‘We can adjust to climate change, but we can adjust to stop it too’

In his book. The changes, he writes, have a lot to teach us about the nature of what comes next, because this world is new to many of them, as well as many of us. Excerpts from an interview with Thor Hanson.

What are some of the common adaptations you’re seeing?

Biologists often summarize the responses to climate change with the acronym MAD, for Move, Adapt, or Die. Between 25% and 85% of species are already shifting their ranges to adjust to climate change. Even at the low end of the estimate, that’s one out of every four species on the planet. There has not been an ecological adjustment of this magnitude since the end of the last Ice Age [roughly 10,000 years ago]. In terms of adaptation, we see species changing their diets to adjust to new food sources; we see changes in bloom time, fruiting periods, insect emergence, breeding seasons, seed dispersal, hibernation, and on and on. Morphology usually changes more subtly – we see it in longer-term datasets, or by making comparisons to museum specimens collected decades or centuries ago. In certain cases, it can happen fast. Some species have alternative physiological pathways built into their DNA that can be triggered by extreme conditions. A famous example is the Humboldt squid in Mexico’s Gulf of California, where climate-driven marine heatwaves have dramatically increased water temperatures. Instead of departing for cooler waters, the squid adopted a radically different lifestyle – maturing in half the time, living half as long, and growing to only a fraction of their former size.

What are some short-term ecological repercussions of these adaptations?

Ecologically, we are in a very chaotic period. As new combinations of species come together in different places, interacting in new ways and at different times, we are in a sense creating novel ecosystems. This rapid change upends fundamental ecological relationships like pollination, predation, competition, and more. Among the most immediate and obvious challenges are what we call “timing mismatches,” where pollinators emerge after their normal flowers have bloomed, or migrating species arrive to find spring conditions and food sources far advanced from what they are used to.

Which animals are more likely than others to adapt? What can you tell us about why some species can adapt more rapidly than others?

Rapid change favours generalists, species that have specifically evolved to do well in a range of conditions. They tolerate a wide range of climates; they eat a wide range of foods; they self-pollinate. Think of successful ‘weedy’ plants like dandelions, or widespread insects and animals like cockroaches and brown rats. They’re going to be just fine. The species we worry about most are the specialists, those who have developed strategies that depend on particular environmental conditions. Bees that pollinate only certain flowers, for example, or whales that have adapted to hunt particular kinds of fish. Specialisation is a fine strategy during periods of climate stability – it allows species to carve out a dedicated niche and gain a competitive advantage. But when conditions change, those habits can become a liability.

What can we possibly expect to happen to us humans?

Our species certainly exhibits plasticity [the capacity to alter one’s behaviour, physiology, gene expression, and morphology]. We have a range of physiological responses to different conditions, from heat to cold to the thin air of higher elevations. But where we really stand out is our behavioural plasticity. We can adjust our daily habits to cope with all sorts of extremes. Aided by technology and ingenuity, we have already adapted to life on every continent and an orbiting space station. And we are already adjusting to a warmer planet. Climate change signals appear everywhere from patterns of human settlement and migration to agricultural practices, patterns of conflict, and more. In the end, we are just one more species struggling to cope, but unlike every other species on the planet, we have the ability – if we so choose – to alter the habits that are making the climate warm in the first place.