dditionally, these warmer temperatures can cause precipitation to be more likely to fall as rain, affecting the snowpack in many parts of the country. Scientists have suggested that the Southwest is one of the most susceptible regions to drought. Drought events cause a positive feedback loop in which the warmer temperatures cause faster evaporation rates, leaving soils drier. As the drought continues, there is less cycling of water throughout the atmosphere, which prevents cooling on the Earth’s surface. The result of this lack of cooling is a continuation of the hot, dry temperatures making the drought even longer and more severe. In Arizona, the danger from climate change induced droughts in farming is the potential for crops to die from heat or drought intolerance, which is likely to negatively impact crop yield. Communities must learn how to adapt their gardens to the effects of climate change in their area as well as understand the importance of how local gardening helps to mitigate those same effects.
Gardening has a significant effect on greenhouse gases in comparison to mass production agriculture. One way that planting crops can decrease emissions is through the creation of a carbon sink. Essentially, these sinks created by plants store carbon dioxide and turn it into oxygen that is released into the air through photosynthesis. To break it down - plants obtain carbon dioxide and water from the air and through the use of light energy produce glucose, a type of sugar using the excess hydrogen atoms from the water molecules. The plants then convert the carbon dioxide into oxygen. Through this process, the plant is essentially converting a greenhouse gas into oxygen, an action that is incredibly helpful in reducing atmospheric carbon dioxide levels. The carbon within plants is stored in the plant’s roots, stem, and leaves until the plant dies. Some of the stored carbon returns to the atmosphere in the form of carbon dioxide as the dead plant decays, while organic carbon is transferred back into the soil in which the plant lived. This results in an overall decrease of carbon dioxide from the atmosphere throughout the plant’s lifetime.
Not only is gardening beneficial in terms of removing carbon dioxide from the atmosphere through photosynthetic processes, but personal gardening can help to reduce emissions of one of the most rapidly ozone-depleting greenhouse gases – nitrous oxide. Nitrous oxide is about 265 times more detrimental to the ozone layer than carbon dioxide and therefore contributes to global warming at a much faster rate.
Introduction of nitrous oxide into the atmosphere from human activities has increased by 30% since 1980. In the United States, 80% of human emissions of nitrous dioxide can be attributed to the agricultural industry – the majority of which come from nitrogen fertilizer usage. In the mass production of produce, farmers apply nitrogen fertilizers in excess to their crops in order to increase the amount of nitrogen microbes available within the soil, which in turn increases a plant’s production capacity. The excess nitrogen fertilizer not utilized by crops is converted into nitrous oxide by microbes in soils, which rises into the atmosphere. This enhances the greenhouse effect by depleting the ozone layer at a higher rate than many other greenhouse gases. The excess fertilizer can also become pollutants such as ozone and ammonia. This occurs when sunlight interacts with the nitrous oxide, separating the nitrogen and oxygen atoms, and these oxygen atoms combine with oxygen in the air to create ozone. These pollutants can be harmful to humans when stored in excess in the troposphere, the level of the atmosphere in which humans live. Excess pollutants can cause negative effects within human respiratory systems and can harm the Earth’s ecosystems by altering growth cycles.
Unfortunately, the release of excess nitrous oxide into the atmosphere is not the only negative effect of the use of nitrogen fertilizers in the agricultural industry, as the fertilizers pollute water runoff from farms, creating water pollution. After heavy rainfall events, excess fertilizer can wash into local water sources including streams and rivers, thereby contaminating the water with excess chemicals such as nitrogen and phosphorous. This nutrient pollution in ground water can cause harm to humans who use groundwater as a primary drinking source. Even at minimal levels, excess nitrates in drinking water can be extremely harmful to infants. Through a reduction of mass agriculture by an increase in personal gardening, there is less danger of nutrient pollution in local water sources for Arizona residents.
