Some 66 million years ago, a meteor crashed into the coast of Mexico’s Yucatan Peninsula, marking the end of the age of dinosaurs. It was a mass extinction event and it was devastating. It’s estimated that some 75% of all marine creatures went extinct — and it’s not even the worst one. There have been five notable mass extinctions that hit the Earth, each marking the end of a geological age.
At least that’s what you’d think at first glance. Actually, there’s a sixth mass extinction, one that’s happening right now — and one we, humans, are causing.
A mass extinction is a short period of geological time in which a high percentage of biodiversity, or distinct species (bacteria, fungi, plants, mammals, birds, reptiles, amphibians, fish or invertebrates) dies out. It’s important to note that, in geological time, a “short” period can actually span thousands or even millions of years.
The first five mass extinction events were the Ordovician-Silurian, the Late Devonian, the Permian-Triassic, Triassic-Jurassic and the Cretaceous-Paleogene. The Permian-Triassic extinction was the deadliest as it caused the loss of about 90% of the species. The Cretaceous-Paleogene extinction, the most recent one, destroyed the dinosaurs.
The sixth mass extinction is ongoing. Usually called the Holocene extinction by scientists, referring to the geological epoch that started around 10,000 years ago, or the Anthropocene extinction, referring to the epoch when humans started impacting the planet’s ecosystem and climate. We started changing the environment, destroying habitats, even changing the climate. All this is triggering an extinction across the globe.
The species extinction rate is estimated to be between 1,000 and 10,000 times higher than natural extinction rates — the rate of species extinction that would happen if humans weren’t around.
What’s causing the sixth mass extinction?
Unlike previous extinction events that were caused by natural phenomena, the sixth mass extinction is driven by human activity. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), a group of leading scientists on biodiversity, found that there are five main drivers behind the crisis of the natural world.
The biggest driver of destruction is how we use the land and the sea. This includes the conversion of land cover such as forests and other natural habitats for agricultural and urban use. Around 420 million hectares of forests have been lost since 1990, the equivalent of 51,000 football fields every day. Agricultural expansion is the main driver behind deforestation, with animal farming being a particular driver of forest degradation and forest biodiversity loss.
The natural world is also affected by the climate crisis. Species and ecosystems around the world, especially the most vulnerable ones, are affected by the rise of greenhouse gas emissions. Mankind’s emissions of greenhouse gases are warming up the atmosphere and subsequently, everything on Earth. It’s not uniform warming, either: global warming is triggering more intense (and often) extreme weather, disrupting natural cycles and fueling things like heat waves, drought, and coastal erosion.
The emission of greenhouse gases, particularly carbon dioxide, is also driving ocean acidification. Basically, there’s so much CO2 in the atmosphere that a part of it dissolves into the ocean, changing its pH — a process which many marine creatures can’t survive. All animals in the seas are affected by this, but animals like corals and oysters are particularly at risk.
Pollution is also a major driver of biodiversity and ecosystem change, especially affecting freshwater and marine habitats. Plant and insect populations are dropping due to the use of highly dangerous insecticides. Marine plastic pollution has increased tenfold since 1980 and air and soil pollution are also on the rise around the world.
The direct exploitation of natural resources, including hunting, fishing, logging and the extraction of soils and water are also negatively affecting ecosystems. A recent report found the unsustainable use of plants and animals threatens the survival of one million species and also the lives of those who rely on them for food and income.
Invasive alien species (IAS) also have devastating impacts on plants and animals, causing the decline or extinction of native species and negatively affecting ecosystems. The global economy has facilitated the introduction of IAS over long distances and beyond natural boundaries, and their effects have increased due to climate change.
All of these factors interact with one another and accelerate one another, harming wildlife through a thousand different cuts.
Why should we care about this?
You could argue that we are morally bound to be responsible stewards of the planet. We are causing this problem, and it should be our responsibility to solve it. But even if you shrug at that argument and don’t care at all about other species, you should probably still care about preserving biodiversity.
Species don’t exist in isolation, they are all interconnected with each other; which means we are all interconnected with each other, even though we may not realize it. A single species interacts with many others in specific ways that produce benefits to all of us and when one species goes extinct or its population drops significantly, other species and ecosystems are also affected. Pollinators are one good example of this: many ecosystems rely on them and if pollinators collapse, the whole ecosystem can collapse. It’s estimated that pollinators provide environmental services of over $200 billion a year, though that’s likely an underestimate. In general, extinction tends to be ‘contagious’ — if the ecosystem loses one species, it can be disbalanced and lose more and more. Why ecosystems can usually recover with low extinction rates, they can’t recover when going through a mass extinction.
The current rate of extinction is high enough to threaten ecological functions that are essential for human life. Agriculture is one such aspect, but virtually all aspects of human life, from the air we breathe to the food we eat depends on ecosystems.
If we don’t change course right now, we’ll continue to lose life-sustaining biodiversity at an alarming rate and at some point, the damage becomes accelerated and irreversible. The good news is that there’s still time to take action and avoid ecosystems crossing critical tipping points, but things are not looking on track right now.
How can we stop the sixth mass extinction?
Urgent action is needed to curb human impacts on biodiversity. This is where the new biodiversity agreement currently being negotiated enters. Governments are trying to agree on a global treaty to halt and reverse biodiversity loss by 2030. However, there are still many differences between governments on how that deal will take shape.
Every ten years, the UN negotiates something called a Global Biodiversity Framework, which sets goals for member nations over the next decade. The previous one, called the Aichi targets, included goals such as reducing deforestation by at least 50% and curbing pollution so that it no longer harmed ecosystems. However, countries failed on almost every target.
Now, the draft text of the new agreement includes four long-term biodiversity goals for 2050 and 23 action targets to be completed by 2030. The latter includes five targets focused on making sure humans use nature sustainably and eight to protect biodiversity. One of the main ones would be a commitment to protect 30% of land and sea by 2030.
Countries and campaigners believe this time things could be different, as the new agreement commits countries to more specific action and includes much more detailed measurement and accountability. But, to pull it off, developed countries will have to commit much more funding. The nature funding gap (the difference between the money needed to ensure conservation and the money that is actually put to this use) is now as high as US$824 billion per year. Simply put, like with climate, we’re not doing nearly enough — and the window of opportunity is closing soon.