Rooftop farming

URBAN ROOFTOP FARMING AS A CLIMATE SOLUTION Jess Wallach EDUC 536: Urban Ecology December 15, 2015

Deep Dive and Education Synthesis

Global challenges; local opportunities As climate change causes global temperatures to rise and rainfall patterns to shift, agricultural yields are expected to decline in most countries (Oxfam 2014). More frequent and more intense extreme weather events such as floods, droughts, and heatwaves also threaten food production (FAO 2007). Extreme weather events are also likely to damage transportation infrastructure, interrupting food supply chains and increasing food price volatility (Oxfam 2014).

While these are global concerns, urban food systems are particularly at risk. Many cities depend on concentrated distribution channels and aging infrastructure that are highly vulnerable to climate-related disruption (Dubbeling 2014). Moreover, the integration of conventional food systems with other vulnerable urban systems like electricity, water and public transportation creates significant risk. In the event of a blackout, for example, food distribution and storage systems that depend on refrigeration will be useless. If public transportation fails, as it did in New York City during Hurricane Sandy, urban residents may be unable to access grocery stores, food banks, and other important food sources (Cohen 2014). This is of particular concern for low-income communities, who already spend a higher portion of their income on food and have less access to food centers (Morello-Frosch 2009). For many low-income families, this means making a choice between having nutritious food and having enough food, a choice that will only be exacerbated by climate change (Kang 2013).

Yet this crisis is also an opportunity. Preparing for the impacts of climate change in the future means transforming urban environments now - creating healthier, more vibrant, and more just cities for all.

Urban rooftop agriculture as a climate solution The complex nature of cities means that there is no ‘silver bullet’ for enhancing urban food security in a changing climate. Rather, planners, policymakers and communities should look to a suite of solutions that address vulnerability while also tackling the root causes of climate change.

Urban rooftop agriculture is one such solution. In the following briefings I explore how scaling up urban agriculture can contribute to a more productive and sustainable urban food system. Each briefing highlights a different approach to rooftop farming, with an emphasis on growing strategies, new technologies, and successful community/consumer engagement. While these briefings were created with policymakers in mind, they may be relevant learning material for anyone interested in transforming unused urban spaces into vibrant green places.

Recent innovation in rooftop growing systems and practices such as hydroponic growing systems, light-weight soil systems, “smart” technology greenhouses and aquaponics have made urban rooftop agriculture more efficient and less resource-dependent than conventional agriculture. Some of these technologies, such as light-weight soil systems, allow urban farmers to grow food on rooftops that could not otherwise support the weight of a traditional soil system. Others, such as small-scale hydroponics, allow urban farmers to move crops indoors when extreme weather hits. Many of these innovations reduce water use, some as much as 90% compared to conventional agriculture. In a climate-challenged world where droughts are more frequent and fresh water is an increasingly precious resource, these approaches are promising and very much needed.

All this adds up more food and more reliable food in urban spaces – by some accounts, a lot more. The Gotham Greens farm, featured in this report, boasts that it’s half acre rooftop produces as much as a 10 acre soil-based farm. Researchers studying a rooftop aquaponics farm in Basel, Switzerland, estimated that if just 5% of the city’s rooftops – 328,000 sq ft, or about 5 ½ American football fields – was converted to aquaponic farming, they could produce 8-20% of the city’s fresh vegetable and fish consumption. Keeping food local and accessible helps buffer against unexpected disruptions in the food supply as well as longer-term price increases.

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Beyond emergency preparedness, urban rooftop agriculture can play a major role in climate mitigation and carbon emissions reduction. Commercial scale food production on city rooftops reduces greenhouse gas emissions by decreasing food miles traveled and energy use. For some context, the average industrially-farmed tomato travels over 1,000 miles to reach its consumer (Pirog and Pelt 2001); the tomatoes at the Laval farm in Montreal travel on average less than 2 miles. Additionally, rooftop farms insulate the buildings beneath them, reducing energy and cost for heating and cooling. As commercial and residential buildings account for 39% of carbon emissions in the U.S, the potential for energy savings –and a corresponding reduction in GHG emissions – is huge (US Green Building Council).

