Ordinarily, the Oxford Networks for the Environment (ONE) invite an external speaker to give the keynote lecture at their annual event. But, because this year’s occasion was also the launch of Oxford University’s ambitious sustainability strategy, the organisers felt that a highly distinguished internal speaker could act as a symbolic bridge between the university and the wider world.
As the ONE Chair, Jim Hall, noted in his introduction, Oxford’s Prof. Yadvinder Malhi’s reputation is truly global. Professor of Ecosystem Science at the School of Geography and the Environment, he is world-famous for his research on tropical forest ecosystems and has ongoing projects on four continents. He is a Fellow of the Royal Society as well as a recipient of the CBE.
And yet, despite all this, he is also currently working on ecosystem research and conservation in our own backyard, across the Oxfordshire county. If the key theme for this year’s event was connecting the local, national, and the global, then Yadvinder was the perfect main dish, delivered to the organisers on a silver platter.
Weight Watching: The Global Social Metabolism
‘The Concept of the Anthropocene,’ article.
After some initial comments on the growing realisation of how ‘large’ humanity is becoming, and the paradigm shift this is entailing, Yadvinder introduced the graph above. He proposes a handy way of thinking about the blue line there: Metabolism. Those of us who have struggled to gain or lose weight will likely cite our metabolisms as a key reason. When applied to sustainability though, metabolism becomes a useful indicator of the strain we place on the planet’s biosphere.
Each biological being, the plant kingdom included, has a metabolism roughly defined as all the energy flowing through it that enables it to function. When we estimate every living organism’s combined metabolism on Earth we get the biological metabolism of the biosphere. 150 terawatts is the total for all life on land, with terawatts representing a unit of energy flow per second.
In comparison to this combined figure for all of life on land, the total metabolism of humanity has long been just a small fraction. But, as you well know, over the past century and a half our numbers have skyrocketed. Obviously, the energy in our bodies (our biological metabolism) is negligible, making the problem our social metabolism. That is, the energy flowing through our infrastructure, transport systems, industrial machinery, communications networks, electrical appliances— you get the point.
While it may seem modest to some that humanity’s total metabolism in 2010 was estimated by Yadvinder as being 17% of the terrestrial biosphere’s, I’d like to remind you that we’re only one of millions of species of organism living on land. That roughly 7 billion people i.e., nearly every single person alive, could fit shoulder-to-shoulder in the city of Los Angeles alone. I think it’s something that we need regular reminders of: The world, and hence the biosphere, is so vast it’s scarcely comprehensible…
And yet, we are becoming ‘larger’.
Yadvinder calculated that, by 2050, if we follow the mid-range UN Development Program (UNDP) scenario, that our total social metabolism will be roughly one third of that 150 TW figure for all of life on land. And worse yet, if every human being were to have the same social metabolism as the average, contemporary Chinese citizen, that number would rise to 40%. I won’t even tell you what a ‘Global US’ scenario entails.
Our Embeddedness: A National Perspective
There are two ways to approach the issue: quality and quantity. By decreasing the quantity of our metabolism through more efficient energy use, saving of food, water, and electricity, and consuming less, we do the planet and ourselves a vital service. In parallel though, we also need to improve the quality of our metabolism by making it more circular and “decoupling” it from the planetary metabolism. For instance through renewables and recycling. While we can never fully decouple our metabolism from the planet’s, there is much room for improvement.
And this improvement is necessary exactly because we are embedded in the wider biosphere. Here Yadvinder cites his colleague Kate Raworth, invoking her notion of doughnut economics which rightly flips traditional economics on its head. Society and the environment are not mere externalities to an economic model that determines how we should relate to the world. Rather, the economy is embedded within society which is embedded within the environment.
Taking Raworth’s well-known ‘doughnut’ diagram, Yadvinder fills in the metabolism labels.
Local actions have national consequences which have global side-effects. As such, Yadvinder took some time to reflect on some national figures and trends. Here we learned that the UK’s social metabolism is roughly equal (91%) of its biosphere’s metabolism. The explanation for this lies largely in the fact that the UK ‘imports’ over half its metabolism from the rest of the world. It’s a potent reminder of the interconnectedness of our world today and the impact of ‘minor’ everyday decisions. An avocado eaten here contributes to the destruction of a forest over there—a problem festering terribly in Mexico.