The climate on Earth depends a lot on the exchanges between the soil and the atmosphere. Globally, there are currently 2.5 trillion tonnes of carbon stored in soils, which is two to three times more than in the atmosphere. What are the consequences of global warming on soils?
There are currently 2.5 trillion tonnes of CO2 stored in soils (mainly in the form of organic matter), which represents two to three times more than in the atmosphere.
Increasingly rising temperatures risk increasing decomposition and mineralization of the organic material in soils, thereby reducing the organic carbon content. Let’s imagine that all this C02 starts to be released …
What are the consequences of global warming on soils?
The first thing is that climate change could accelerate the risk of land degradation and its main properties. This could impact the capacity of soils to support ecosystems, which would further worsen the impacts of human pressure.
Global warming could therefore have multiple consequences on soils, each more dramatic than the next.
1. Water regulation
Soils are involved in the water cycle. The quality of the soil determines the proportion of water that runs off and that which infiltrates. Soils thus regulate the water table filling, as well as the regime of watercourses.
If the temperature of the soil increases, the water may evaporate more and there will therefore be less water to replenish the water tables and supply the rivers.
In addition, water infiltrating less on dry soils, this increases the risk of runoff and therefore of river floods and floods.
2. Floods
Healthy soil can prevent us from flooding. Especially with crops that limit erosion and capture water. Conversely, hard-coated surfaces, such as the bitumen that covers the arteries of our cities, waterproof floors. They promote water runoff. Urbanization is therefore an aggravating factor for flooding.
3. The melting of permafrost
The melting of permafrost, this permanently frozen layer of the subsoil, present under Alaska, Siberia or the Arctic region, is another threat that has already become a reality. When it melts, permafrost releasesimmense amounts of CO2 in the environment, which further accelerates global warming and the unfortunate consequences for ecosystems.
Some scientists are also warning about another equally terrible risk: the melting of permafrost can also release viruses and bacteria dormant for hundreds or even thousands of years.
4. Coastal erosion
Climate change is accelerating coastal erosion rates due to rising sea levels and the increased frequency of storms and extreme events.
Some ecosystems, such as dunes and salt marshes, provide natural buffers to help withstand severe storms.
Residents of all potentially affected coastal regions are encouraged to maintain the natural capacity of the beaches, dunes, cliffs and salt marshes of move towards the earth as the sea level rises.
5. When soils sink or crumble
Faced with the central question “What are the consequences of global warming on soils?” », Many studies also draw attention to the risk of ground movements and soil collapse due to the destabilization of underground cavities.
Global warming is not the only cause, but it is it that accentuates the drought phenomena that destabilize the soil. The other responsible is, unsurprisingly, the man who (as usual) depletes resources of the planet, starting with groundwater reserves.
One of the most emblematic examples is Tehran, the Iranian capital with 13 million inhabitants including some parts sag from 25 centimeters per year. The reason ? By drawing water from its basement, the city depletes the water tables located under its foundations.
Read also:
The consequences of ocean warming
The consequences of melting glaciers and sea ice
The impact of global warming on soils
What does a temperature increase of + 2 ° C mean?
Climate Café: the 11 episodes
Mexico is also experiencing spectacular sagging 8 cm per year. The city was built on an ancient lake which is based on soft and very unstable clays. The city’s cathedral has been undergoing consolidation work for several years …
Accelerating global warming opens bleak prospects for the future of many other cities in the world. Under the combined effect of land subsidence and rising water levels, some are already doomed to disappear before the end of the century.
This is particularly the case of Venice which sinks 0.8 to 1 cm per year. South of the United States, Miami and the New Orleans also risk being submerged by water before 2100, according to a study published in 2015 by the American Academy of Sciences.
What are the consequences of global warming on soils? Now you have a little idea …