Additional Benefits Perhaps what makes urban rooftop farming most promising as a food security solution is the number and diversity of co-benefits, including but not limited to: 1) Storm water management. Rooftop farms can significantly slow the rate of storm water runoff. The Navy Yard Farm in Brooklyn, for instance, manages over one million gallons of storm water per year, reducing stress on the city’s overtaxed storm water system and decreasing the amount of waste water that flows into NYC’s open waterways.

2) Reduction of the urban heat island effect. Transforming heat-reflecting roofs into absorbent green growing spaces helps to reduce the urban heat island effect (Dubbeling 2014). Reduced building energy use (described above) also decreases the amount of ambient heat contributed by the built environment.

As climate change will make heat waves more frequent and intense, this is an important secondary role for rooftop agriculture.

3) Waste reduction and diversion. Rooftop farms which compost on-site divert organic matter from urban waste streams, reducing waste volume and retaining valuable nutrients. Farms which distribute their own produce, such as the Laval farm, also help reduce waste by using less packaging.

4) Creating local economic opportunity. Partnerships with educational non-profits and social services allow farms like the Brooklyn Navy Yard to provide job training and skills workshops to community members.

Rooftop farms also create green jobs within communities and, like the Laval farm, may support other local producers and makers.

5) Increasing access to green and open spaces. Research shows that access to green spaces has a significant positive impact on human health and well-being (Beatley 2011). Rooftop farms which are open to the community, such as the Brooklyn Navy Yard farm and the Bell Book and Candle farm, contribute to this healthy relationship.

6) Increasing availability of nutritious food. As demonstrated in these briefings, urban rooftop farms have the potential to increase the quality as well as the quantity of food available in urban areas. Compared to conventionally grown food, which often travels thousands of miles and multiple days to reach consumers, food grown on urban rooftops reaches consumers within a few hours or a single day. Because of this, it is fresher and retains more of its nutritional value (Frith 2007). The rooftop farms highlighted in this project also use fewer or no pesticides, relying instead on beneficial insects to manage pests.

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Challenges and Opportunities While these innovative approaches to food production are being adopted in cities around the world, several key challenges remain to scaling up urban rooftop farming.

First, more research on productivity, energy offsets, and local economic impact is needed. In creating these deep dive briefings, for instance, I found that many interesting projects were without accompanying data – which meant that I passed over them in favor of exemplars with more detailed information and results. In real life situations, this research gap means that innovative ideas may be overlooked or diminished.

Integrating established rooftop farms into local food economies is also a major challenge. As noted in Briefing 5, distribution challenges and inaccessible local markets limit the role that rooftop farming currently plays in urban food systems. Several solutions are highlighted in the briefings below; however, these solutions are largely farmbased and do not address the structural challenges associated with market monopoly of large corporate distributors and grocery chains.

The expansion of urban rooftop agriculture can be enhanced or limited by city policies. New York City, for instance, has emerged as a leader in rooftop farming as a result of the city’s grant programs and flexible zoning. In contrast, urban rooftop farming has been slow to take off in Seattle, given the city’s more restrictive zoning codes. Integrating rooftop agriculture into building codes is thus an important first step. Implementing broader policies which mandate, subsidize, or otherwise incentivize developers to build rooftop farms is politically more difficult but also more impactful. Toronto, for instance, has a policy that requires developers of industrial buildings larger than 6,500 sq ft to install green roofs. Adopted in 2009, it has already resulted in more than 643,00 sq ft of new green roof construction in the city (City of Toronto 2015). While these green roofs are not necessarily for food production, a similar policy could be put in place which focuses on rooftop agriculture.

Subsidizing rooftop farm construction is also an opportunity to build equity into the urban food system. As demonstrated in many of the briefings below, building rooftop farms is extremely expensive. This is a major barrier for individuals and communities without access to capital, political resources, and other means of investment. As low-income people will be most impacted by food price swings and increases, creating pathways to urban rooftop farming for and within these communities is essential as well as equitable.

Expanding access to urban farming can also build social cohesion. In the case of extreme weather events, social cohesion is often the first line of defense. In communities with high levels of interaction and participation, community members are more likely to check in on elderly, sick, and young neighbors - those who are most vulnerable and at risk (Ross 14). Overall, cohesive communities are less negatively impacted by extreme weather events (Baussan 2015). Green spaces like rooftop farms serve as "neutral" or positive spaces where people come together and build relationships. Because they encourage a common purpose and collaboration, rooftop farms can contribute to stronger communities and increased social capital (Wolf and Rozance 2013).

