It may surprise you that biodiversity is one of the planetary boundaries. But when one sits down and reflects a bit it becomes very obvious that biodiversity must be one of our planetary boundaries.
Think of it, without the living species everything from vegetation, trees to animals and small insects, pollinators, we would have no biomass, there would be no carbon sequestration, there would be no rainfall because a large portion of our fluxes of water originate from the canopy, from vegetation transpiring and evaporating water back to the atmosphere. It regulates the flows of fresh water, regulates the flows of carbon, nitrogen and phosphorus.
The living biosphere is a fundamental component in regulating the stability of the entire Earth system. And this relates to two components. One is the genetic diversity; the treasure of genetic code, which forms the adaptive capacity of the entire Earth system. But it’s also the diversity of functions that we know today that in order to develop, for example, food for a world population of 7 billion people we need the functions and landscapes for pollination, the function of microorganisms in the soil to develop organic matter which in turn delivers nutrients for plants, without which we would have no food.
So we need to explore the functional diversity and the genetic diversity in the rich treasure of living species on Earth. And this forms part of a core fundamental part of a living planet. The drama is that we’re really mismanaging biodiversity in the world. In fact we are today, based on the observations we have, in the sixth mass extinction of species in the world, the first extinction to be caused by another species, and one of these six, for example, being when we lost the dinosaurs 65 million years back on Earth.
So these are big, dramatic changes, illustrated here for example when it comes to how we’re dealing with global fisheries. Just over the past sixty years from the 1950s and the onset of the great acceleration when we started the exponential rise in pressures on planet Earth, you see here the extraordinary social-ecological journey of not only increased landings of fish, but also that fish efforts are changing dramatically from small scale fisheries to large scale industrial fisheries where we are basically vacuum cleaning large tracts of oceans, not only in shallow waters but also in deep ocean regions.
We have the classic examples of collapse of fisheries; like the cod fisheries off the shores of Newfoundland, where we’re learning unfortunately that once we cross a tipping point with regards to loss of fisheries we can actually lock the system in a situation where the fish does not even come back.
So these are big, dramatic changes that we need to incorporate in our understanding of the resilience of the Earth system. We also have interactions between species.
This is an example of how delicate the system works in terms of relationships between seabirds and fisheries. A large synthesis across essentially all marine systems across the world shows that when we overfish and lose more than 30% of fish stocks that has an abrupt impact on seabird populations which go through, and cross a threshold leading to abrupt changes in populations. So loss of one species in this case over-fishing, has a propelling effect on seabird populations which risk collapse, in fact, in many parts of the world.
So again the risk of not connecting diversity in species and thereby not understanding that this can lead to propelling effects across the world. A fundamental, very essential part of our own future is of course the ability to produce food. And there’s another example of how a function in ecosystems simply provides us with a free service, namely pollinating insects.
And here’s one example of a global concern among farmers, scientists, citizens in general, that we’re losing pollinating bees at a very rapid pace, to the extent in fact that some agricultural regions are collapsing. We have human beings have to step in and function as human insects to pollinate apple orchards in China. We have examples of collapse of pollination in some parts of the UK, United Kingdom, because of overuse of pesticides which led scientists to pop over to neighboring countries in Scandinavia and try to borrow bumble bees to be used as pollinators in their own agricultural systems.
So again, understanding that biodiversity – without biodiversity we cannot have modern agricultural systems, and therefore we get locked in an undesired state in terms of delivering human well-being.
So in summary, what occurs is the recognition that biodiversity is fundamental for the regulation of the Earth system, it’s fundamental for human well-being. We tried based on this evidence to identify what could be a good control variable, an indicator for a planetary boundary on biodiversity?
We took as a first starting point an indicator that maps out the rate of extinction, how many species we’re losing, over time. And this indicator called the extinction rate per million species per year, which is a good indicator of the pace of loss of biodiversity.
The natural background rate of loss is roughly one species per million species per year, that’s the normal background rate. We estimate as a first guess that a boundary lies somewhere between ten and hundred lost species per million species each year. So the boundary was placed at ten species lost per million species per year. Now today we’re losing species at roughly ten to hundred times faster that rate. That’s why we can today say with quite a high degree of confidence that we’ve actually transgressed and are in a danger zone on biodiversity.
But we’re also exploring to understand an even better indicator for biodiversity because extinction rate only gives us a measure of diversity, it doesn’t give us any measure of the functions biodiversity plays.
And here I’ve just given one example of how the science it is advancing in terms of mapping out the functions that biodiversity plays for humanity.
This is illustrated from another index that is called the mean species abundance, which is an average measure of not only the number of species in each ecosystem in the world, but also how many in each species group we have grouped in terms of functions.
And here you have a map of the world of the situation, the state for biodiversity in terms of species abundance in the year 2000. And you can see in red the hotspot regions where we are truly in a very risky zone in terms of losing too much of species abundance. But in green you have regions that are still in a safe operating space.
And here you have the projections into the future, up until 2050, of the risks if we do not transgress ourselves, or if we do not move ourselves, into a safe operating space in terms of safeguarding biodiversity.
We’re right now working very actively in improving this analysis even further to say that extinction rate is a good measure of the diversity and richness of species in the world, but we’d like to have a better measure to measure and to determine the functions that biodiversity plays for human well being.
And one of these indices is a very exciting new advancement on something called the biodiversity intactness index, which is an even better measure on functional groups for the role played by ecosystems for human well-being.
And this is something that will be hopefully developed further and much more broadly in the world because so far it’s used in just a few ecosystems in the world.
But overall, in summary, biodiversity as a key for human well-being, biodiversity as a key for regulating the stability in the Earth system.
Science shows clearly that biodiversity is key to regulate a world that remains in our desired Holocene-like state, and science can now put the first quantitative estimates of a safe boundary within which we have a high likelihood of being able to rely on biodiversity, the richness of all species on Earth, as a support for human development.