My grandfather is a farmer. When I was little, he always tells me, “To become a successful farmer, 30% depends on oneself and the other 70% depends on the weather.” At the time, my grandfather probably had nothing in mind about the impact of global environmental change on agriculture. But he also clearly did not realize how his own practices could change the environment and the weather pattern that the farm relies on.
Broadly speaking, there are two main categories of negative impacts that could occur during agricultural practices:
- Biotic – including greenhouse gases, introduced species, genetically modified organisms and animal management.
- Abiotic – including pesticides, fertilizers, heavy metals and land management.
Among different types of pollution, I would like to pinpoint two major sources that have the biggest impact in terms of their significance and scale.
The first area to be discussed is greenhouse gases (GHGs). The term refers to gases that have a warming potential, absorbing infrared radiation, thus trapping holding heat in the atmosphere.
Carbon dioxide (CO2) is the most prominent GHG that scientists are concerned about because of its relative abundance and long lifespan. CO2 is also commonly used as the standard GHG when we measure emission from different sources.
It is important to understand that GHG is present naturally throughout earth history. However, since the pre-industrial time, the GHG has increased in an exponential way that scientists have relate this sharp increase with anthropogenic practices.
Now, we understand the CO2 is the main driving force for climate change. Let’s take a close look at how agricultural practices are contributing to the GHG emission portfolio.
According to IPCC, agriculture sector accounts for 24% of the global GHG emission, only 1% lower than the leading energy sector. Within that, United Nation Food and Agricultural Organization (FAO) estimated that 18% of anthropogenic GHGs emission are directly and indirectly related to world’s livestock.
Yes! As you saw, the GHG generated from fecal waste along is already bigger than the Transportation sector. When we have heated discussions on moving to electric cars and more efficient transportation, more efficient agricultural practices could potentially have a larger impact on mitigating climate change.
The second area to be discussed is fertilizer usage. Whether it’s natural fertilizer or artificial fertilizer, this kind of product is commonly used to supply more nutrients essential to the plants.
Despite fertilizers could typically increase yields of a certain product, the production of fertilizers could generate GHG and nitrogen fertilizers can be converted to nitrous oxide, a greenhouse gas. In addition, the efficiency of fertilizers is very low, and the remnants would pollute the soil and water body.
When excessive nutrients go into water body, a serious ecological consequence — eutrophication could occur. The enrichment of water would reduce oxygen level, resulting in hypoxia. One of the most upfront example right now is the “dead zone” in Gulf of Mexico. Due to the huge farm&city nutrients influx from the Mississippi River, the ecology in the Gulf of Mexico has been devastated.
To mitigate the ecological impact along the Gulf, collective effort from industries and farmers must be taken. A more efficient and sustainable utilization of fertilizers is an urgent matter for our Earth.
While climate change is affecting agriculture is many ways, it is crucial to retrospectively pay attention to the global impact farms made. Polycentric effort is needed to combat the unprecedented global environmental change we are facing today.