As evidenced in the briefings, some rooftop farms are more engaged in the surrounding community than others.

Recognizing that many of these farms are private businesses, developing policies and programs which encourage community connections is essential. Public-private partnerships, as well as grant programs and non-profit collaborations, can support privately owned urban farms in providing volunteer opportunities, skill shares, internships, public events, and farm-to-school relationships. This last opportunity is explored in more detail in the education section below.

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Educational Application: rooftop farms as learning labs Supporting school-to-farm connections is an important strategy for policymakers and advocates looking to build community energy around a policy or program that expands urban rooftop agriculture. As we learned in Kristine Cramer’s (2015) presentation, engaged students can often share information and enthusiasm for local initiatives with their families much more effectively than local government can. Fostering connections between farms and community institutions like schools and other education organizations can also contribute to social cohesion, a key factor in climate resilience.

Beyond this, rooftop farms are unique and potentially transformative learning environments for urban students.

They are opportunities to bring global issues like climate change, water and energy efficiency, and sustainable food systems to a scale where students can see their own role and impact. Making these issues relevant to students’ everyday lives is essential if this knowledge is to be empowering and not overwhelming (Ezekiel et., al, 2015).

The educational applications highlighted below focus on building understanding of complex urban systems and the impacts of climate change through problem-solving approaches. Using rooftop farms as the context for this learning models a solution to the global challenges students are learning about; hands-on and inquiry-based learning empower students to take action . They can be adapted for learners at a variety of levels.

Tackling Climate Change, "One Seed at a Time" This dynamic curriculum from Cornell Garden-Based Learning affirms that learning about climate change doesn't have to be overwhelming or disempowering. With an emphasis on citizen science, this series of lesson plans engages students in learning about and monitoring climate-induced changes in their garden (in this case, an urban rooftop farm). Through this inquiry process youth learn about the causes and consequences of climate change; their local garden is an entry point to broader discussions about the global environment and food security.

The curriculum's emphasis on student-led action ensures that these broader discussions about climate change are catalyzing rather than paralyzing. Students are encouraged to apply their learning by exploring how to adapt growing practices to fit the environmental changes they've observed. They play an active role in climate mitigation by creating "greener" gardens and adopting other sustainable practices. Situating this learning in or in partnership with an urban rooftop farm helps students helps students see the real-life implications of their learning while making a tangible difference in their community.

The "One Seed at a TIme" curriculum draws on a variety of learning methods and modalities. Visit the project website to explore the curriculum and access lesson plans: http://blogs.cornell.edu/garden/getactivities/signature-projects/climate-change-in-the-garden/introduction/

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Exploring Interconnected Urban Systems Rooftop farms offer many benefits to cities beyond local food production. Investigating these co-benefits is an opportunity to build student understanding of interconnected urban ecosystems, as well as identify how their everyday actions shape and are shaped by these systems.

Like the "One Seed at a Time" curriculum, the following projects support hands-on student learning that help students understand how they can be a part of the solution to global challenges.

1) Design a Green Roof (adapted from an eGFI lesson by Mary Lord) In this inquiry-based lesson, students explore how rooftop gardens impact the temperature inside and outside a building. Student teams are tasked with designing two model buildings: one with a 'green roof' and one with a traditional roof. Using heat lamps and thermometers, students will model, measure and graph the ambient and interior temperatures of the model buildings. Students will then analyze this data to determine how rooftop gardens impact building inhabitants and the urban environment.

This activity is an opportunity to introduce concepts like the urban heat island effect, as well as emphasize connections between the built and natural environments.As an extension of the lesson, students can work together to design their own rooftop farms. Applying what they've learned about how different surfaces contribute to the urban heat island effect, students will understand how they can transform buildings to make their community healthier and more sustainable.

Students collecting data on their model buildings.

(Credit: eGFI)

Students can continue this investigation outside of the classroom by visiting rooftop farms and collecting data.

Building on this learning, students can work with adults in their community to identify opportunities for creating green roofs and reducing the urban heat island effect. For older students, this is a fantastic opportunity for taking action - students can work with experts in their community to site potential green roofs, learn about the rooftop farm construction process, build community support and gather resources for the transformation of these unused urban spaces.

