Microbes are key to the Earth’s climate system. They can have a massive effect on the planet, but human activities can also influence them, meaning that microbes can be both drivers and mitigators of climate change. When properly utilized, microbes could be the key to reducing global warming and stopping positive feedback loops. Here are the basics of the relationship between microbes and climate change:
How Microbes Affect the Planet
As stated above, microbes both drive climate change, meaning they can speed up the process of climate change by releasing greenhouse gases, and mitigate climate change, meaning they slow down the process of climate change by absorbing greenhouse gases.
Drives
There are certain processes that simply produce greenhouse gases, like when microbes in the soil break down plant- and animal-derived organic matter and release CO2. However, many of the ways microbes can drive climate change are because of human activities. Farming livestock is a big source of greenhouse gases for a couple of reasons, one being that livestock like cows have bacteria in their stomachs that produce methane, which gets released into the air. Previously frozen ground, like in Arctic wetlands, thaws as the temperature rises. Microbes will begin to break down the previously frozen organic matter, releasing CO2.
Mitigations
But don’t worry, microbes also have processes to mitigate climate change. Certain bacteria consume methane as an energy source and emit it as CO2, changing a gas with a high warming potential to one with a lower warming potential. Scientists are researching ways to harness these microbes to reduce emissions, such as placing methane “bio-filters” close to sites with a high methane output, like coal mines and landfills. They have also developed ways to lower the methane emissions from livestock, like dietary changes, genetic engineering to alter gut microbiomes, and vaccine development targeting methane-producing microbes.
Soil microbes play a huge role in creating stable soil organic matter, which can hold carbon in the ground for long periods of time. Managing soil microbiomes can enhance how much carbon can be sequestered in the ground and kept out of the atmosphere.
The ocean version of soil microbiomes is the microbial carbon pump, a process in which microbes change labile dissolved organic carbon into recalcitrant dissolved organic carbon, which can be stored at the ocean floor for decades to millennia.
How Climate Change Affects Microbes
Microbes are incredibly sensitive to environmental changes. Climate change can change everything from microbe processes to which microbes dominate the ecosystem. Microbes like soil bacteria have been observed to evolve in response to climate change, like warming over relatively short timescales. Warming oceans could also become a source for greenhouse gases as microbial metabolisms change and become warmer, reversing the work of marine sinks (as discussed above).
Feedback Loops
Because of the effect climate change has on microbes, these microbiological systems can create feedback loops. Let’s use the thawing Arctic wetlands as an example:
As the arctic warms, the snow and ice that used to cover the surface begins melting. This means that more water and land become exposed, which leads to more heat from the sun getting absorbed into the ground. Any organic material that was frozen is now getting thawed, and microbes begin the decomposition process which releases CO2 into the atmosphere. Now there are more greenhouse gases, and the ocean begins to warm more, which causes more ice to melt, and the cycle continues.
This same principle applies to soil, where warming soil increases decomposition rates.
Why Does it Matter?
Although microbes are important, they are complex and are not always included in large-scale climate models successfully. Because microbes have the potential to drive and mitigate climate change, failing to account for microbiological processes may lead to underestimated risks.
Understanding microbiological processes is imperative to keeping the planet in balance. Microbiologists have made many breakthroughs to help process more greenhouse gases, utilizing microbes and natural processes to restore balance to the Earth.
Citations:
American Society for Microbiology — How Methanogenic Archaea Contribute to Climate Change
University of Utah — How Microbes Can Combat Climate Change
WIREs Water — Research Article on Microbes and Water
WWF Arctic — Climate Change
Wikipedia — Microbial Carbon Pump
University of California, Irvine — Soil Bacteria Evolve with Climate Change
American Society for Microbiology — Policy Recommendations to Address Climate Change