With Europe’s deadly summer heatwave still fresh in memory, scientists from around the world are gathering in Glasgow to focus on the vital role soil plays in maintaining a healthy ecosystem and halting climate change, writes Nan Spowart.
The World Soil Science Congress to be held in Glasgow could be pivotal in the global fight against climate change.
While burning fossil fuels accounts for two-thirds of harmful emissions, land misuse accounts for the other third but receives nothing like the attention it deserves, according to NatureScot’s Clive Mitchell.
He hopes this will change following the Congress, which he describes as a “great coup” 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 will welcome some 1,600 scientists to the city from July 31 to August 5 at the SEC, and Mitchell believes it represents a huge opportunity to bring soil to the fore and make it more central on the journey to grid zero.
“The importance of the soil is very hidden and it’s time to take it out and illuminate it,” he said.
Perhaps because it is under our feet, we forget that soil is vital to human life on earth. “We wouldn’t be here without it,” Mitchell said. “Soil is at the heart of the climate / nature crisis we are currently facing, yet it is a Cinderella subject in relation to her profile in practically everything we do, whether it be conservation, agriculture, forestry, highland management, development of countries and cities and so on “.
Soil is expected to absorb carbon overall, but is currently a net source of emissions globally and in Scotland. This is because humans have disrupted the global carbon cycle through burning fossil fuels (around 70%) and changing land use (around 30%).
Peatlands are drained and degraded, deer suppress peat bogs and woodland restoration, woods are mostly commercial plantations, livestock meadows are mostly fed by synthetic fertilizers, lowlands are mainly monocultivated by heavy machinery with most trees and hedges removed, floodplains are prevented from flooding, urban areas have little green space especially in poorer areas, coastal habitats such as brackish marshes, seagrasses and algae have been reduced and the seabed he is widely disturbed. The landscapes are largely simple.
As a result, carbon that would normally be stored for hundreds or thousands of years in soil and sediments, or for millions of years in fossil fuels, is returned to the atmosphere within a few years. For the climate, these releases are catastrophic.
Terrestrial emissions result from the systematic degradation of ecosystems through the progressive simplification from systems richer in biodiversity to systems less rich in biodiversity, including monocultures and drainage, particularly of moist carbon-rich soils.
Healthy, diverse and effectively functioning soils are essential for a healthy climate-nature system.
Mitchell points out that in order to reach net zero and maintain it, we need to fix the “green and blue” parts of the carbon cycle.
Repairing the “black” part (fossil fuels) is key, but no amount of heat pumps or electric vehicles will repair the green and blue parts, so we need to transform the way we use all the land and sea for agriculture, fishing and forestry.
In Scotland, soils are a huge carbon sink, containing more than 3,000 million tonnes of carbon, of which 53% is held in deep bog soils. This is about 60 times the amount of carbon contained in the country’s trees and plants, which makes soils the main terrestrial store of carbon – and it’s important to keep it there.
In Scotland, around 30-40% of the net zero crossing will go to land.
“Not burning fossil fuels is vital, 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 acknowledge if we help to enter the lower end of the Paris target range of 1.5-2 ° C. This is where the Scottish government’s ambition rightly lies, but it will require huge transformations in the way we use the land so that it becomes a net carbon sink. “
One way or another, the use of land and sea will change. If the world chooses a world + 2oC – and it is a choice – the changes are largely beyond human control, increasingly driven by the impacts of a changing and chaotic climate, which imposes increasing costs of loss and damage on people and the planet. .
However, in a world of 1.5 ° C, the changes are more under human control. This “no regrets” path is by far the least expensive for people and the planet. Following this path requires the re-humidification and restoration of the peat bogs, making commercial and conservation forests more diverse and resilient.
Agroforestry would be the norm, with more hedges and trees from farmland and intercropping to control pests. Farms would mix crops and graze cattle extensively, river banks would be forested, and floodplains would allow flooding.
There would be more green space in cities to manage surface waters, enhance local nature and sequester carbon. There would also be more extensive and diversified marine habitats and less perturbation of the seabed to ensure both productive fishing and greater resilience of marine biodiversity undergoing a long 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 the potential for transformation exists, such as the Scottish Government’s Peatland Action program and many examples of farms using regenerative practices, i.e. those that improve soil health, increase biodiversity and sequester carbon through l ” use of practices such as cover crops, crop rotations, minimum tillage, organic fertilizers, agroforestry and crop-farming integration.
However, it must also be recognized that not only the use of land and sea must contribute to and maintain net zero, but it must be resilient to inevitable changes.
These consequences include increased frequency and intensity of floods, fires, droughts, pests, diseases and pandemics. A changing climate has a more serious impact on nature and associated services the simpler and more degraded it is.
Soil health and a more diverse nature not only create resilience to these events, but make them less likely by correcting disruptions in carbon, nitrogen, and other key cycles.
“The agriculture, forestry and species diversity we use to grow food are key to building resilience to the impacts of climate change, which obviously include pathogens and diseases in natural systems, crop systems and forest systems,” as well as in human systems – as we’ve seen recently with the pandemic, ”Mitchell said.
“Our current food systems produce foods rich in sugar, fat and energy dense that are not very good for the health of the population and are based on production systems that are degrading soil and nature and contributing to climate change.
“We have to change both what and
how much we eat so that our diets contribute both to the population and to the health of the planet ”.
Mitchell argues that there is room for meat in a net zero world, but it should come from a production system more focused on integrating livestock and arable systems, with more emphasis on organic fertilizers while at the same time adapting the breed to suit earth capacity. In a Scottish context this could mean using efficient but smaller breeds.
The environmental cost of manufacturing should also be reflected in the price, according to Mitchell.
“There is really important work to be done in combining sustainable production with sustainable consumption,” he said.
“That relationship between the price of goods and the cost to society and the planet is vital.
“To avoid spill problems, you should make sure that there was a carbon tax applied at the borders to carbon-intensive goods so that it covers both things produced within the country and imports.
“This reduces the risk of losses so that you don’t have goods produced at an environmental cost that compete 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 of the University of Aberdeen, lead author of the Intergovernmental Panel on Climate Change for their soil and land use work,” he said. “And Scotland is at the forefront of efforts to restore peatlands.
“The Scottish government has invested £ 250 million over ten years and it is widely recognized that this is a good start, although we will likely need to double it 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 where we can secure private money in a much less risky environment. Through peat bog action and part of the vision for agriculture, we are moving more into that regenerative space for healthy soils that life depends on, ”Mitchell said.