How to Measure the Planet’s Heartbeat | Yadvinder Malhi | TED

What do you think of when you see this forest? Maybe you think of ways the forest could be useful to us. Maybe as a source of timber or a fuel wood, or maybe as a store of carbon with which we can tackle climate change. And all of these are useful and sometimes necessary ways of thinking about a forest or any ecosystem. Or maybe, just maybe, you feel something more mysterious and wondrous. Maybe you have an inkling of a world far more ancient than our young species. A world full of beings that communicate in languages of sound and chemistry and light, that we barely understand. A world that needs to be approached with humility. In this world, plants perform the everyday miracle of turning light and air into life, and that energy that captured sunshine then cascades from plant to animal to fungus to bacterium. And on the way, it carries great currents of carbon, nitrogen and other essential nutrients that together build the web of life that is that ecosystem. And the same applies at the scale of the planet. The planet is the sum of the world's ecosystems, but it is so much more. It is an interconnected and shimmering web of flows of carbon and energy and nutrients that build up the ancient matrix that is our home, from which we have emerged as a species that nurtures us, on which we depend utterly. I'm an ecosystem ecologist, and I study this world of flows and interactions. And together with a team of ecologists around the world, we measure and map the flows of energy, of carbon and nutrients that build up the ecosystem. Starting with the capture of sunshine by plants, we follow those flows of energy to build the biomass of trees, and we follow that energy down into the roots and fungi and into the soil, and then beyond the plants and fungi, into the creatures of the soil, the worms, the invertebrates, by measuring the abundance of each creature, we can map and calculate these flows of energy. And we find every life form a miracle of evolution. Sometimes our approaches take the latest technologies, such as acoustic sensors or camera traps, coupled with artificial intelligence tools. Sometimes we use more traditional approaches, such as counting birds in a rainforest at dawn, that require training and expertise and dedication and passion. And with this type of work, we're able to build up a map of the flows that make up an ecosystem. So to take an example of this English woodland just outside of Oxford, we can calculate that 60 percent of that captured sunshine pours down into the trunks of the trees. A smaller fraction pours down from the trees through the roots into the soil. Another pathway into the soil is falling leaves in the autumn, or falling fruit. Of all that plant material, a fraction is consumed by plant-eating animals, and a smaller fraction of that is consumed by animal-eating animals, and so the web of life is built and maintained. And by doing this work in various ecosystems, we learn some things. One thing we learn is that the resilience and health of an ecosystem is determined both by the total amount of flow of energy, but also by how complex that flow of energy is, how many species it passes through. And I call this complex flow of energy the spread of energy, the vibrancy of an ecosystem. In our current work, we're also trying to go from individual ecosystems to the scale of the whole living planet, the biosphere. Here's one example which we seek to look at the biosphere through these biological eyes. And this is a map of the intensity of biological activity on the land surface. And this is for July, and the world looks vaguely familiar. Africa looks a bit strange, the Sahara has shriveled away to nothing, the southern hemispheres have shrunk away. This is January and look how different the world is. The Northern hemisphere has shriveled away into its deep, dark winter. The world is dominated by the magnificent metabolism of the tropics. We live on a tropical planet. Just look how large Kenya is there compared to all of Europe biologically. And we can do this for every month of the year. And so get a glimpse of the great green heartbeat of energy and life that powers and nourishes all life on this planet Earth. (Applause)

