Terraforming our planet: an overview

Trabajo presentado en el Second IBE PhD Symposium, celebrado online el 4 y 5 de febrero de 2021.Planet Earth is currently under multiple threats because of human activity. As result of the industrial revolution, ecosystems have been dramatically altered. Released CO2 is changing the global climate by disrupting temperature regulation, oceans are acidified and polluted by plastic, and many species have become extinct because of unregulated habitat destruction (i.e. deforestation). All these external perturbations are pushing ecosystems towards their limits, so-called tipping points. Such tipping points mark critical thresholds, and once they are crossed, whole ecosystems will undergo dramatic changes in their configuration (often towards a more degraded state). A particular case where this is already happening, is semiarid ecosystems. These natural environments constitute 40% of lands and any increasing temperature will cause more aridity. This in turn, will drastically reduce the vegetated landscape, and turning them into deserts. These environmental changes promote social unrest, i.e., major migrations and wars. To improve this global situation, many interventions have being proposed, e.g. , massive replantation’s or artificial dunes fixations. Here, we propose to engineer existing microbes to promote (self-)restoration of their habitats. Theoretical results suggest that using synthetic biology to enhance microbe’s functionalities could change the ecosystem’s resilience, or even revert the ecosystem to a healthier state. By studying the general limits of ecosystem dynamics, we have found that the dynamics at the tipping point depend on the type of perturbation and the existing community structure. For instance, vegetation in semiarid ecosystems could persist at high temperatures, but eventually it will rapidly become extinct, and even without further increases in temperature. This suggests the astonishing hypothesis that Earth ecosystems could be living in the ghost of their past. Ecosystems would have crossed the threshold, already. Can we save them?Peer reviewe