Many people are well aware of how climate change has increased average global temperatures and fueled extreme weather, but few stop to ponder how climate change can affect soil quality.
The burning of fossil fuels is one of the biggest causes of climate change, and this is perpetrated by our reliance on non-renewable sources of energy like coal and natural gas for electricity, as well as petroleum-based fuels to power cars, trucks, planes, and trains. Burning these fuels releases greenhouse gases that trap heat in the atmosphere, causing temperatures to rise and disrupting longtime climate patterns. These gases are also absorbed by the ocean, which is warming and becoming more acidic as a result.
Here, we discover how climate change affects soil and what can be done to stop it.
Soil – A Carbon “Sink”
In certain parts of the world, higher temperatures caused by global warming may increase vegetation growth, resulting in higher carbon storage in the soil. This is because plants absorb carbon from the air, use much of it to fuel growth, and distribute the rest through their roots, which the deposit the carbon into the ground. If the soil isn’t disturbed, that carbon can remain trapped underground. That’s why scientists call soil a “carbon sink.” In fact, it is the second-largest carbon sink on the planet, behind only the ocean.
Plowing or tilling the soil releases that carbon into the atmosphere. This is what has occurred in the U.S. Midwest over the course of the past 200 years, beginning when European settlers arrived in the 1800s and started tilling the tallgrass prairie to farm wheat, corn, and other crops.
Different types of soil can store different amounts of carbon. Soils in warmer, drier climates typically hold less carbon, while peat soils contain the most. Peat is found in certain wetlands called bogs. It contains large amounts of partially decomposed plants, which are prevented from fully decomposing due to the high water saturation. Much like plowing the grasslands, draining peat bogs to reclaim land for agriculture or other uses releases carbon into the atmosphere. Without the water, oxygen can reach the partially decomposed plant matter in the peat, speeding up the decomposition process and releasing carbon.
Climate Change and Soil Carbon
Research has demonstrated that higher temperatures could increase the rate of decomposition of the organic matter in soil, which would cause the release of more carbon.
Higher temperatures and more frequent droughts could also cause some peatlands to dry out, allowing organic matter to break down relatively quickly and subsequently venting carbon into the atmosphere.
In addition, higher temperatures may melt the permafrost found in very cold Arctic and Antarctic latitudes. Permafrost is soil or rock that has been frozen for two or more years; some permafrost has been frozen for thousands of years. If this long-frozen soil thaws out, it would have the effect of releasing some or all of the carbon stored within. Melting permafrost would also release methane, another greenhouse gas that is locked in the soil in the form of frozen organic matter. This is especially alarming because methane is much more potent than carbon—it traps 20 times as much heat.
Scientists do not yet know exactly how much carbon and methane will be released from the soil as the earth warms, and exactly how much these emissions will contribute to future climate change. However, these scientific experts realize that it is a serious concern.
Other Effects of Climate Change on Soil
Climate change may also affect soil in other ways. For example, low-lying coastal areas are threatened by sea level rise as the polar ice caps melt. Some areas may literally be underwater one day, while others may experience a more subtle, but still serious effect from these rising seas. Ocean water can intrude into the fresh groundwater that people use to drink. This saltwater intrusion can decrease the quality of soil, rendering it less fertile.
Climate change may also affect soil via the more extreme weather patterns it is expected to cause. In some regions, this could include more frequent floods or more instances of very intense rainfall that could cause soil to become waterlogged and disrupt the organic matter it contains. Waterlogged soil also contributes to the huge problem of soil erosion, which not only poses a risk to humans living in nearby areas, but also disrupts or destroys natural habitats.
What to Do
Since soil is the second-largest carbon store, it’s important to understand the risk of climate change in relation to it. In addition, although soil is often an overlooked part of the environment, it’s also important to consider because fertile soil is necessary for growing the food we eat, and for supporting healthy ecosystems.
The only real solution for the climate change problem and its impact on soil is to drastically reduce our dependence on fossil fuels. By making efforts to increase our use of alternative fuels and by educating people, we may be able to avoid some of the worst effects of climate change.