Classroom Module
carbon stocks and flows

Climate Change Mitigation and Food Justice

Industrial smoke stacks; power plants; exhaust from cars, trucks, ships, trains and airplanes typically get listed first when someone is asked to identify human-generated sources of greenhouse gases (GHGs). Other less obvious sources include land use (e.g., how we grow food, build cities) and land cover (e.g., soil, impermeable concrete paving, crops, pasture or forests).

The 2014 U.S. Global Change Research Program’s Third National Climate Assessment includes chapters with key messages about land use and land cover, agriculture, forests, cities and infrastructure. The sector referred to as Agriculture, Forestry and Other Land Use (AFOLU) emits approximately one quarter of anthropogenic GHG emissions. Choices about land-use and land cover often have major impacts on the degree to which human communities are vulnerable to climate change.

Better land-use and land management choices can help reduce atmospheric greenhouse gas levels.  This point is abundantly clear in the case of the Amazon, where dramatic declines in deforestation have averted megatons of carbon emissions thanks to a convergence of new institutional arrangements, regulations, political will, land use monitoring, social pacts and social change and supply chain monitoring (Hecht 2014).

The installation of community gardens and Food Forests in places where people live in poverty and lack access to fresh fruits and vegetables (i.e., food deserts) creates opportunities to foster food justice by driving socio-ecological change that is civically engaged and climate friendly. An urban Food Forest---which is really an agroforest is a land management system that replicates a woodland or forest ecosystem using edible plants, trees, shrubs, annuals and perennials. Fruit and nut trees provide the forest canopy layer; lower growing trees and shrubs create an understory layer; and combinations of berry-producing shrubs, herbs and edible perennials and annuals make up the shrub and herbaceous layers. Other companions or beneficial plants, along with soil amendments, provide nitrogen and mulch, hold water in the soil, attract pollinators, and prevent erosion.

By recreating the functions of a forest ecosystem, a Food Forest improves air, water, and soil as it creates habitat, harvestable food, and greenspace in the densest urban areas or campus environments. Trees, plants and soil stabilize nitrogen, reduce soil erosion and stormwater runoff, sequester carbon, and remove harmful pollutants. As urban green spaces, Food Forests reduce urban heat island effects and give residents a visual and physical respite from the impacts of urban living. Amended and re-planted soils produce a healthy soil microbiome, which supports more nutrient-dense foods and sequesters carbon. Pollinators, beneficial insects, and birds also find habitat in a Food Forest.

R. Lal and B. Augustin (eds.), Carbon Sequestration in Urban Ecosystems, 43
DOI 10.1007/978-94-007-2366-5_3, © Springer Science+Business Media B.V. 2012


Learning Objectives

What is the total reservoir of carbon in biomass and soils right now?•What is a carbon sink?
How do the above questions raise and address issues of food justice. How might a biomass and soil perspective in urban settings help clarify the potential value of urban agriculture.
  • We need to sequester about 500 to 1000 billion tons of CO2 (or about 150 to 300 billion tons of Carbon) by 2100. 
  • Can we help meet that objective through ecosystem management and restoration (Forests; Soils; Avoided food waste; etc).

Biomass and soil absorb carbon from the atmosphere and can play an important role in easing the massive environmental problems caused by climate change.


Renowned climatologist V. Ramanathan from the Scripps Institution of Oceanography makes a moral argument for mitigating climate change, arguing that it is caused by a fraction of the world's population but is affecting everyone on this planet. He urges scientists and policy makers to reach out to religious leaders, as he has done with the Pope and the Dalai Lama, and ask them to join together in pursuing solutions for the common good. (#30488). Watch the video and form your own judgement about this. Might a closer relationship among scientists, religious leaders and policy-makers help promote more climate friendly food systems and food justice?