing phenomenon. This means cities will have to continue to grow in size in order to cater the unstoppable flow of new immigrants, causing the amount of available farmland to further shrink. This may also leave fewer people to cultivate available land outside of there urban areas, producing less crops. Because of these problematic prospects, many fear that stocking our supermarkt shelves may become a more difficult task in the future, as cities heavily rely on imported foods to support the population.
Problems of heat are probably most often discussed when takling about global warming, the key issues being an increase in global temperature and higher frequency of heat waves. What is essential to this issue, is the fact that cities will likely suffer the most, known as the Urban Heat Island Effect:
- The vast amount of concrete material in cities easily absorb the sun’s heat, which is re-radiated into the atmosphere at night.
- Dark concrete material, like highways, has a lower albedo (the amount of light reflected), retaining more heat.
Decreased evapotranspiration: Concrete structures limit vegetation cover, so the conveyance of water vapour into the atmosphere is inhibited.
Experts have suggested that rooftop farming may offer a solution to these problems, as it serves as natural insulation, and cools and humidifies the air around the building through evapotranspiration. In this way, we would need to spend less energy on things like air conditioning, which produces excess heat itself.
Water Shortage & Floods
Other expected problems are issues of water shortage and floods. In short, the City’s water supply will be put to the test. Again, the concrete surface of cities is the main cause of concern, as much rainfall cannot be absorbed into the soil, which creates run-off water, which:
- Inreases risks of water pollution, threatening our water supplies.
- Increases risks of flooding, which may lead to saltwater intrusion, contaminating our drinking water.
Urban Agriculture is envisioned to help manage these problems, as vegetation slows down water run-off, easing the burden on city drains. Some argue that we could even use wastewater that would otherwise flood the city for growing crops.
- Increasing % of green in cities improves air + water quality.
- Lowering temperatures + moderating intensity heat waves will lead to less fatalities (e.g. dehydration).
- Reduced flooding minimises health effects of exposed sewage material caused by overstressed urban water systems.
- Vertical farming less affected by health risks flooding than traditional ground level farmland.
- Using wastewater to grow crops improves sanitation by relieving water systems + by reconditioning soil.
- Increased amount and quality urban soil + range of crops supports richer biodiversity.
- Localised food supply reduces packaging and gas emissions + makes for fresher food.
- UA methods are cost-efficient, cutting food expenses, leaving more income to spend on healthcare.
What are your thoughts about these ideas? Do they seem realistic enough?