Life transforms environments, creating ecosystems where there was once only rocks. The evolution of photosynthetic bacteria billions of years ago created the atmosphere we have today, paving the way for the evolution of larger, oxygen-breathing organisms. We humans obviously transform our environment in countless ways, but can we also engineer barren environments to be hospitable to life? Can we create new living, self-sustaining ecosystems in hostile places? Can we turn lifeless planets into second Earths through the clever introduction of life forms?
Terraforming is the (currently theoretical) idea about doing just that, turning Mars or Venus into pleasant ecosystems by seeding them with communities of extremophiles or engineered microorganisms. Could hardy photosynthetic algae absorb the carbon dioxide on Venus and turn it into oxygen, creating a breathable and much cooler atmosphere with fewer greenhouse gasses? Could dark colored, cold-tolerant microorganism colonize Mars, increasing the temperature by absorbing light from the sun?
This kind of micro/macro-scopic landscape architecture is a fun thought exercise for biological engineers who like how biology can have big, hopefully positive impacts. NASA scientists have over the past few years been thinking about turning this stuff of science fiction novels into a “viable research area” and there have even been two iGEM teams (as far as I know, sorry if I missed you!) that have worked on designing organisms specifically for terraforming Mars, Valencia this year and Tokyo Tech last year.
Colonization of a human-friendly transformed Mars is, if it ever happens, obviously very far in the future, but small-scale “terraforming” here on Earth has been shown to be possible. A recent BBC article tells the story of Ascension, a tiny volcanic island in the Atlantic Ocean that was transformed from a “cinder” of an island into a lush tropical oasis during a much earlier colonial period (ht Camille!). Charles Darwin was inspired on his 1836 visit to turn the rocky island into a “Little England” for the benefit of its inhabitants. With the help of his friend Joseph Hooker he set in motion a project to plant many different species of trees high up on the island over the next several decades as the Royal Navy made the trips back and forth to the strategic island. The new plants, never before seen together in nature, captured moisture from the air, making the island more hospitable to other plants, starting a feedback loop of ecosystem formation that led to the self-sustaining forest that exists today.
We’ve done a pretty good job screwing up one planet, so I’m not the hugest fan of starting up on a different one, but I am hopeful that a better understanding and ability to engineer ecosystems and microbial communities at small scales can have a positive impact on our environment. At the smallest, most achievable level this can be as simple as composting and planting a garden but as the scales and stakes grow, so too must our understanding of the benefits and potential (although often unpredictable) risks. The adaptability and feedback that makes terraforming–and biology in general–so interesting can also make it scary. Learning from how we have changed ecosystems both positively and negatively in the past, with stories like that of Ascension but also of the introduction of invasive species and the much longer story of climate change perhaps we can solve some of our problems with a new and more thoughtful terraforming.