And through this work, I can tell you some really interesting science. And I'm here to tell you some of those scientific stories, but I'm here to do more than that. I also want to argue that this vibrancy of the living world is something that we don't pay enough attention to when we think of how we work with nature to tackle the environmental challenges we face. In conservation, we may focus excessively on particular charismatic species like elephants, or we may focus instead on what nature can do for us, its ecosystem services. And we don't pay enough attention to the webs of energy and life that hold everything together. So when we look at the world through these vibrancy eyes, some surprises can emerge. Vibrant ecosystems don't have to be places empty of people. Many cultures, traditional cultures, Indigenous people, smallholder farmers, live in places fizzing with ecological energy. And many agricultural systems, regenerative systems and others, can also buzz with ecological energy. The absence of people is not the highest state of nature. We need it in some places perhaps, but in many places people can and do build vibrant nature and we need to work with those energies. We have also learned what is not a vibrant ecosystem. Images such as this, endless rows of trees, perhaps planted for timber or for carbon capture, the richness of life reduced to a single function. All that vibrant flow of energy channeled and canalized into a single species. This is not a forest. And yet, when we think of working with nature to tackle climate change, we're in danger sometimes of focusing too much on the carbon value of nature. And carbon has a role. Certainly, there are situations where it can help us mitigate climate change and at the same time raise finance that can help us protect or restore natural ecosystems. But if we go too far, if we focus on carbon, when we stop it being a tool and it starts becoming a worldview, then we're in danger of reducing the infinities of nature into some sort of carbon machine that we can dial up and down. Here's another example of this. This is a landscape, and you may look at this and see all of those open, treeless spaces and think, well, maybe this is an opportunity for tree planting. Trees are inherently good and they absorb carbon, and maybe you can offset your company's carbon emissions with an extensive tree planting program here. But this is a savannah. And the savannah is rich precisely because of the lack of trees. It's those grasses that grow in the open spaces that provide, nourish life, provide for life-regenerating fires, and support the unique and charismatic biodiversity that is the savannah. This should not be a focus for intensive tree planting for carbon capture and climate mitigation. We need to work with vibrancy of the Earth. But why does vibrancy matter? For many reasons. But I think one of the reasons is that it gives ecosystems and all of us who depend on ecosystems, our best chance to adapt and cope with aspects of the tide of global change that is engulfing us, including from climate change. And I'd like to show one final example, which is the case of tropical atolls. Atolls are low-lying islands, less than one meter above sea level, and are often characterized as the first victims of climate change destined to drown under the rising seas in the next few decades. Or are they? We've just finished a project where we've examined these island systems, but rather than seeing them as islands in isolation, we've looked at them as integrated and interconnected island reef systems. And when we look at it that way, that view makes all the difference. So what we did is compare wild islands with ghost islands. And wild islands are places such as this, where seabirds come in to nest on the soil or in the branches of a native vegetation. And ghost islands are places such as this. Now this may look like your archetypal holiday paradise of swaying palm trees and white sand and turquoise waters, but this is an ecologically depleted system, its vibrancy is dimmed. Why is that, I hear some of you ask. It's because many of these places were once coconut plantations for an extensive coconut oil industry on these islands, which has now largely collapsed, these plantations are abandoned. But the coconut is overgrowing and suppressing the return of native vegetation. And also many of these islands are densely populated by rats brought in by sailors, which eat out the eggs of seabirds and prevent the seabirds from nesting.

So in this project, we followed the flow of energy and nutrients from the seabirds through into the forest and then beyond the forest, into the surrounding reef. And what we found is that on the wild islands, the seabirds harvested fish for hundreds of kilometers and brought in the nutrients in those fish to the islands where they deposited those nutrients in their poop, their guano, that fertilized the island. The poop and the guano then washed off into the surrounding reef and increased the rate of growth of the coral, and also the rate at which the coral bounced back from bleaching events linked to heat waves. And those higher nutrients also supported a higher abundance of fish. And of particular importance are the parrotfish, which with their beaks, they eat away at the dead coral to get at the algae inside, and in the process, they poop out the coral as sand and that parrotfish poop, that sand, then washes up to create the island. And what we found is that about up to 85 percent of the sand on these islands originated as parrotfish poop. If you're lucky enough to find yourself on a sandy, white, tropical island beach, think about the parrotfish and be grateful. (Laughter) But we also found the native vegetation doing extraordinary things that, in just one square meter of soil, the plants produced 20 kilometers of fine roots, and those roots bound the sand together and can turn that sand into nourishing soil. And so the forest was able to grow and the island to grow alongside it. So what we were able to do in this project is describe this flow of energy and sediment and nutrients from birds to island to reef and then back to islands. And when we put all our numbers together, we calculated that a wild island, a vibrant island, full of seabirds, of native vegetation and fish that aren't overharvested, those islands were able to grow at rates that keep up with mid-level scenarios of sea-level rise. But a depleted island, diminished in its vibrancy, would struggle much more and is much more likely to drown under the rising tides. But there are limits to this adaptation. The extreme levels of sea level rise would be hard to cope with, so we shouldn't use signs of adaptation as an excuse to not tackle the urgency of tackling climate change and sea-level rise. So the lesson that comes from this project is that we need to work with the vibrancy of these atoll systems to maintain and restore that vibrancy where we can, to give them their best chance of coping with climate change and for the communities that depend on them also to have the best chance of coping with rising sea level. And I think there's a wider principle that's being emerged here. It's just harder to see in most ecosystems, which are much more spatially entangled and much more complex, like this rainforest here in the Amazon, where it's really hard to predict the details of how ecosystems are going to respond to the tide of global change that is engulfing them, whether from climate change or from the other factors. What we do know is that the more we can work with the wild energies of these ecosystems, the more we can maintain and rebuild their vibrancy, the best chance they have to cope with the change that is coming and adapt to that change, and the best chance we have, as all who are dependent on these ecosystems, to adapt to that change. And that applies to wild and semi-wild ecosystems, but I believe it also applies to our agricultural systems and our urban landscapes as well. And this applies at the scale of the planet, the living Earth. We need to work with the energies of the biosphere to regenerate and restore them, to have a world that is vibrant and as possible, not a biosphere that is commodified and packaged and industrialized to be subservient to human needs, but are resilient and regenerative planet where both humans and the rest of life on Earth can thrive and flourish. Thank you. (Cheers and applause)