The protection of biodiversity: helping to fight climate change?
Biodiversity plays an essential role in climate regulation, carbon sequestration & our protection against environmental change. Despite all life on Earth working to provide us with a service that is NOT to be overlooked, the human population continues to disrespect the living and non-living environment, putting us at risk of losing it all.
In the interest of cohesion, I thought I would start with a disclaimer. I am a biologist and could talk forever about biodiversity. I won’t do that here, but to get my point across, I will structure this blog much like I would do a lecture. I’ll start by defining biodiversity and addressing why it matters in the context of climate change. Then, I’ll present a few of the reasons for why environmental services are so precious, and leave it to you to decide whether you think biodiversity ought to be considered in future climate-management action plans.
Biodiversity; What is it and why does it matter in discussions about climate change?
Biodiversity is a VERY broad term that encompasses the variety of all life on Earth, starting at a genetic level, and applicable to the variation within species, communities and ecosystems as a whole¹. Let’s think of ecosystems as an interconnected web of organisms — the greater variety of organisms living in the web, the more complex and responsive to change it becomes. If we were to lose one part of the web, there would be enough other ‘branches’ to maintain its structure and, thus, function. Put simply, we need biodiversity, because without it, human life would cease to exist.
We rely on the benefits provided by biodiverse environments to help to make our lives possible and worth living; we dub the things that the environment does to help us ‘Ecosystem Services’. We are massively dependent on these services, more so than most people recognise. If the web in which we live was to become less diverse, there will be fewer ways for it to support us and eventually, it will just give out. Biodiverse environments are more resilient to environmental change¹ and therefore better at preserving our quality of life. It is clear how protecting and even restoring biodiversity can make a significant difference in the fight against climate change; biodiversity is synonymous with ecosystem health, and thus it is of paramount importance in the face of an ever changing climate.
How does this all relate to climate change? Well, it all comes back to 1) carbon and 2) the ecosystem services that environments with considerable sequestration potential offer us in defence of climate-induced change. It’s complicated, but let me try to explain.
1a. An introduction to the carbon cycle
Before we can appreciate how a biodiverse environment can help in the sequestration of carbon and thus the fight against climate change, we must first get acquainted with the carbon cycle.
The Lion King got it right, we really do exist within the Circle of Life, but it’s a little more complex and a lot more important than Elton led us to believe. All life on Earth is part of an endless loop, cycling carbon compounds between the atmosphere and environment in a number of processes.
You, and I, and everyone else on the planet are all carbon-based lifeforms, existing in an atmosphere where carbon is found abundantly in the form of the (infamous) greenhouse gas, carbon dioxide (CO2). When we exhale, we emit CO2 into the air around us — as do most other living organisms — but, far more pressingly, we see vast quantities of CO2 emitted into the atmosphere from industry. The advent of modern technology and our growing thirst for power has massively exacerbated this emission through the industrial burning of fossil fuels. Plants, terrestrial and marine, are our saving grace in this system, taking in CO2 as they photosynthesise. Plant matter is then either consumed by animals or it dies and becomes part of the sediment. If decaying material is left undisturbed, buried under layers of sediment, the carbon within it will be locked out of the cycle and after millions of years, forms fossil fuels (hence the name!). This is the same fuel that we are burning at alarming rates today, releasing carbon that had been sequestered millions of years ago back into our atmosphere. Carbon consumed by animals is fixated into their tissues and remains there until they die; their organic remains are then either consumed by something else, or much like decomposing plant materials, is buried under sediment to lock carbon out of the atmosphere for some time². The cycle is endless, with current measures of increasing atmospheric carbon only accounting for about half of the CO2 emission associated with human activity; the rest has already been taken up by the earth and oceans³.
1b. The link between biodiversity and carbon sequestration
When fighting against climate change, excess greenhouse gas is the enemy, and if we are to have any influence over the long-term climate, the goal is to sequester CO2 in organic matter and bury it in long-term carbon sinks, both marine and terrestrial. Having a vast array of organisms simply existing in an environment can play a vital role in sequestering this excess carbon.
At the most basic level, biodiversity provides a measure of variety within an ecosystem¹, so it would stand to reason that with a greater number of species present, there will be greater opportunities for carbon to be sequestered. For example, a diverse assemblage of trees, plants and other photosynthetic material will absorb increased levels of atmospheric carbon. Environments with greater levels of diversity — in all living things — will help keep carbon out of the atmosphere, with lots of heterotrophic organisms (those who must eat plants or other animals to gain energy) acting as intermediate carbon stores. If organic material is then successfully buried when organisms die, carbon is effectively locked out of the atmosphere, aiding in our fight against climate change (less carbon dioxide = less of a greenhouse effect). If biodiverse environments did not exist, we would see a significant reduction in the rate of sequestration, and processes related to climate change would likely accelerate.
2. Building ecosystem resilience through biodiversity
Schemes to protect biodiversity and mitigate climate change go hand-in-hand. Aside from removing excess CO2 from the atmosphere, the best way to protect against a changing climate is to have healthy ecosystems that are capable of responding to environmental pressures. This is exactly what projects designed to protect biodiversity help achieve by increasing the number of species present in an environment.
As mentioned earlier, biodiverse environments are more resilient to environmental pressure, much like those associated with a changing climate. This is best explained when we consider functional groupings within an environment. A functional group refers to a group of organisms in a community that share the same or similar characteristics; for example, a forest ecosystem may have multiple species that work to clear debris from the floor so that germinating plants can still gain access to sunlight and photosynthesise. Provided that these organisms access resources such as food and shelter at different times of the day, species from the same functional group will co-exist within an environment⁴. Some of you might be thinking “Well, why bother to have multiple organisms perform the same role within an environment?” — you’re not alone in having thought this, and we refer to this phenomena as ‘functional redundancy’. Having an element of redundancy within a biodiverse environment is nature’s way of taking out an insurance policy; should environmental change (such as an increase in temperature) see that one species can no longer survive, then there is another that is ready to take its place and continue working to maintain stability within the ecosystem⁵. Humans are heavily reliant on stable environments so, with that in mind, we can begin to understand how protecting, maintaining and enhancing species diversity can have a positive impact.
