Climate change, food security and biodiversity are some of the biggest and most pressing issues of our time, and the three elements are very closely linked. A solution in one of these areas could therefore have consequences for the other two. We look at Greenland’s glacial rock flour, which could provide a solution for regenerative agriculture.
Climate change and agriculture are interconnected processes. The role of the agricultural sector in greenhouse gas emissions is known, but not yet well understood. More than a quarter of the world’s greenhouse gas emissions come from agriculture, forestry and land use change. And unless actively addressed, these emissions are likely to increase as our planet’s population and need for food continue to increase. Conversely, climate change can also have significant consequences for agriculture, for example due to drought, floods, heat waves and pests. Climate change can also affect soil fertility, food security and biodiversity, and the availability of irrigation water and agricultural land.
While the potential impact of the agricultural sector on climate change and vice versa is clear, discoveries and innovations around the world are helping to continue to mitigate and minimize the negative impacts of climate change and agriculture on each other.
“If you look at it from a biodiversity perspective, it means you could produce more food in the same area.says Prof. Minik Rosing, professor of geology, University of Copenhagen. “And in some cases I believe we can increase forest areas”.
Case study: Greenland’s glacial rock meal offers a solution for regenerative agriculture
One of those discoveries is the glacial rock flour of Greenland. As the glaciers melt, the rocks, which have been ground into nanoparticles by the weight of the retreating ice sheet, deposit about a billion tons of silt, known as glacial rock dust, per year on the world’s largest island. This is an emerging paradox, where glacial rock flour, a byproduct of melting glaciers due to climate change and global warming, could help mitigate the effects of this phenomenon.
Professor Minik Rosing, professor of geology at the University of Copenhagen, and his team found that the nutrient-rich mud increases agricultural production when applied to farmland, absorbing carbon dioxide from the air. Working with teams in Sao Paulo, Brazil and the University of Ghana, the Copenhagen team has managed to increase maize yields by 30% by using glacial rock flour to offset the impact of rain and heat on poor tropical soils.
The nanosize and mineralogy of the sludge particles allow plants greater access to nutrients, including potassium, magnesium and silicon, compared to normal soil particles. Rosing and his team have documented that the sludge works, and in the aforementioned study in Ghana, they tested it over five growing seasons
That is why his research now focuses on:
- How long does it work?
- What are the most optimal conditions in which the mud can work, what types of crops can benefit most from its use and how much of it should be used.
De Novo Nordisk Foundation has supported this part of the research, and Prof. Rosing welcomes other parties to support other aspects of the research.
Accounting for carbon emissions
The scientists are also developing a method to document the effect of carbon emissions absorption so that a more accurate life cycle assessment can be completed.
Tests have shown that one tonne of glacial rock flour can absorb between 250 and 300 kilograms of CO2 when applied to fields, potentially allowing farmers to sell this as carbon credits.
Key in this process is the small size of the silt particles, because they help speed up a natural process by which rocks absorb CO2. When the sludge dissolves in rainwater and releases its nutrients, it undergoes a chemical reaction that traps carbon dioxide from the atmosphere. The solution is then washed out with drainage water and ultimately deposited on the seabed as carbonate minerals.
As for documenting that the glacial rock is CO2 neutral, the team is expected to have a few years of research ahead of it to be able to document the accounting method for CO2 emissions.
Food and biodiversity
“Success at scale could improve food security and economic imbalances caused in part by the uneven distribution of good quality agricultural land around the world,” says Prof. Rosing.
Geological research shows that the best agricultural land extends across parts of North America and Europe
, mark the edges of the ice caps during the last ice age. As happens today in Greenland, the thick layer of ice grounds the rocks and revitalizes the soil.
“In Northern Europe we think that the reason we are better off than the rest of the world is because we are so much smarter than everyone else. In fact, we simply have better ground under our rubber boots”, said Prof. Rosing.
The volume of a billion tons of new silt deposition per year arises because the land ice with a thickness of 3,000 meters below exerts enormous pressure that reaches the sublayer, and extremely fine particles from the sublayer are washed away with the meltwater. . Because of the
Therefore, the ecosystem in Greenland will not experience any substantial negative impact. By industrializing glacial rock flour, companies would therefore not be tapping into a resource that is important for the Greenland ecosystem.
In the subtropical and tropical areas, the sludge becomes active and the scientists have measured that it does not contain ecologically problematic organisms or concentrations of heavy metals.
“The documentation also indicates a low point environment impact here, but of course there will always be an impact as we strive to change a current situationsays Prof. Rosing
Scaling glacial rock flour
Scaling up the use of the sludge from a pilot phase to actual production requires partners who take on product development and find the best solutions for packaging and transporting the sludge.
“We need partners who can scale up and commercialize productionsays Prof. Rosing.
The Greenland Ministry of Mineral Resources is well equipped to manage the exploitation of this resource. The hope for all parties involved is to achieve greater equality for farmers and economic prosperity in the South. For Greenland, the hope is that by exporting the sludge, the country can strengthen its position as a relevant partner for the rest of the world and project soft power to build bridges between North and South.
The idea of applying fine-grained rock to agricultural land is not new and several studies have shown that by-products from mines or quarries can improve soil quality. And the method has attracted interest because of the added benefit of absorbing CO2.
In the same way, a study led by David Beerlingprofessor at the University of Sheffield, found that spreading crushed basalt on fields not only helps crops grow, but also removes CO2 from the atmosphere and encourages climate-friendly agriculture.