Read more: “100,000 AD: Living in the deep future“
ON THE face of it, the future of the natural world looks grim. Humans are causing a mass extinction that will be among the worst in Earth’s history. Wilderness is being razed and we are filling the air, water and land with pollution.
The bottom line is that, barring a radical shift in human behaviour, our distant descendants will live in a world severely depleted of nature’s wonders.
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Biodiversity, in particular, will be hit hard. Assessments of the state of affairs make consistently depressing reading. Almost a fifth of vertebrates are classed as threatened, meaning there is a significant chance that those species will die out within 50 years.
The main cause is habitat destruction, but human-made climate change will be increasingly important. One much-discussed model estimates that between 15 and 37 per cent of species will be “committed to extinction” by 2050 () as a result of warming.
“It will be a new world,” says at the Institute of Zoology in London, UK. The ecosystem will become much simpler, dominated by a small number of widespread, populous species. Among animals that are “incompatible” with humans – we may like hunting them or colonising their habitat, for example – few will survive. “I don’t have much hope for blue macaws, pandas, rhinos or tigers,” Jones says.
Ultimately, though, life will recover: it always has. The mass extinctions of the past offer hints as to how the ecosystem will eventually bounce back, says , UK. The two that we know most about are the end-Permian extinction 252 million years ago, which wiped out 80 per cent of species, and the less severe end-Cretaceous extinction 65 million years ago, which famously took out the dinosaurs. The Permian extinction is more relevant because it was caused by massive global warming, but Benton cautions that the world was very different then, so today’s mass extinction will not play out in quite the same way.
Recoveries usually have two stages. If ours pans out in the same way, the first 2 to 3 million years will be dominated by fast-reproducing, short-lived “disaster taxa”. These will rapidly give rise to new species and bring the world’s species count back up ().
But a lot of things will still be missing. Ecosystems will be simple, with similar species doing similar things. Herbivores will be less diverse, and top predators may be absent altogether in many places.
That’s where longer-lived, slower-evolving species come in to restore the full complexity of the ecosystem. But this can take up to 10 million years, much longer than even the most optimistic projections of the human future ().
It doesn’t have to be like that. We can take action now to get the recovery going, although we don’t know how much we can accelerate it.
Conservation biologists are increasingly thinking the unthinkable, such as relocating species to places where they can thrive while abandoning them to their fate in their native ranges.
That may seem unnatural, but given that human influence has already touched almost every ecosystem on Earth, is “natural” even a useful concept any more?
Even more radically, we might be better off encouraging the formation of new species and ecosystems rather than struggling to save existing species that have no long-term future, like pandas. “There’s no way I’d want to get rid of them,” says Jones, “but things do change and adapt and die.”
Benton says the most important thing is to . That needn’t be a gargantuan task. A recent analysis suggests that damaged wetlands can be restored within two human generations ().
Beyond that it may be possible to start “evolutionary engineering”. For instance we could divide a species into two separate habitats and leave them to evolve separately, or introduce “founder” species into newly rebuilt ecosystems.
Nature may solve the problem for us by providing founder species from an unexpected source. Animals such as pigeons, rats and foxes are already flourishing alongside humans and may well give rise to new species, becoming the founders of the new ecosystem.
“Animals like pigeons, rats and foxes already flourish alongside humans and may well become the founders of a new ecosystem”
If you are disturbed by the prospect of a world colonised by armies of rapidly evolving rats and pigeons, look away now.