#9 Climate Considerations
Resource Centres on Urban Agriculture and Food Security (RUAF) states that globally, cities produce about 70 percent of greenhouse gas emissions. The urban population worldwide is expected to double by 2030 with much of this urban growth taking place in developing countries. Accordingly, about 90 percent of the expected increase in greenhouse gas emissions will be from the rapidly growing cities in developing countries (World Bank, 2010). The World Bank also states that cities not only are main contributors to climate change and suffer most of its impacts but also hold important competencies to act on climate change (e.g. authority over land-use zoning, regulation of energy supply and industrial emissions, waste management and water services).
New York State’s climate is very diverse. It is not uncommon that just ten miles away, you could move from one microclimate to a completely different one. Urban climates, in particular, are warmer than their rural surroundings and often full of microclimates. The University of Georgia College of Agricultural & Environmental Sciences provides an overview of microclimates at http://ugaurbanag.com/content/microclimate.
According to the EPA, annual mean air temperature of a city with 1 million people or more can be 1.8–5.4°F warmer than its surroundings, and the difference can be as high as 22°F in the evenings (http://www.epa.gov/hiri/). As such, the climate of an urban farm may be very different from that identified on the USDA Hardiness Zone Map ((http://planthardiness.ars.usda.gov/). Urban farmers should consult with other growers in their area to learn more about their neighborhood’s growing conditions.
For more information about the climate in a particular area of NYS, check the Northeast Regional Climate Center website: www.nrcc.cornell.edu/index.html or call 607-255-1751.
Climatic Factors that Impact Crop Growth
Climatic factors that impact crop growth include minimum temperatures, hardiness, frost-free dates, growing degree-days, precipitation, air drainage, and wind exposure. You can learn more about these factors on the Northeast Beginning Farmer website at https://smallfarms.cornell.edu/plan-your-farm/accessing-evaluating-land/evaluating-land-tutorial/.
Additionally, extreme weather events—the increased frequency and severity of rain events, hail, tornadoes, drought, hurricanes, extended periods of previously abnormally high or low temperatures—can impact plant health, yield, soil erosion and more. The following provide general information on extreme weather and its impact on farms:
- The National Wildlife Federation’s “Can Soil Save Us?” argues for cover cropping to reduce the effects of changing climate: http://www.nwf.org/~/media/PDFs/Water/2015/Drought-and-Flood-Report-Final.pdf
- University of Minnesota Extension has a comprehensive resource for coping with many types of extreme weather: http://www.extension.umn.edu/extreme-weather/
- Clean Wisconsin’s “Seeds of Change” report quantifies the impacts of extreme weather on farmers to better illustrate the threat of extreme weather: http://www.cleanwisconsin.org/wp-content/uploads/2014/12/ag-report-extreme-weather-climate-change-clean-wisconsin-web.pdf
Climate-Appropriate Urban Farm Planning
For more information on climate-appropriate urban farm planning, see:
- The Cornell University Garden Ecology Project’s “Garden Planning Handout,” with approximate best planting dates for vegetables and cover crops in the New York City area, available at https://smallfarms.cornell.edu/gep/files/2012/09/Garden-Planning-Handout-1bb9z1l.pdf; and
- Bronx Green-Up’s “NYC Gardener’s Calendar,” which includes information on planting, published in the GreenThumb Gardener’s Handbook (p. 29) and available for download at www.greenthumbnyc.org/pdf/gardeners_handbook.pdf
Growing Methods for Climate Adaptation
Urban farms can help mitigate changing climate conditions and also prepare for resiliency to these conditions through a variety of farming approaches that sequester carbon, reduce storm water runoff and make use of “waste.”
For additional information on these approaches, refer to Factsheets:
11 – Raised Beds
13 – Root Top Farming
14 – Intensive Techniques
15 – Hydroponics
23 – Composting
28 – Rainwater Harvesting
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