With Europe’s deadly summer heat wave still fresh in mind, scientists from around the world are flocking to Glasgow to focus on the vital role soil plays in maintaining a healthy ecosystem and curbing climate change, writes Nan. Spowart
The World Soil Science Congress being held in Glasgow could be instrumental in the global fight against climate change.
While the burning of fossil fuels is responsible for two-thirds of harmful emissions, land misuse accounts for the other third, but it doesn’t get the attention it deserves, according to NatureScot’s Clive Mitchell.
He hopes that will change as a result of the Congress, which he describes as a “huge blow” for Glasgow, as it will be the first time the four-year event has been held in the UK since 1935, when it took place in Oxford.
Congress, July 31-August 5 at the SEC, will host some 1,600 scientists in the city and Mitchell believes it presents a huge opportunity to bring the soil into the spotlight and make it more central in the journey toward zero. liquid.
“The importance of soil is very much hidden and it’s time to drag it out and light it up,” he said.
Perhaps because it is under our feet, we forget that the soil is vital for human life on earth. “We wouldn’t be here without it,” Mitchell said. “Soil is very much at the heart of the climate/nature crisis we are currently facing, but it’s a very Cinderella issue in terms of its profile in pretty much everything we do, whether it’s talking about conservation, agriculture, forestry, highland management, development in towns and cities and so on.”
Soil should, in general, absorb carbon, but it is currently a net source of emissions globally and in Scotland. This is because humans have broken the global carbon cycle by burning fossil fuels (about 70%) and changing land use (about 30%).
Peatlands are drained and degraded, deer suppress peatlands and forest restoration, forests are mainly commercial plantations, cattle pastures are mainly fed by synthetic fertilizers, lowlands are mainly monocultures by heavy machinery with most of the trees and hedges removed, floodplains are prevented from flooding, urban areas have little green space, especially in poorer areas, coastal habitats such as salt marshes, seagrass and algae have been reduced, and the seafloor is largely disturbed . The landscapes are largely simple.
As a result, carbon that would normally be stored for hundreds or thousands of years in soils and sediments, or millions of years in fossil fuels, is returned to the atmosphere in a matter of years. For the climate, these releases are catastrophic.
Land-based emissions result from the systematic degradation of ecosystems through progressive simplification from more biodiverse to less biodiverse systems, including monocultures and drainage, especially from carbon-rich wetland soils.
Healthy, diverse and functional soils are essential for a healthy climate-nature system.
Mitchell points out that to reach net zero and maintain it, we have to fix the “green and blue” parts of the carbon cycle.
Fixing the “black” part (fossil fuels) is vital, but no amount of heat pumps or electric vehicles will fix the green and blue parts, so we have to transform the way we use all land and sea for agriculture, fishing and forestry. .
In Scotland, soils are a large carbon storehouse, containing over 3 billion tonnes of carbon, of which 53% is in deep peat bog soils. That’s about 60 times the amount of carbon held in the country’s trees and plants, making soils the main terrestrial store of carbon – and it’s important to keep it there.
In Scotland, around 30-40% of the transition to net zero will be concerned with land.
“Not burning fossil fuels is vitally important, but it only takes us two-thirds of the way to net zero and the other third is in how we use land and soil,” Mitchell said.
“This is a really important point to recognize if we are going to make our contribution to reaching the lower limit of the Paris target of 1.5-2oC. That’s where the Scottish government’s ambition lies, rightly so, but it will require major transformations in the way we use land to become a net carbon sink.”
One way or another, the use of land and sea will change. If the world chooses a +2oC world – and it is a choice – the changes are largely beyond human control, driven increasingly by the impacts of a changing and chaotic climate, imposing increasing costs of loss and damage on people and to the planet.
However, in a 1.5oC world, the changes are more in human control. This “no regrets” path is by far the least costly for people and the planet. Following this path requires rewetting and restoring peatlands, while making commercial and conservation forests more diverse and resilient.
Agroforestry would be the norm, with more hedges and trees on farmland, and intercropping to control pests. Farms would mix crops and graze cattle extensively, riverbanks would be forested, and floodplains would be inundated.
There would be more green space in cities to manage surface water, valuing local nature and sequestering carbon. There would also be more extensive and diverse marine habitats and less seafloor disturbance to ensure productive fisheries and more resilience in marine biodiversity in long-term recovery from acidification. Sea levels would continue to rise, but both coasts and rivers would be recognized and managed as dynamic systems.
Some examples of current practices show that there is potential for transformation, such as the Scottish government’s Peatland Action program and many examples of farms using regenerative practices – that is, those that improve soil health, increase biodiversity and sequester carbon through use of practices such as cover crops, crop rotation, minimal tillage, organic fertilizers, agroforestry and crop-livestock integration.
However, it must also be recognized that land and sea use must not only contribute to and maintain net zero, but must also be resilient to unavoidable changes.
These consequences include increased frequency and intensity of floods, fires, droughts, pests, diseases and pandemics. A changing climate impacts nature and its associated services the more severely the simpler and more degraded it is.
Soil health and more diverse nature not only build resilience to these events, but also make them less likely, correcting disruptions in carbon, nitrogen and other important cycles.
“Agriculture, forestry and the diversity of species we use to grow food are key to building resilience to the impacts of climate change, which of course include pathogens and diseases in natural systems, cropping systems and forest systems, as well as human systems – such as seen recently with the pandemic,” Mitchell said.
“Our current food systems are producing foods that are high in sugar, fat and energy, which are not very good for the health of the population and depend on production systems that are degrading soils and nature and contributing to climate change.
“We need to change so much
how much we eat so that our diets contribute to the health of the population and the planet.”
Mitchell maintains that there is room for meat in a net zero world, but it would have to be a production system more focused on the integration of livestock and arable systems, with more emphasis on organic fertilizers and at the same time adapting the breed to the capacity of the land. . In a Scottish context this might mean using efficient but smaller breeds.
The environmental cost of production must also be reflected in the price, according to Mitchell.
“There is really important work to be done in marrying sustainable production with sustainable consumption,” he said.
“This relationship between the price of goods and the cost to society and the planet is of vital importance.
“To avoid leakage problems, you would have to ensure that there was a carbon tax applied at the borders for carbon-intensive goods, so that it covers both things produced in the country and imports.
“This reduces the risk of leakage so you don’t have goods produced at an environmental cost competing with sustainable household products.”
Mitchell believes Scotland has a good story to tell in Congress.
“We have world-leading experience in people like Professor Pete Smith at the University of Aberdeen, who is the lead author on the Intergovernmental Panel on Climate Change for his work on soils and land use,” he said. “And Scotland is leading efforts to restore peatlands.
“The Scottish government has invested £250m into this over ten years and it is widely recognized that this is a good start, although we will likely need to double this by 2030 and find ways to attract private funding to match or exceed the amount of public money that is coming in..
“However, we now know how to restore them and create conditions to secure private money in a much less risky environment. Through peatland action and part of the vision for agriculture, we are moving more into this regenerative space for healthy soils on which life depends,” said Mitchell.