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
How fragile is life on Earth? A rock from an iron ore mine housed in Museum Victoria gives us a clue. It’s a visual reminder of the instability that happens when we remove wildlife. In the long-distant past Earth couldn’t have supported humans. It’s only the rich abundance of animals today that stops wild fluctuations in our climate and planetary life support systems. Life on Mars, for instance, never made it through this stage.
Oxygen giveth and taketh away
Oxygenation of Earth’s atmosphere began about 2.5 billion years ago. Up until about 1.8 billion years ago Earth underwent a period of huge turbulence. So, as Earth grew accustomed to the demands of newly-evolved microorganisms, there were alternating periods dominated by oxygen and iron. Both the aforementioned elements can be used to fuel life. But it would be many more billions of years before oxygen-dependent animals took over the land.
In this early time our seas were dominated by types of primitive bacteria. They were the first wildlife able to start making oxygen.
Oxygen is the main by-product of photosynthesis. It’s a relatively simple equation that uses sunlight to turn carbon dioxide and water into fuel (sugars) and oxygen.
Ironically oxygen happens to be toxic to life forms. So, this is why our lives are so finely balanced with the ecosystems (and animals) around us.
Humans can’t tolerate more than a slight increase or decrease in atmospheric concentration of oxygen. Divers commonly use oxygen-enriched air to limit their nitrogen saturation. But at depths, more than about 30m, will risk central nervous system impacts.
Alternating oxygen and iron states
As cyanobacteria flourished along with purple bacteria, they depleted the ocean’s iron reserves. Until now these had been cleaning the sea of toxic oxygen. How this works is that iron bonds with oxygen to create ‘rust’ and falls to the seafloor.
Once most the iron had been consumed by the bacteria, free oxygen again started to seep into the ocean. This poisoned deep-water iron-eating bacteria throughout the world. The system flipped to a new steady state for the next few million years based around oxygen and silica.
A widely held theory is that following the mass die-off of bacteria, weathering of continental rocks and upwelling of iron from deep ocean volcanos replenished stocks, allowing the micro-organisms to return. Then the whole cycle would repeat over and over, first depositing rust, then a crash in microorganism numbers, followed by a recovery period when silica was deposited, then rust again and so on.
This is why you can see layers of silica and iron in the rock from Museum Victoria. These same patterns are found in rocks all over the world.
We build our society based on the world’s oldest rock formations made by wildlife
Some of the world’s oldest rock formations contain vast deposits of these iron bands, alternating with layers of silicon-based quartz. About 60% of mined iron ore reserves are thought to originate from this primordial process. Hence, almost our entire society since the iron-age has been built on this.
While we’re unlikely to return to a period of such instability in future, we aren’t immune to smaller fluctuations. Because of our size, sophistication and dependence on iron (which is naturally very scarce on an oxygen-rich planet) we need animals to collect it for us. And they need to make it biologically available for our cells.
We also need it to remain scarce, or else it upsets the oxygen part of the system. Which is why iron fertilisation plans are dangerous.
‘Our existence is balanced between having too much or too little of a good thing and, critically, it is wildlife that regulates this balance, and we evolved when things were just right.
Since the Great Oxidation Event 2.4 billion years ago, when iron was rusted into sediments and buried deep underground, biologically available iron (not the iron ore we dig out of the ground) has become so rare, it limits the magnitude of whole food chains. In the Antarctic, even in places where deep water resurfaces fast, photosynthetic microorganisms couldn’t rely solely on iron in the ocean.’
Wildlife in the Balance by Simon Mustoe
If you’d like to read more about why wildlife is essential to keeping our lives iron-rich, buy my book ‘Wildlife in the Balance.‘