For specific instructions and materials list, visit: http://teachers.egfi-k12.org/design-a-green-rooftop-garden/ 14 | U r b a n R o o f t o p F a r m i n g

2) Rooftop farms and storm water management A similar learning opportunity could be designed for investigating the role of rooftop farms in storm water management. In the classroom, students could design and test different rooftop surfaces (such as tar paper, concrete, glass and 'green roofs') to see how rain water moves over these surfaces. Students can measure the rate of runoff, absorption rate, and contamination levels in order to understand how different surfaces impact storm water systems. Complimentary activities could include visiting different urban rooftops during rainstorms to observe how water falls and is distributed.

This inquiry and observation is a useful entry point to discussing storm water systems, as well as how rooftop farms can play an important role in storm water management. Connecting this to climate change, which brings more frequent and intense storms, helps students recognize opportunities for intervention and climate mitigation in their communities. Opportunities for student action include working with urban rooftop farms to identify additional opportunities for reducing storm water runoff and developing 'greener' buildings in their city.

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References Baussan, Danielle. "Social Cohesion: The Secret Weapon in the Fight for Equitable Climate Resilience." Center for American Progress. May 11, 2015. https://www.americanprogress.org/issues/green/report/2015/05/11/112873/socialcohesion-the-secret-weapon-in-the-fight-for-equitable-climate-resilience/ Beatley, Tim. Biophilic Cities: Integrating Nature into Urban Design and Planning. Washington D.C.: Island Press, 2011.

"Buildings and climate change" (Fact Sheet). U.S. Green Building Council. Accessed November 22, 2015. http://www.documents.dgs.ca.gov/dgs/pio/facts/LA%20workshop/climate.pdf City of Toronto. “Green Roofs.” Accessed December 11, 2015. http://www1.toronto.ca/wps/portal/contentonlyvgnextoid=3a7a036318061410VgnVCM10000071d60f89RCRD#ind ustrial Cohen, Nevin. “Increasing the Resilience of NYC’s Food System to Climate Change.” Urban Food Policy. September 11, 2014. http://urbanfoodpolicy.com/2014/09/11/increasing-the-resilience-of-nycs-food-system-to-climate-change/ Cramer, Kristine. “Sewers, Streets, and the Transformation of Urban Neighborhoods.” Guest presentation, EDUC 536 Urban Ecology, Antioch University Seattle, WA. December 7, 2015.

Dubbeling, Marielle. "Urban Agriculture as a Climate Change and Disaster Risk Reduction Strategy." Urban Agriculture Magazine, 27. March 2014. http://www.ruaf.org/sites/default/files/UAM%2027Urban%20agriculture%20as%20a%20climate%20change%20and%20disaster%20risk%20reduction%20strategy.pdf Ezekiel, Siena et al., 2015. "Teaching Environmental Justice through DIY Projects." Final project presentation for EDUC 537: Building Capacity, Antioch University Seattle, WA, December 14, 2015.

Frith, Kathleen. 2007. "Is local food more nutritious?" (White paper). Harvard School of Public Health. Accessed December 16, 2015. http://www.chgeharvard.org/resource/local-more-nutritious Kang, Helen. 2013. "Food Insecurity Impacts on the U.S. Poor as the World Warms". Publications, Golden Gate University of Law, 615.http://digitalcommons.law.ggu.edu/pubs/615 Morello-Frosch et al. 2009 . “The Climate Gap: Inequalities in How Climate Change Hurts Americans and How to Close the Gap.” Program for Environmental and Regional Equity, USC Dornsife. Accessed online October29, 2015. https://dornsife.usc.edu/pere/climategap/ Pirog, Rich and Timothy Van Pelt. 2001. "Food, Fuel, and Freeways: An Iowa perspective on how far food travels, fuel usage, and greenhouse gas emissions" Leopold Center for Sustainable Agriculture. Accessed December 16, 2015. http://www.leopold.iastate.edu/pubs-and-papers/2001-06-food-fuel-freeways#sthash.kEyPKWWV.dpuf Ross, Tracy. "Community and Climate Change: How Social Cohesion can Help Low-Income Baltimore Neighborhoods Prepare for Disaster." TalkPoverty.org. August 4, 2014.

Wolf, K.L., and M.A. Rozance. 2013. "Social Strengths - A Literature Review. In: Green Cities: Good Health." College of the Environment, University of Washington. Accessed online December 2, 2015. www.greenhealth.washington.edu

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