The ways in which a biodiverse environment can help support people as they adapt to a changing climate is collectively referred to as ‘Ecosystem-based Adaptation’ (EbA)⁶. In the face of climate change, another way in which a healthy ecosystem can help us is in the protection against natural disasters like tsunamis, rising sea levels and even drought⁶. If an ecosystem was less biodiverse, it would likely lack the integrity to do so. For example, mangrove forests are a great first line of defence against rising sea levels and tsunamis⁷, whilst it’s the general consensus that plant diversity encourages resilience to drought in grassland communities⁸.
Schemes like ‘The Great Green Wall’, an African-led initiative designed to restore over 100 million hectares of degraded land across the Sahel region, and sequester nearly 250 million tonnes of carbon whilst doing so,⁹ will encourage the return of biodiversity, likely boosting environmental resilience AND causing greater amounts of atmospheric carbon to be sequestered. Conversely, a negative change in land use (habitat destruction and the clearing of rainforests, for example), will not only reduce biodiversity in the area but also the ability of the ecosystem to protect us against climate change. What’s more is the destruction of trees, peatlands and other carbon-sinking environments actually results in a re-emission of stored carbon into the atmosphere, directly contributing to global emissions of CO2 and the subsequent warming of our atmosphere. An estimated 23% of human-caused greenhouse gas results from a negative change in land usage, most often associated with agriculture¹⁰.
A summary
Why does this all matter? Because, despite the wavering reputation of tree-planting amongst the public — thanks to companies using the initiative to greenwash their business practices — it still has a huge amount of environmental value, especially when carried out through reputable and credible organisations such as our partner, Eden Reforestation Projects. In addition, we seek to foster relationships with global organisations that work to protect and enhance biodiversity as an indirect means of offsetting and protecting against the ill-effects of carbon emission. We must work to restore and protect biodiversity if we are to see any sort of long-term climatic benefit.
Just like the carbon cycle itself, the link between biodiversity and carbon sequestration is somewhat cyclical in nature, so when we think of biodiversity and the ecosystem service it provides us with, removing CO2 from the atmosphere should be recognised as one of its more notable contributions. We wouldn’t be able to make claims such as those if not for the power of trees and the projects that work to restore their global diversity. A biodiverse environment will sequester more carbon from the atmosphere and its species richness will see that ecosystem functioning continues. Should climate-induced change occur, biodiverse ecosystems will have enough resilience to adapt and persist in the provision of ecosystem services, namely carbon sequestration and the protection against natural disasters. The team at Carbon Fingerprint think this is a pretty worthy case for the inclusion of biodiversity management in any future climate action. What about you?
References
[1]: Chaplin, F. S., Zavaleta, E. S., Eviner, V. T., Naylor, R. L., Vitousek, P. M., Reynolds, H. L., Hooper, D. U., Lavorel, S., Sala, O. E., Hobby, S. E., Mack, M. C. and Diaz, S. (2000) Consequences of changing biodiversity. Nature 405(1). https://www.nature.com/articles/35012241
[2]: Cole, J. J., Hararuk, O. and Solomon, C. T. (2021) ‘Chapter 7 — The Carbon Cycle: With a Brief Introduction to Global Biogeochemistry’ in Weathers, K. C., Strayer, D. L. and Likens, G. E. (eds.) Fundamentals of Ecosystem Science, Second edition. Elsevier Inc. pp131–160. https://doi.org/10.1016/B978-0-12-812762-9.00007-1
[3]: Battin, T. J., Luyssaert, S., Kaplan, L. A., Aufdenkampe, A. K., Richter, A. and Tranvik, L. J. (2009) The boundless carbon cycle. Nature Geoscience 2(1). https://www.nature.com/articles/ngeo618#ref-CR2
[4]: Van der Putten, W. H., de Ruiter, P. C., Bezemer, T. M., harvey, J. A., Wassen, M. and Wolters, V. (2004) Trophic interactions in a changing world. Basic and Applied Ecology 5(6). https://doi.org/10.1016/j.baae.2004.09.003
[5]: Cleland, E. E. (2011) Biodiversity and Ecosystem Stability. Nature Education Knowledge 3(10). https://www.nature.com/scitable/knowledge/library/biodiversity-and-ecosystem- stability-17059965/
[6]: Mant, R., Perry, E., Heath, M., Munroe, R., Väänänen, E., Großheim, C., Kümper-Schlake, L. (2014) Addressing climate change — why biodiversity matters. UNEP-WCMC, Cambridge, UK. https://www.uncclearn.org/wp-content/uploads/library/unep248.pdf
[7]: Sandilyan, S. and Kathiresan, K. (2015) Mangroves as bioshield: An undisputable fact. Ocean & Coastal Management 103(1). https://doi.org/10.1016/j.ocecoaman.2014.11.011
[8]: Isbell, F., Craven, D., Connolly, J. et al. (2015) Biodiversity increases the resistance of ecosystem productivity to climate extremes. Nature 526(1). https://doi.org/10.1038/nature15374
[9]: Great Green Wall. Growing a world wonder. Available at:
https://www.greatgreenwall.org/about-great-green-wall Accessed 18/03/2022
[10]: IPCC, 2021: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S. L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M. I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J. B. R. Matthews, T. K. Maycock, T. Waterfield, O. Yelekçi, R. Yu and B. Zhou (eds.)]. Cambridge University Press. In Press.
