Wildlife, biodiversity and climate
A habitable climate depends on wildlife and biodiversity, because:
- Climate is a consequence of biodiversity and biodiversity is everything that ecosystems represent to life on Earth;
- A stable climate and therefore, a habitable Earth, depends on stabilising ecosystems; and
- Animals are the only mechanism that can do that.
As wildlife declines, we are breaking down biodiversity structure and losing energy (in the form of carbon) out of food chains and into the atmosphere and ocean. This way, climate and our food security are inextricably linked. We’re not only stripping soils of the material needed to feed us, we’re also introducing chaotic free energy into our atmosphere and causing huge fluctuations in the weather. The latter makes it harder for us to know when, where and how to feed ourselves.
Climate change: fossil fuels v. wildlife
Climate change has always been the symptom of biodiversity loss … that’s to say, the breakdown of the complex connectivity between lifeforms that allows Earth to flex in response to changing conditions.
Only recently have we created artificial climate change by mining carbon buried deep underground by animals millions of years ago. The animals that did that are no longer around and today’s animals, that would be busy moderating modern-day carbon, have populations that are heavily depleted.
We cannot engineer our way out of this crisis. We can only rebuild ecosystems rich in a diversity of animal life.
Latest posts about why the oceans are important
I’ve been asked, is the ocean more important than land? This really depends on your context (as I discussed in this previous blog “Is the Ocean or Land more Important?“). Overall though, animals control the health of the sea and we can’t live without the land and ocean operating together. And when it comes to fish like tuna, we find the ocean can’t exist without them, at least not in a way that supports human or other animal life. This means that the key to restoring tuna populations is not to catch fewer but to restore all the other wildlife in the ocean.
Is the ocean different to land?
On first appearances, it would seem marine vertebrates function more significantly in the ocean than their terrestrial counterparts do, on land. This has led many scientists working on land or ocean, to think the two systems are different. I don’t believe this.
I think this common opinion arises from an observation bias, based on two things:
First, compared to land, oceans still have intact megafauna like whales and dolphins.
At least up until very recently, humans weren’t exploiting the sea. Most land-based megafauna went extinct in the Pleistocene, 30,000 or more years ago. On land, we’re not seeing anything near to intact ecosystems. It’s like comparing apples and oranges … or more accurately, comparing an apple on a tree, to a spent apple core on the ground.
Second, marine animals are more visible than land animals.
On land “we can’t see the animals for the trees”. We underestimate the importance of land animals in ecosystem processes because they are concealed by vegetation and many wild animal populations have already declined massively.
In the ocean, plants are substituted for invisible micro-fauna like marine algae and cyanobacteria. Incredibly, bacteria make up 78% of the world’s total carbon-based biomass [1] and are the most abundant organisms in the ocean. Yet we can see through them, so fish and other marine animals appear more visible and significant to us.
Animals control the health of the sea
There is an advantage to understanding how the ocean works. It literally gives us a clearer insight into how animals control the health of the sea. Wildlife is essential to the integrity of any ecosystems, land or sea. In the ocean, we are observing something closer to how it should be working and without too much of our own observation bias.
The ocean is deep and has many different layers. However, things are significant for humans, only as a result of the great oxygenation event, which happened about two billion years ago. This was when cyanobacteria evolved a silica-based sunscreen, protecting their fragile DNA from the Sun’s ultraviolet radiation. This set into motion the oxygenation of our atmosphere and the whole course of evolution that led to land plants, land animals and ultimately, us.
Restoring native animal populations is essential to our prosperity and that this means restoring entire food chains that support those species of greatest importance to us. For example, restoring global tuna populations is clearly essential for food and climate security but can’t be done, without a supporting cast of other wildlife.
If we want to protect our future, we have to be thinking about rebuilding populations of fish, seabirds, marine mammals and so on. Because, from a human survival perspective, the domain we live in, is the one shared with animals most like us, the ones that are also oxygen-breathing and connect us to the nutrient and climate cycles that provide mutual food security.
The magnitude of animal impact on the sea
Just in the last few years, there has been a flurry of studies that describe the magnitude of effect this animal impact on Earth’s biodiversity. One published recently in the Journal of Limnology and Oceanography [2] quantifies the animal impact of marine fish, finding that they are responsible for 16% of the carbon cycle. Marine vertebrates as a whole, are responsible for up to a third of all physical ocean mixing [3].
It’s not just the magnitude of the impact of animals to control the health of the sea though, it’s where and when it happens, that matters most of all. Animals have been sampling the environment for literally millions of years. They are a ‘remote sensing’ resource bigger and more accurate than anything scientists can replicate. This is why they are our greatest asset when it comes to nature-based solutions.
Animals can pinpoint exactly where and when it’s most effective to apply their trade. Based on their sampling efforts, animals have learned to transfer, amplify and concentrate nutrients in precisely the right places, to minimise ecosystem collapse.
This way, animals work to their own survival advantage, while maximising the success of other resource dependent animals, that are doing the same. This is the very definition of biodiversity. It’s what animals do, not what ecosystems are, that matters.
Our fisheries resources depend on the health of the sea
Some of our greatest resources depend on animals controlling the health of the sea. The Coral Triangle, for instance, provides direct food security for 250 million people. However, the health of these coastal and marine ecosystems are also essential for global climate and food. Yet, 96% of fishers working in small-scale fisheries, overwhelmingly in developing countries, are some of the least-supported by fisheries grants and among the poorest people on Earth [4]. All our futures are entwined with protecting the living, animal-dominated ecosystems that sustain our most powerful global life support systems.
It seems to me, that it’s more apparent in the oceans, than anywhere else, that restoring native animal populations is essential to our prosperity and that this means restoring entire food chains that support those species of greatest importance to us. For example, restoring global tuna populations is clearly essential for food and climate security but can’t be done, without a supporting cast of other wildlife, as ecosystem stability cannot be upheld by any species out of proportion with the rest of the food chain.
The good news is, the by-product of conservation is the greater capacity to absorb carbon, more stable climate and more predictable and ecologically-sustainable fisheries, plus food security for millions of people. Not a bad result to be achieved from just rebuilding wildlife populations, is it?
Now what we need is recognition that restoring wild animal populations everywhere, and that this learning from the ocean, is directly transferrable to land-based ecosystems as well.
- Bar-On, Y., R. Phillips, and R. Milo, The biomass distribution on Earth. Proceedings of the National Academy of Sciences, 2018. 115: p. 201711842.
- Saba, G.K., Burd, A.B., Dunne, J.P., Hernández‐León, S., Martin, A.H., Rose, K.A., Salisbury, J., Steinberg, D.K., Trueman, C.N., Wilson, R.W. and Wilson, S.E. (2021), Toward a better understanding of fish‐based contribution to ocean carbon flux. Limnol Oceanogr. https://doi.org/10.1002/lno.11709
- Dewar, W., et al., Does the marine biosphere mix the ocean? Journal of Marine Research, 2006. 64.
- Development, I.I.f.E.a. Action for an ocean for all: Rethinking the blue economy to be inclusive, sustainable, fair and for everyone 2019 [last accessed, 13 April 2020].
