The ways that humanity has been producing food have been developed under fairly stable climate conditions. However, with a warming world, we will see many impacts to the established agricultural system. Some of these impacts are already being seen today, but may become much worse if we continue down a path of “business as usual” with our consumption of fossil fuels and natural resources.
- Shifts in precipitation patterns, leading to increased droughts and flooding
As the planet warms, precipitation is predicted to increase at higher latitudes and decrease in the topics and the subtropics .
In many places, drought is already becoming the norm, dramatically reducing water availability for crops, and increasing irrigation requirements. In existing arid regions, it may be difficult to adapt the cultivation of crops to even more drought and increased temperatures.
In areas experiencing an increased number of downpours, increased flooding can wipe out an entire crop with a single storm event.
- Water runoff and erosion
With increased precipitation and downpours, it can be difficult to store the excess runoff water volumes in the ground that would otherwise be used for crops. This excess water runoff also erodes precious topsoil that is needed for growing crops.
- Increased pests and disease
In a warmer world, there is likely to be an increased vulnerability of some crops to problems like fungal diseases and insect pests that will stick around longer during a longer growing season .
- Shifting of growing regions further north and increased heat waves
It has been found that hardiness zones have been shifting further northward in the Northern Hemisphere during the last several decades as temperatures have increased . The incidents of heatwaves each summer is also increasing globally .
The shifting of hardiness zones will likely mean that crops that have always been grown in a given region may no longer be able to grow well there in the future with warmer temperatures. However, such crops may still grow well in areas further north where it is cooler .
- An increase in extreme weather events
An increase in extreme weather events such as strong tropical storms and tornadoes, may destroy crops much more frequently .
- Changes in the growing seasons
Although an extension in the growing season due to an earlier spring and a later fall might increase the productivity of some crops, the increased opportunities for droughts, floods, storms, diseases, and insects due to climate change could override some of these potential gains in productivity of a longer growing season.
- Decrease in food security
In existing arid and tropical regions, increased temperatures, heat stress, and increased water loss through evaporation may make growing crops using traditional methods even more challenging.
- Flooding of agricultural fields along low-lying areas
Due to an increase in sea levels, low lying coastal agricultural areas are expected to experience more flooding. As sea levels continue to rise, groundwater supplies that are used for agriculture may become increasingly salinated and unsuitable for agriculture .
- Melting Glaciers
As average temperatures continue to increase, there will be an increase in water flow from melting glaciers around the world, potentially leading to the flooding of agricultural areas near glacier-fed rivers. Once glaciers have significantly retreated, populations that depend upon glacier-fed waters are likely to experience decreased water flow and drought, leading to negative impacts on agricultural productivity .
Possible areas of agricultural adaptation and innovation due to climate change
In a warmer world, farmers will likely need to change the varieties of crops that they grow, as well as their farming methods.
Some possible agricultural adaptations to climate change include:
- Growing heat-sensitive crops further north in the Northern Hemisphere and further south in the Southern Hemisphere in cooler regions.
- Growing more heat-tolerant crops and more perennial crops such as through the application of permaculture.
- The reduction or elimination of water-thirsty crops, such as rice.
- An increase in the use of water conservation methods such as drip irrigation.
- A dramatic reduction or elimination of fossil fuel use in agriculture, as agriculture is currently a large user of fossil fuels, which contributes to climate change.
- The localization of food systems and the growing of food indoors to increase agricultural resilience in the face of a changing and unpredictable climate.
Despite the many agricultural challenges that we are facing in a warmer world, we have a tremendous opportunity to transform our food system into a much more sustainable world and if we act swiftly and decisively today, we may be able to avoid the worst of the predicted climate change impacts on agriculture in the future.