The link between carbon sequestration and avoiding global catastrophe
Like me, you’ve probably seen a lot in the news and on social media about how the fallout from climate change is coming for us all, and that if things stay as they are, we’re most likely not going to survive.
“We” as in us regular folk… I’ve no doubt that the ultra-rich and super-powerful (not typically the best examples of humanity) will be fine. As permafrost melts and we drown in floods caused by rising sea levels, or choke on the carbon that’s being released by that same melted permafrost, or burn alive in wildfires that are set to storm with increased regularity through the ill-prepared tinderboxes that we currently call our cities and forests, they’ll fly free and clear of the death and carnage to their own private islands on their own private jets. The same private jets that have played a substantial role in us being where we are right now.
The +40°c heatwave in Summer 2022 felt, to me, like a glimpse into a truly terrifying future. I’m fair-skinned and I crisp up like burnt bacon unless I’m smothered in factor 50. Most of my family members are the same – while other people were talking about how lovely the weather was, we were strategically planning a swift Nordic escape. I literally did not leave the house on those two days when the temperature reached its peak. But aside from a bit of general, sweaty misery; I fared okay. I consumed more than my bodyweight in bagged ice from Aldi, and with no work scheduled and no strict deadlines to keep, I was free to strip down to next to nothing (ok, nothing) and perch in front of a struggling fan while streams of unhelpfully hot air flowed across my body. Other people weren’t so fortunate.
One thing I think we can all agree on is that right now, the earth is off-balance. Mother nature is furious, or at the very least a bit pissed off. And who can blame her? Based on the latest IPCC report, each of the last four decades have been successively warmer than any decade that preceded it since 1850. It also states that the burning of fossil fuels is the main driving force of climate crisis, including the global retreat of glaciers and the decrease in Arctic Sea ice area. Human influence is warming the climate at a rate that is unprecedented, at least in the last 2000 years. Carbon emissions aren’t our only adversary, but they’re certainly one of the biggest. It is vitally important that we discover, utilise, and then streamline the most effective methods of carbon removal at our disposal.
Thankfully, global society already seems to be a few steps ahead on this.
What is carbon sequestration?
Approximately 45% of human-produced carbon (CO2) emissions remain in the atmosphere, and carbon sequestration is the practice of capturing and removing that carbon and storing it in a safer format/environment. It’s scientifically recognised as the key method for limiting the levels of carbon in the atmosphere and reducing its contribution towards global warming.
It’s important to give credit where it’s due, and I do recognise that many forward-facing changes are being implemented the world over with the aim of reducing carbon emissions - changes to the ways we construct, consume, travel, and generate power. But this isn’t enough on its own. We’re too far gone for the “We’ll be good from now on…” mentality, and rather than just slowing down to a gradual stop, we need to do an emergency brake, a full 180°, and then start pushing ourselves hard, back the way we’ve come and all as one.
If avoiding climate catastrophe is our ‘why’, then carbon sequestration is our ‘how’.
Here are my three favourite methods of carbon sequestration
1. Afforestation and reforestation
Tree-planting is probably the most well-known of climate change ‘solutions’, and afforestation and reforestation are both practices aimed at increasing the number of trees in an area, though they differ in their specific approaches. Afforestation involves the establishment of new forests in areas that have not previously been forested. Reforestation involves the replanting of trees in areas that were previously forested but have since lost significant tree cover due to human activities like logging, wildfires, or land clearance for agriculture or development. Planting trees and restoring forests not only sequesters carbon in the growth of the trees themselves but also the surrounding soil through leaf litter and root systems, contributing to increased organic matter in forest soils.
On a smaller, more domestic scale, we can ‘reforest’ our gardens by planting small, deciduous trees and herbaceous perennials, and then allowing the leaf litter to rest where it falls instead of collecting it up. Rather than an autumnal tidy-up, allow the dead top growth of plants to stay in place throughout the winter and then chop-and-drop it where it stands come spring. Not only will this build up the layers of soil, but it creates a welcoming habitat for wildlife to thrive.
