This past summer, July 2023 went down in history as the hottest month ever recorded.The impacts of climate change on our world are getting harder to ignore, and farmers are on the frontlines both in experiencing that impact firsthand and holding a piece of the puzzle to a brighter path forward. Now is the time to understand – and prepare for – the effects that a changing climate can have on our farms and waterways.
To start, climate change makes droughts longer, more severe, and more frequent (U.S. Geological Survey). We’ve already seen evidence of this in the past few years with an increased number of major droughts per year (NASA).
These droughts can impact the application and efficacy of pesticides, herbicides, and other chemicals used in conventional farming. During hot and dry weather, pesticides are more likely to drift from the target area where they were applied. The spray droplets evaporate faster in these conditions, leaving behind smaller droplets that are more likely to end up in non-target areas, including waterways (Oregon).
Furthermore, some pesticides need moisture to work, which renders them less effective during drought, and can also contribute to drift (Oregon). Over time, pesticides tend to break down into less toxic chemicals through processes such as hydrolysis and microbial breakdown, but drought hinders these processes. This means that pesticides will accumulate if they are continuously sprayed during drought (Oregon). It’s evident that during periods of drought, pesticides are less effective and have more potential to cause harm.
Luckily, there are farming methods that entirely avoid these issues during droughts and beyond.
Rodale Institute’s Farming System Trial has been studying side-by-side plots of conventional and organic cash crops for more than 40 years. They found that during most years, the conventional and organic manure systems matched each other for yield. But during a notably dry year, the organic manure system produced a significantly higher yield. As droughts become more frequent, organic practices stand out as a clear avenue to avoid both the limitations and dangers of pesticides.
Organic practices are also standing out as pests are becoming resistant to pesticides and weeds are developing resistance to herbicides. Pests who have been exposed continuously to the same pesticide can undergo natural selection that allows the surviving population to continue to survive when the pesticide is applied. Pesticide resistance is becoming more common, which causes problems for farmers and poses higher risks of contamination to the environment and to people (University of Nebraska-Lincoln).
Unfortunately, climate change is also expected to make pest problems worse. As temperatures rise and precipitation patterns change, pest populations and their geographic locations are expected to change, giving farmers new challenges (USDA). Increased levels of CO2 in the atmosphere also encourage the growth of weeds (USDA).
This combination of decreased effectiveness of pesticides and worsening pest problems means that pesticide usage is expected to increase in the coming years (PANNA). This is not only ineffective, but also carries devastating implications for our waterways.
Around half a million tons of pesticides are applied to US farmland each year, and runoff and infiltration brings pesticides into our streams, rivers, and groundwater (U.S. Geological Survey). This poses dangers to fish and other wildlife and can even impact our drinking water (U.S. Geological Survey).
Supporting local organic farms is one of the best ways consumers can show support to farmers and protect our waterways in the face of climate change. If you are a consumer, make it a priority to buy local organic produce when and where you can.
If you are a farmer, consider transitioning to an organic farm – or even make a start by adopting a few organic practices and reducing your pesticide usage. If you do find yourself using pesticides in a time of drought, this advisory contains advice to minimize harm during application.