On Urban Agriculture and Food Demand in Honolulu
Based upon a comment on the recent CityLab article, I ran some numbers speculating the potential for urban agriculture to meet food demand in Honolulu. Here is the result:
According to a recent study (Loke & Leung, 2013) Hawaii consumes 660kg of food/capita annually; of this 84kg (185lbs) is fresh vegetables. Assuming we just address the fresh veggies consumption of Honolulu’s 400,000 residents (though the above numbers were calc’d with tourists factored in) we’d need to produce 74 millions lbs of veggies (185lbs food x 400,000 people=74,000,000).
Based on GIS analysis I’ve done there are just over 10,000 acres of arable land in the primary urban center of Honolulu (arable being plots: >500sq. ft, less than 30% slope, not paved, water, nor under tree canopy or a building). That 10,000 includes cemeteries, ball parks, and other places of competing use.
If we work backward from 74 million lbs needed and guesstimate 0.6lbs/sq. ft. of production (via Kremer & Deliberty, 2011) there are 2831 acres of land required to meet demand. Of the 10,000 arable acres 3766 are zoned residential (i.e., not an existing farm or soccer field) and so it would take 75% of the arable residential zoned land to meet current demand for fresh vegetables in the city of Honolulu.
Ran this as a quick and dirty calculation so feel free to attack the numbers. But in short it is at least possible spatially for us to meet food demand, feasibility is a whole other beast.
NOTES & CAVEATS:
1. The 3766 acres includes all types of the residential zoning (e.g., Residential Districts 3.5, 5,10, and 20).
2. The population of 400,000 includes the estimated 50,000 residents of East Honolulu despite the GIS analysis only addressing the Primary Urban Center. This means that the likely significant amount of arable residential land from Waialae Country Club to Hawaii Kai is not included in the spatial data. That is to say, there are a number of lawns between Kahala and Koko Head that aren’t factored into the land availability estimates.