🐾 Biodiversity and Climate
A health check on biodiversity, ecosystem services it provides, and the interplay between climate change and biodiversity.
Biodiversity, the life support system of our planet, is all around us. It’s the birds that sing in the morning, the trees and plants that make up our forests, and the microbes in our guts. Biodiversity is also the genetic variability that makes each fish, plant, and human unique. Ecosystem diversity, from the savannas of Africa to the tropical jungles of the Amazon, is also biodiversity.
Earth is teeming with life. But if we keep overexploiting, destroying, and polluting our shared environment, we risk losing this amazing diversity. In this week’s edition of Seagnal, a newsletter at the intersection of tech and sustainability, we’ll dive into the services nature provides (free of charge !), the current state of biodiversity and the interplay between biodiversity and climate change.
Ecosystem services
Ecologists, scientists who study the relationships of organisms and their environment, have coined the term ecosystem services to describe the gifts that biodiversity provides to humanity. These benefits are often categorised into provision services (eg. free resources like food and wood), regulating services (eg. climate regulation), and supporting services (eg. soils and habitats).
Regulating services are often overlooked, and taken for granted. But remember, it’s biodiversity that pumped out all the CO2 from prehistoric atmospheres with revolutionary photosynthesis, transforming Earth into a habitable planet. It’s biodiversity turned soils fertile, and rivers into breeding grounds.
“Biodiversity […] regulates climate, natural hazards and extreme events, air quality, the quantity and quality of fresh water, pollination and the dispersal of seeds, pests and diseases, soils, ocean acidification, and the creation and maintenance of habitats.” - Sir Robert Watson, WWF’s Living planet report 2022
Despite trying to emulate the regulating services nature provides, for example using fans to remove CO2 from the air or pollinating by hand, we so far struggle to make these imitations a closed loop. For example, we might have mastered water sanitation, but we still depend on non-renewable energy inputs and chemical treatments that generate waste and emissions in the process of purifying water.
We are reliant on nature’s regulating services to provide a liveable planet. So how do we protect and monitor the health of biodiversity?
The 6th mass extinction
Ecologists assess the state of biodiversity using observation measures such as species abundance and extinction rates (amongst many others).
Extinction rates, which measure the frequency at which species vanish from the ecosystem, are up to 1000 times higher than the natural background rate. This alarmingly high rate points to accelerated biodiversity loss, often driven by human activities.
“[…] current extinction rates are 1,000 times higher than natural background rates of extinction and future rates are likely to be 10,000 times higher”. Estimating the normal background rate of species extinction - Journal of Conservation Biology
Abundance, which refers to the number of individuals of a particular species within a given ecosystem, is another critical metric. According to the World Wildlife Fund (WWF), there has been a 69% decrease in relative abundance of monitored wildlife populations between 1970 and 2018. Long gone are the days when your windshield would be covered in bugs after a drive through the countryside.
Together, these point-in-time measures, are leading researchers to express concerns that humans are causing a sixth mass extinction event (defined by the loss of at least 75% of species). While everything is still under control (ie. no actual mass extinction yet), we are clearly heading in the wrong direction.
Numbers of terrestrial and aquatic genera at times of extinction events. Wikipedia
While causes of previous extinction events are still debated, we know that current major threats to biodiversity are habitat destruction, over-exploitation and pollution. For example, to produce palm oil, an irresponsible capitalist might clear primary forests (habitat destruction), deplete soil nutrients and water resources (over-exploitation), and use pesticides contaminating nearby rivers (pollution).
Climate Change x Biodiversity
We’ve seen both the vital importance of biodiversity’s regulating services and current threats to biodiversity, which we can act on today. Before concluding, let’s dig a bit deeper into the interplay between climate change and biodiversity’s regulating services.
A word of caution: unlike other physical effects (eg. thermal radiation) living interactions are hard to model. While we are not able to predict well the role of biodiversity in the future (eg. at 1.5 degrees above pre-industrial levels warming), we are better at modeling the current carbon cycle.
Left: carbon cycle accounting - numbers vary but good overview of stocks and flows of CO2 - source. Right: Climate feedback - large error bars for land and ocean C02 response related to modeling difficulty discussed - source.
From these graphs we can see that :
Nature’s carbon flows are much bigger than human CO2 emissions.
About 40% of human-induced CO2 emissions are absorbed by nature.
In climate feedback, carbon response goes both ways with a lot of uncertainty.
Having nature on our side is a big help! However, it shouldn’t be lost that this comes with side effects such as having a lot of carbon stock in the form of living organisms.
Potential positive climate feedback loops (in other words: more climate change -> less biodiversity -> more climate change) could hurt both nature’s CO2 stocks and flows (eg. forest fires). The opposite is also true: more CO2 could mean even more life (eg. phytoplanktons) in stable ecosystems.
If we lose ecosystem stability or shift into new hierarchy orders less inclined to store CO2, we could be in for quite a ride. For example, over-fishing of apex predator fishes (like tuna), could reduce phytoplankton population and result in less ocean CO2 uptake. Because it’s hard to model the repercussions of our actions, we are kind of driving blind.
Conclusion
We are still very reliant on nature’s services to provide us with a diverse, rich and liveable planet. Yet, every day we are destroying more of this precious gift, razing habitats, over-exploiting, and polluting, just to support our extravagant lifestyles.
The good news is that we are far from positive biodiversity climate feedback loops, meaning we can act on biodiversity protection today. We must therefore prioritize the protection and monitoring of our planet's life support system. Beyond the moral implications of detroying life, preserving biodiversity will also:
Mitigate climate repercussions by offsetting substantial amounts (~40%) of our emissions.
Stabilise ecosystems once we stop emitting CO2.
By understanding and preserving biodiversity, we ensure a sustainable future for us all. Our everyday actions impact biodiversity! You can help by:
Having a vegetarian diet (grazing land is responsible for 41% of tropical deforestation).
Minimising palm oil products (18% of tropical deforestation is for palm oil and soy plantations; much of soy itself is used for cattle).
Switching to organic, local, regenerative agricultural products.
🔗 - Check these out
This week’s links are intended to showcase the beauty of Earth’s biodiversity:
My Octopus Teacher on Netflix - Dive into the South African kelp forest with filmmaker Craig Foster forging a relationship with an octopus.
Empire of Ants by Bernard Werber - A fascinating fiction story narrated through the eyes of an ant.
BBC’s Planet Earth show - Explore wildlife across mountains, rivers and forests beautifully narrated by David Attenborough
From San Fransisco 🇺🇸,
Jean
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