Image depicting National Trust afforestation initiative, The Guardian
2. Soil carbon sequestration
Soil carbon sequestration refers to the process of capturing atmospheric carbon dioxide (CO2) and storing it in the soil in the form of organic carbon. Soil carbon sequestration has multiple benefits beyond climate change mitigation. It improves soil structure, fertility, and water retention, which enhances both domestic and agricultural productivity and increases resilience to droughts and floods. Additionally, it promotes biodiversity by creating a favourable environment for everything from soil organisms to foraging birds and mammals.
We can all increase the levels of carbon in our soil by implementing farming/gardening practices like cover cropping, crop rotation, and the regular application of beneficial fungi and topdressings like compost, manure, and other organic mulches. In particular, the ‘no-dig’ method of land management is excellent as it encourages us to recognise that the soil beneath our feet is not inert and lifeless. You’ve probably heard the saying “There are more living things in one teaspoon of soil than there are people on the planet”, and while it might seem hard to believe, it really is true! One gram of soil can contain several billion bacteria from thousands of different species, and without this biological diversity, there would be no terrestrial life on Earth. By reserving our spades for planting and transplanting alone and doing our best to build the soil upwards instead of working our way down, we can ensure that the inconceivably vast network of fungal and microscopic activity beneath our feet is left untouched and intact.
Image depicting soil carbon sequestration, Field of Mars Environmental Education Centre
3. Biochar
Biochar is a type of charcoal produced via a process called pyrolysis, where biomass is heated in the absence of oxygen. Adding biochar to soils can boost carbon sequestration by providing a stable form of carbon that resists decomposition. It can store carbon for hundreds or even thousands of years, enhancing soil fertility and reducing CO2 levels in the atmosphere.
Besides its carbon storage abilities, biochar offers several other benefits to soil and the environment. It’s an incredibly porous substance and acts like a sponge when added to soil, improving both water retention and nutrient availability for plants. To work as a soil conditioner, it must first be inoculated with an organic amendment, such as compost, manure, or a liquid fertiliser. All the nutrients and billions of microscopic lifeforms transfer across to the biochar, making even a small amount highly potent. By promoting microbial activity, it aids in breaking down organic matter and cycling nutrients, thereby fostering a more resilient and fertile soil environment.
I don’t have biochar integrated into my home composting system yet, but I’m eager to explore its potential!
Image depicting the porosity of biochar, Dr. Simon Shackley (The University of Edinburgh)
As you’ve no doubt noticed; the ground-level, hands-in-the-earth, nature-based approach is kind of my thing, but there are more methods at our disposal than just my three favourites listed above. Here’s an overview of some more:
Carbon mineralisation, also known as mineral carbonation or carbon sequestration, is a process where carbon dioxide (CO2) is chemically reacted with minerals to form stable carbonate compounds. This process occurs naturally over long periods, but scientists have been exploring ways to accelerate it as a potential method for carbon capture and storage to mitigate climate change.
Grassland and Wetland Restoration involves managing grasslands and wetlands in a way that encourages the accumulation of organic material in the soil. These ecosystems have the potential to store significant amounts of carbon in their soils.
Bioenergy with Carbon Capture and Storage (BECCS) involves growing biomass (such as trees or energy crops), which captures CO2 as it grows through photosynthesis. The biomass is then burned for energy production while capturing the emitted CO2 and storing it underground, preventing it from entering the atmosphere. BECCS aims to produce energy while simultaneously removing CO2, thus achieving negative emissions.
Biomass Storage involves preserving harvested biomass, such as timber or agricultural residues, in a way that prevents the released CO2 that would result from decomposition. By using biomass for longer-term products or storing it in a way that prevents decay, the carbon within the biomass remains sequestered.
Direct air capture (DAC) is a technology designed to remove carbon dioxide directly from the atmosphere. It involves the use of specialised machines or systems that capture CO2 molecules from the air. This captured CO2 can then be stored underground or utilised in various industrial processes or technologies.
There are also a variety of methods for carbon removal utilising the ocean. These include coastal wetland restoration, seaweed cultivation, artificial upwelling and downwelling, nutrient fertilisation, alkalinity enhancement, and electrochemical CO2 removal.
I live about as far from the ocean as possible in the UK (and I have wobbly sea legs) so I think I’ll leave the explanations of those methods to someone else! For anything soil-related though, you can count on us.