Evidence-based Half Earth

The argument that half our planet should be set aside for Nature has been in the news lately. A few years’ ago, E.O. Wilson wrote Half-Earth, his plan to save the biosphere by dedicating half the planet’s surface to nature. Other scientists have published supporting arguments, for example here and here.

The idea is commendable and inspiring. Modern human civilisation is having huge, sometimes irreversible, effects on natural processes and ecosystem function. In return, the outcomes of these effects are having terrible impacts on human wellbeing, e.g. climate change, loss of natural vegetation, plastic and agrichemical pollution etc.

To sustain life, we (all of us) really need to change the way we use our local and global environments.

So is the ‘half earth’ proposal realistic and effective for achieving this goal?

Not literally; it’s too simplistic.

The half earth idea is a translation of the ‘land sparing’ argument, which recommends we intensify human activities on some areas of land and set aside other areas of land for wildlife and ‘nature’ to have free reign without humans pestering them. This argument is countered by the ‘land sharing’ school of thought, which advocates that ALL land should be shared between human needs and ‘wild nature’.

There are a couple of reasons why this simplistic debate (and all its variations) doesn’t achieve much.

~ It’s a false dichotomy. It plays on the mythical concept of ‘Nature’ as Wilderness, isolated from human society. In reality, we humans are an animal species that interact with ecosystems through our daily activities. We know that the optimal approach to managing any parcel of land depends wholly on the environmental and social context of the system. Individual land parcels are part of a broader landscape that has its own unique dynamics. Each parcel is run by individual managers who have their own unique values and goals. Landscape composition, climate dynamics, and localised management practices influence the ecosystem services available on any single parcel of land. So if you really want to generalise, a ‘both-and’ approach to sparing/sharing is much more effective than an ‘either-or’ approach.

~ It doesn’t address food security or sovereignty. Not everyone depends on the urbanised capitalist economy (a land sharing model). And this model doesn’t have a stellar record for enhancing human or ecological health. But the alternative, a ‘land sparing’ model, may be a setback for human communities that directly rely on Nature to survive, i.e. community resource governance, sustainable agriculture, hunting and gathering, nomadic/transhumant livelihoods…well, that’s every single one of us. Wherever you live, the nebulous concept of ‘Nature’ provides the ecosystem services that keep us all alive.

So instead of taking the ‘half earth’ idea literally, think of it metaphorically. Think of the whole planet. What does it mean? Half Earth implies sharing. It means we need to make decisions, based on ecological evidence, about how we use and manage our backyards, farms, gardens, towns, public spaces, and landscapes…decisions that support both nature and human wellbeing with foresight.


© Manu Saunders 2018

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