When discussing the notion of global warming, a considerable amount of focus is given to the role of greenhouse gases in trapping heat and driving the climate crisis. A question that is sometimes overlooked is whether greenhouses themselves have an impact on global warming. More specifically, do the emission of greenhouse gases from greenhouses contribute to the overall problem of the Earth’s rising temperatures?
According to the United Nations Food and Agriculture Organization, in 2018 global agriculture was responsible for approximately 11-12 percent of the world’s total emissions of the six main greenhouse gases, namely nitrous oxide, carbon dioxide, methane, halogenated gases, ozone and water vapor. Of these, the gases responsible for much of the heat trapping emitted by greenhouses are carbon dioxide, methane and nitrous oxide. In addition to artificial sources of greenhouse gases, such as from the burning of fossil fuels and agricultural waste, natural sources of these gases, including living organisms and soils, also play a part in the overall burden. Interestingly, the amount of greenhouse gas emissions from greenhouses pales in comparison to the estimated emission from livestock – around 18 percent according to the UNFAO.
Greenhouses, although depending on the specific structure, are insulated shelters designed to reduce the impacts of the external environment, thus enabling crops to be grow year-round. While the current industrial-scale usage of greenhouses has been a major contributor to solving issues relating to food sustainability and security, this practice has its own attendant issues, one of which is the rise of greenhouse gas emissions. Studies have found that greenhouses generate approximately three times more emissions than state-of-the-art farms when compared to outdoors crops. This is due the the energy-intense environment and processes taking place in greenhouses. For example, the electricity required to power equipment, such as ventilation and circulation fans, pumps and boilers, is made possible by burning of non-renewable fossil fuels and is a major contributor to elevated greenhouse gas emissions.
To answer the question as to whether greenhouses cause global warming, the answer is both yes and no. As outlined, greenhouse gases are an integral part of the climate crisis and studies indicate that greenhouses contribute a small but significant portion of these gases. However, the problem of global warming is multi-faceted and complex and the solution does not necessarily lie in ditching greenhouses and reverting to outdoor agriculture. Rather, the way forward is to focus on developing new and innovative technologies that can, for example, reduce energy consumption, thus decreasing emissions produced. Furthermore, greenhouses also offer considerable advantages, such as increased crop yields, healthier produce and reduced water consumption, as well as being crucial in meeting the food security challenges posed by an increasingly growing global population. Therefore, greenhouses should no be seen as the villain of global warming but rather as an important part of a holistic approach for tackling the climate crisis.
In conclusion, greenhouses do have a role in global warming, albeit a small one. As we move into an era where the focus is more and more being placed on finding ways of mitigating climate change, solutions must involve developing the technology used in greenhouses in order to reduce emissions, while at the same time, not dismissing the good they are doing to farms and food security worldwide.
