Along the migration route, each generation settles in a preferred egg-laying area full of milkweed, which is the only kind of plant their larvae can eat. In a sense, these animals are living out the scenario that so many science fiction writers have imagined in stories of generation ships. Each cohort goes on a journey from which they will never return home. But their offspring will eventually complete this dramatic quest.

Advertisement

What anchors this epic flight is the environment. Specifically, the butterflies require milkweed, without which they cannot return to their ancestral homes because they can't reproduce. Unfortunately, as its name implies, milkweed is a weed. As farms grow and humans take over formerly wild habitats, they destroy the milkweed that is part of the monarch's lifecycle.

Now, with very little milkweed, the monarch migration grows thin. These animals are suffering from a famine. Put another way, the process that produces their population has been perturbed. Milkweed is an input into this process; humans are an input; and all of the plants that make up agriculture are an input.

Advertisement

This year, the ancient process that produced large populations of monarchs has many new inputs. Not surprisingly, the output is different from what we saw historically.

Advertisement

Photo via US Fish and Wildlife Service

The beautiful and frustrating part about the machine that is our planet is that every output is also an input. Monarchs help fertilize plants, and when there are very few monarchs, those plants cannot reproduce. Monarchs also provide food for birds, which means that the monarch famine becomes a bird famine. Eventually this famine will get passed along to humans – especially when you consider that monarchs are just one of many insects whose populations are under threat. Bees, which pollinate a number of plants humans eat for food, are also suffering low population numbers.

Advertisement

This input/output model of understanding the environment also applies to climate. If you input carbon to our environmental system, temperatures go up and oceans become more acidic. Here, the carbon is the input while temperatures and ocean acidity are outputs.

Advertisement

Those outputs are inputs too, because temperature and acidity affect how many animals and plants develop. Shellfish, for example, have a difficult time finding the calcium necessary to build their shells in a highly acidic environment.

Advertisement

Once you realize that nature behaves like a machine, it becomes obvious that even small changes to an ecosystem can have dramatic downstream effects. It's sort of like changing one line of code in a computer program – maybe that line of code does nothing; but maybe it causes your process to crash. Maybe it leaves your entire application vulnerable to being infected by a virus.

The good news is that we are understanding how to program our planet better and better every day. Field biologists, botanists, and even paleontologists are breaking ecosystems down into their component processes, trying to understand the relationships between inputs and outputs. Microbiologists are trying to figure out how bacteria contribute to wetlands health, while forestry experts are figuring out how trees affect carbon loading in the atmosphere.

Advertisement

But the big question is when we should start trying to reprogram the Earth, to avoid disasters like famine and unwanted climate change.

When I say "reprogram," I don't mean building giant geo-engineering machines that suck in carbon and poop out oxygen — though that would be nice. I mean doing things like planting milkweed at the edge of your farm, so that the monarchs can survive. Or, to reduce carbon inputs, we might use a system called enhanced weathering, where we harness the planet's natural geological processes to increase the alkalinity of the ocean.

Advertisement

As I said earlier, nature is not the opposite of a machine. In fact, our best hope may be learning how this machine works so that we can be its very best mechanics.

Annalee Newitz is the editor-in-chief of io9, and the author of Scatter, Adapt and Remember: How Humans Will Survive a Mass Extinction.

Advertisement