While the mass production of fruit and vegetables is far more sustainable than meat, the entire production process produces large amounts of greenhouse gas emissions down the chain from supplier to distributor to retailer to consumer. Comparatively, 50% of emissions from produce come from transportation, with only 10% of emissions coming from transportation for red meat. By gardening instead of purchasing mass produced produce, the transportation of produce to the eventual consumer is severely limited, which greatly reduces the amount of greenhouse gases released into the atmosphere. The transportation of fresh produce to your home generates a large amount of greenhouse gases, but this isn’t the only negative aspect to consider within the consumption of mass-farmed produce. The emissions generated from mass production also include the waste from packaging the items in plastic or cardboard as well as the food waste generated from damage to the items in transportation.
By gardening locally, this waste can be avoided – fruits and vegetables can be eaten right off of a tree or from the ground with no wasteful packaging or extensive diesel truck drives necessary to get the harvest to you. In addition, as a consumer of the produce you grow, you know that there are no chemicals or pesticides used in the production of your products, meaning that there are minimal emissions related to your garden.
The positive effects of gardening do not stop at the scientific benefits such as slowing greenhouse gas emissions from food production. Growing your own food is good for your mental and physical health, as well as for the community as a whole. Community bonding over food has been shown throughout history, and the 21st century is no different. A study by the University of Oxford found that communal eating and food sharing result in more bonded communities by increasing feelings of wellbeing and acceptance within a community. Sustainable communities can be defined not only in terms of physical sustainability – how well the community works to be energy efficient, reduce waste, or otherwise. They can also be viewed as socially sustainable. Community gardening promotes both types of sustainable communities by working with others or sharing the literal fruits of your labor that were produced under sustainable conditions.
Each crop has specific conditions under which it thrives – full sunlight and water every day, low light and watered once every three months, and anywhere in between. Areas such as Phoenix are considered ideal environments for desert plants that are considered to be “drought-tolerant”. Drought tolerant plants are ones that tend to thrive under hot and arid climates. These plants that are often bred specifically to thrive under minimal watering conditions often grow their roots much deeper into the soil in order to obtain as much water as possible. Additionally, other drought tolerant plants can grow faster than other varieties, meaning that they require much less water from the seed stage through development to a mature vegetable. Popular drought-tolerant vegetables include corn, quinoa, summer squashes, lima beans, and okra, among many others.
It is evident that the benefits of gardening are countless, not only on a personal and social level, but also on an environmental level. By gardening for yourself rather than supporting the agricultural industry, your actions are working to reduce the amount of greenhouse gases released into the atmosphere that are contributing to global warming. As these greenhouse gases decrease in concentration, the effects of global warming will be slightly lessened, helping to return Arizona to a more temperate climate with less climate-change induced drought. In addition, by gardening at home, you can ensure that you know exactly what is used in the growth of your produce and feel confident knowing that you are not contributing to nutrient pollution from excessive fertilizer use in mass farming. Lastly, gardening is a great way to get outside, learn more about the Earth, and allows you to enjoy a tangible result of your work within your own backyard. While climate change might be making it harder for gardens to thrive due to intense heat or drought, gardening can help to slow the effects of climate change through a reduction of overall greenhouse gases in the atmosphere. By adapting appropriately to the changing climate in Arizona, including the intensifying heat and drought, residents can continue growing thriving gardens in their community despite environmental challenges.
Hailey Weinberg is a graduate student at Northern Arizona University pursuing a Master of Science in Climate Science and Solutions with an emphasis in sustainability. With a background in climate change, environmental science, sustainability, and cultural competency, Weinberg has a strong interest in creating both socially and physically sustainable communities. Currently, she is working as a Community Climate Solutions Team Intern with 350 Madison, focusing on the limitations on local communities' sustainable development based on state policies, especially relating to the updating of building codes.
References:
[1] Climate change to make hot droughts hotter in the US southern plains - Welcome to NOAA Research
[2] Drought Tolerant Plants | Elgin Nursery & Tree Farm: Phoenix, AZ
[3] Drought-Tolerant Vegetable Garden - Veggies to Grow During Droughts (gilmour.com)
[4] Social eating connects communities | University of Oxford
[5] A comprehensive quantification of global nitrous oxide sources and sinks | Nature
[6] The Greenhouse Gas No One’s Talking About: Nitrous Oxide on Farms, Explained | Civil Eats
[7] Ch9_0923.pdf (cleanmetrics.com)
[8] The Issue | Nutrient Pollution | US EPA
