Climate Change and the Hidden World Beneath Our Feet

When people think about climate change, they usually think of events and transformations that are visible on the Earth’s surface, melting glaciers, floods, reduced crop yields, forest fires, and extreme heat. However, one of the most profound and less visible consequences of climate change is unfolding beneath the ground, within the soil. Although soil appears quiet and lifeless, it is actually one of the most dynamic and vital components of the Earth’s ecological system. Recent scientific research indicates that climate change is predicted to reduce what is called belowground ecosystem multifunctionality, meaning the soil will gradually lose its ability to perform several essential ecological functions simultaneously. This decline poses a serious threat to global environmental stability, food systems, and the climate itself.

Belowground Ecosystems

To understand why this is alarming, it is important to know what exists below the surface of the Earth. Soil is not just dust or dirt; it is a living system. A small handful of healthy soil contains billions of microorganisms such as bacteria, fungi, and tiny invertebrates, along with plant roots and organic matter. These components interact continuously and form a complex ecological network. Their combined activity influences decomposition, nutrient cycling, plant growth, water storage, and carbon sequestration.

When these processes are functioning smoothly and simultaneously, we say the soil has high multifunctionality. This means the soil is able to support plant life, store carbon, regulate water, enrich nutrients, and maintain underground biodiversity all at once. It is this multifunctionality that keeps ecosystems stable and productive.

How Climate Change Disrupts Soil Functions

Climate change alters the physical and biological conditions under which soil organisms operate. Rising temperatures speed up the decomposition of organic matter. At first, this may seem beneficial because it releases nutrients rapidly. However, over time, this leads to more carbon escaping into the atmosphere than being stored in the soil. The soil gradually loses structure, fertility, and the long-term ability to support plants.

In addition, changes in rainfall patterns make conditions unpredictable. Some regions are becoming wetter, causing nutrients to leach away, while others are becoming drier, reducing soil moisture needed for microbial and root activity. This weakening of the underground biological network ultimately reduces the soil’s multifunctionality.

The 16.4°C Threshold: A Critical Turning Point

A very important finding from recent research is that there appears to be a temperature threshold of approximately 16.4°C average annual temperature beyond which soil multifunctionality declines sharply. Below this temperature, soil ecosystems remain comparatively stable. However, when temperatures exceed this threshold, the balance shifts dramatically. Microorganisms break down organic matter much faster, carbon is lost to the atmosphere, and soil structure begins to deteriorate. In other words, once warming crosses this point, soils begin to lose their ability to perform multiple functions effectively.

This threshold is very meaningful because many regions are rapidly approaching or surpassing this temperature with ongoing climate warming. The changes that may follow will not be easily reversible.

Cold Regions Are Particularly Vulnerable

One surprising but serious consequence is that cold and high-latitude regions, such as the Arctic, Canadian tundra, northern Russia, and Siberia, are the most vulnerable to decline in belowground multifunctionality. These regions currently hold enormous reserves of carbon locked in frozen soil layers known as permafrost. Because cold temperatures naturally slow down decomposition, nutrients and carbon have accumulated in these soils for thousands of years.

However, as climate change leads to warming, this frozen soil begins to thaw. When permafrost melts, the organic matter inside it decomposes rapidly and releases large amounts of carbon dioxide and methane into the atmosphere. These gases contribute further to global warming, which accelerates more thawing in a dangerous feedback loop. This means a warming climate can trigger self-reinforcing soil degradation, making the situation worse over time.

Tropical and Dry Regions: Different Challenges, Same Threat

In contrast to cold regions, tropical regions already lose nutrients rapidly due to heavy rainfall and fast decomposition. Dry regions, such as deserts, suffer from very low microbial activity due to a lack of moisture. While the effects of climate change in these areas may differ in form, the result remains similar: soil becomes less capable of supporting plants, storing carbon, and maintaining ecological stability.

Implications for Food, Water, Forests, and Climate Stability

The decline in belowground multifunctionality has broad consequences for human life. Croplands depend on soil fertility for food production. If soils lose nutrients and structure, agricultural yields may fall. Forests, which regulate climate and support biodiversity, will struggle to regenerate if soil functions weaken. Water systems could also be affected, because healthy soils act like sponges, absorbing water and filtering pollutants. If soils degrade, floods and droughts will become more severe, and clean water availability may decline.

On a global scale, reduced carbon storage in soils will accelerate climate change, intensifying the very warming that caused the soil degradation in the first place.

        The predicted decline in belowground ecosystem multifunctionality is a silent but deeply significant environmental challenge. Soil is the foundation of life. If it loses its ability to perform essential ecological functions, the impacts will cascade through food systems, forests, water cycles, and climate stability. Protecting the soil, therefore, is not only a matter of environmental responsibility but also of ensuring the survival and well-being of future generations. Addressing climate change, conserving fragile ecosystems, and adopting sustainable agricultural practices are crucial steps toward safeguarding the unseen world beneath us, and, ultimately, the world we live in above it.