About 65 million years ago, the last mass extinction took place, which marked the end of the dinosaurs. Scientists warn that we are now in the early stages of a similar disappearance. But, unlike the others, this sixth mass extinction – or anthropocene extinction – is caused by man, through climate change, habitat destruction, pollution and industrial agriculture.
In mass extinctions, at least three-quarters of all species disappear in about three million years. At our current rate, we are on track for that to happen within a few centuries. In the next few decades alone, at least a million species are at risk of disappearing forever, according to an estimate in a UN report published in 2019.
Trying to predict the outcome of a complete collapse of biodiversity is difficult, as ecosystems are incredibly complex. However, scientists agree that predictions are clear if extinctions continue at this rate. And all effects are linked to each other.
Threat to food security
“The first thing we’re going to see is that our food reserves will start to decrease quite a bit because so much of our food depends on pollination,” said Corey Bradshaw, a professor of global ecology at Flinders University in Australia, who uses mathematical models to show the interaction between humans and ecosystems.
About a third of the world’s food supply depends on pollinators like bees. If they become extinct, farm income could fall, he added. On the other hand, agricultural pests can get stronger as their predators diminish, further impacting our monocultures.
Millions of people also depend on wild animals for food, especially fishing in coastal regions. But fish stocks are under threat and, with them, an important source of nutrition. This lack of food security, also associated with increased droughts and floods, will hit the poorest regions hardest, particularly sub-Saharan Africa and parts of Southeast Asia, according to Bradshaw.
less fertile soils
Soil quality is also expected to deteriorate as certain microorganisms die. Although underrepresented in the data, some researchers believe that microorganisms may disappear faster than other species. Its disappearance could lead to a worsening of soil erosion. This, in turn, would lead to more flooding, as well as lower soil fertility, which would affect plant growth.
Colman O’Criodain of the conservation organization WWF International considers the death of microorganisms particularly dangerous. “In a way, organic matter is like the glue that holds everything together. If you compare it to a Christmas pudding, it has some dry ingredients like bread crumbs, flour and dried fruit, but it’s the eggs and starch that hold it together. together, make the pudding soft and squishy, and give it its shape,” explained O’Criodain.
Hunger for water shortage
Much of the fresh water comes from wetlands, where the water is purified and distributed. An example is the water of the Himalayas, which is fed by wetlands and provides water for around two billion people. If these areas collapse due to the decline of vegetation or the blooming of algae, for example, humanity could lose a lot of water for drinking and agricultural use.
Deforestation is also likely to alter rainfall patterns, as less moisture is evaporated due to the loss of trees. Thus, entire landscapes could dry up, a process currently observed in the Amazon.
The Food and Agriculture Organization of the United Nations (FAO) estimates that around 10 million hectares of forest have been cut annually since 2015. This is equivalent to the area of France and Spain combined. And with the loss of trees and vegetation – key regulators of CO2 in the atmosphere− climate change will get worse and there will be more extreme weather events. Droughts and unhealthy forests also increase the risk of wildfires.
Meanwhile, crop failures and other ecological threats are likely to trigger mass migrations as people try to escape famine and conflict caused by dwindling resources.
Loss of resilience and more pandemics
“What we’ve been doing as humans is simplifying the whole planet, especially the production ecosystems, to the point where they’ve become vulnerable,” said Swedish environmental scientist Carl Folke. “Resilience is often called the science of surprise. If you live in very stable conditions and everything is predictable, you don’t need this protection of biodiversity.
But if you live in more turbulent times, with more unpredictable situations, this kind of portfolio of options is extremely important,” said Folke, founder of the Stockholm Resilience Center for sustainability science research.
The researchers also warn that biodiversity loss could lead to an increased risk of pandemics as wildlife and humans come into closer contact with each other through habitat fragmentation and disruption of natural systems. The most cited example is the 2014 Ebola outbreak in West Africa, which is believed to have been caused by children playing in a hollow tree filled with bats. Although the origin of Covid-19 is still unclear, some studies also link this pathogen to wild bats.
Loss of our heritage
Many conservationists and scientists equate irresponsibly allowing species to go extinct to vandalism. Even if we survive and avoid catastrophic consequences, mass extinction would leave the world severely and irrevocably poorer. The most tragic losses can be those we cannot even see.
“Imagine the consequences of extinction as if it were the burning of an art gallery.” So you’re not even thinking about direct potential value, but you’re thinking about the intangible loss of world heritage,” says Thomas Brooks, Chief Scientist Science and Knowledge Unit at the International Union for Conservation of Nature (IUCN). “Remember that each species is the product of millions of years of evolution. You are looking at the loss of what makes humanity part of the planet. It’s everything that makes us a unit,” Brooks said.
Can species extinction still be reversed?
Despite these catastrophic predictions, there is reason for optimism if humanity does something. “There are seemingly insurmountable difficulties to preserve life on Earth. But on the other hand, there are also many inspiring success stories and examples where people have managed to turn the tide. Act so the curve goes in the right direction, trends are pointing in the right direction,” says Brooks.
Brooks is well acquainted with the challenges. The IUCN compiles the list of global species loss, the so-called Red List, and research has shown that conservation efforts work. A recent study found that losses since 1993 would have been three to four times greater without conservation actions.
Without biodiversity there is no life
Spreading conservation success stories −like the reintroduction of beavers in Europe− seems important in the fight against biodiversity loss. Elizabeth L. Bennett, vice president of the Wildlife Conservation Society (WCS), highlights the importance of large nature reserves for conserving biodiversity. “If they are in the right places, if they are very well planned and managed, they will certainly be very useful.”
As a first step towards this goal, WCS is pushing for the adoption of the “30 by 30” agreement in the Kunming Convention on Biological Diversity (COP15). The agreement calls for 30% of the global land and ocean area to be protected by 2030, roughly double the current level.
Achieving this would be a good start, but any agreement reached at COP15 would only be the beginning of a long journey, warns WWF’s O’Criodain.
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