Soil is heading towards an "endangered" state! Experts say this fact must be incorporated into our collective consciousness in order to feed the 9 billion people by 2050!
Carbon is a key component in reversing soil degradation, but it's also the element that contributes to global warming. If we want to maintain a healthy diet and combat global warming, we must remember to "keep carbon in the right place."
The above conclusions were drawn from an international symposium on "Soil Carbon Sequestration" held in Reykjavik, Iceland at the end of May, involving 200 researchers from more than 30 countries.
"All life needs soil," said Anne Glover, chief scientific advisor to the European Commission. "While soil is invisible to most people, it provides an estimated $1.5 trillion to $13 trillion in services to the ecosystem each year."
The soil beneath our feet is a magical world, teeming with tiny, wondrous creatures. A mere handful of soil can contain 500,000 different species, including ants, earthworms, fungi, bacteria, and other microorganisms. She stated that almost all of our food comes from the soil, with only 1% originating from the ocean.
Soil sustains the life of plants worldwide, and plants are a primary source of oxygen—another vital ecosystem service. Soil purifies water sources, prevents pollutants from entering streams and lakes, and mitigates flooding. Soil absorbs a significant amount of carbon, second only to the ocean.
"It takes 500 years to form a two-centimeter-thick layer of fertile soil, but only a few seconds to destroy it," Graf said.
Every year, 12 million hectares of land degrade, land that could have supported 20 million tons of food. Over the past 40 years, 30% of the world's arable land has lost its productive capacity due to erosion. Unless we can quickly reverse this trend, it will be impossible to feed the world's growing population.
A report released by the World Resources Institute in late May indicates that by 2050, the world will need "more than 60% more food energy" than in 2006. The report concludes that achieving this goal while maintaining economic growth and environmental sustainability is one of the most important global challenges of our time.
Rattan Lal of Ohio State University stated that urban development is exacerbating the loss of arable land, with cities of 1 million residents occupying an average of 40,000 hectares of land.
Plowing and clearing crop residues after harvesting, along with overgrazing, leave soil exposed and vulnerable to wind and rain damage, gradually causing often-overlooked soil erosion. This is like the wear and tear on car tires; unless given the necessary attention and care, disaster is only a matter of time.
Soil erosion also releases carbon into the atmosphere, contributing to climate change. He stated that if good agricultural practices are followed, such as replacing tilling with sowing, planting mulch crops, and leaving crop residues, the soil can be transformed from a carbon source into a carbon solution.
When plants grow, they absorb carbon dioxide from the atmosphere and release oxygen. After harvesting, the more crop left behind, the more carbon is retained in the soil. This carbon is mainly found in humus (formed from decaying plants), which is rich in organic matter. Only 1.5% of carbon is needed to keep the soil healthy and resilient, and to better withstand harsh conditions such as drought.
However, most soils suffer from 30-60% carbon loss. "Soil is like a bank account. You should only withdraw the money you've deposited, but in most places, the soil is severely overdrawn."
Lal said that if farmers and ranchers receive the right support, they could create a “miracle”—helping to keep carbon in the soil and remove carbon dioxide from the atmosphere, while feeding the world’s population.
Ólafur Arnalds, a soil scientist at Icelandic Agricultural University, estimates that the world's 3.4 billion hectares of pastureland have the potential to sequester or absorb up to 10% of annual carbon emissions (primarily from burning fossil fuels and cement production). He states that while reducing overgrazing and adopting other pasture management techniques may decrease animal populations in the short term, this contributes to the long-term health of grazing lands. These practices offer numerous other benefits beyond helping to combat climate change.
However, this view has been questioned by many locals because accurately measuring how much carbon a farm or ranch can absorb from the atmosphere is full of variables and difficult to determine.
Guðmundur Halldórsson, a researcher from Iceland’s Soil and Water Conservation Agency and co-organizer of the symposium, said that proper land management can help address climate change, but a significant reduction in fossil fuel use is still necessary.
He pointed out that using farmland or pastures as "carbon sponges" creates various problems. He stated, "The real key is to adopt practices that promote soil health, thereby increasing its food productivity." He believes this approach is most likely to help improve local livelihoods, protect water resources, promote biodiversity, reduce soil erosion, and help return carbon to the land.
Halldórsson stated, "Iceland over-exploits its land, trying to squeeze more resources out of it, pushing it beyond its limits. We call this 'killing the goose.' We can no longer treat the land the way we used to."
Located in the North Atlantic, Iceland was covered in forests, lush grasslands, and wetlands when the first settlers arrived on this windy island nearly 1,000 years ago. By the late 1800s, 96% of its forests had disappeared, and overgrazing had destroyed half of its grasslands. Iceland became one of the poorest countries in the world, its people suffered from hunger, and its landscape became the largest desert in Europe.
Driven by the need for survival, Iceland pioneered technologies to halt land degradation and promote land restoration. For over 100 years, the Soil and Water Conservation Service has worked tirelessly, but with very limited results and slow progress. Today, at least half of what was once covered in forests and grasslands remains bare and severely eroded by strong winds.
Iceland is now far less reliant on agriculture than it used to be, and the painful lessons of past land mismanagement seem irrelevant to the 90% of Iceland's population living in urban areas. "The public doesn't support land reclamation," says Halldórsson, "we've forgotten that the land is the foundation of life."
Sources: Environmental Information Center (2013-06-28)
