Many of us grew up on doomsday predictions of a run‐away greenhouse effect and an ever‐expanding ozone hole. Such is life in the Anthropocene, characterized by ongoing species extinctions, habitat loss, and toxic pollution. Though the environmental movement has made progress in particular areas over the years, the biggest challenges remain unsolved. It is easy to feel depressed when looking at the impacts that humans have had on this planet.

Is it a coincidence that the science of ecology emerged as a force during a time of unprecedented environmental degradation? The past century has provided great opportunities for scientists to take notes on how to effectively deconstruct an ecosystem! Although ecology developed in this context, its future legacy could be different. Ecology can still be an optimistic science.

Rather than resisting the destruction of the natural world, the ecology of the future likely will be used as a force for creation. In essence, we can build the world we want to live in. Indeed, ecologists have already begun to recreate portions of the Earth. For example, planting an acre of trees – of the right species and in a suitable location – to sequester carbon is a noble effort, a miniature version of “geo‐engineering”. Yet there are limits to these climate‐related interventions; when scaled up across a biome, such modifications may start to resemble the heavily criticized plans to fertilize vast sections of the oceans with iron to sequester CO 2 . Similarly, restoration ecologists will continue to “restore” entire regions, such as the Everglades, though the targeted endpoints are a novel hybrid of natural form and human engineering. And evolutionary science will still be applied not only to reconstruct lineages of long‐since extinct taxa but also to help ensure the persistence of endangered extant populations. Nevertheless, as compared to older scientific disciplines, ecology has not yet translated its core theories into applications on a massive scale (as, for instance, physics has done with nuclear energy).

The time when ecological science is deliberately applied to reconstruct components of the natural world at a much broader scope may arrive sooner than you think. Imagine building, replicating, and manufacturing functional ecosystems across multiple scales, from managing selected flora in the human gut with a pill to terraforming planetary bodies across the cosmos. Engineers can create automatons through mimicry of Nature, for example by drawing inspiration for aerial drone design from insect wing morphology. The utility and aesthetics of artificial limbs can be improved to such an extent as to blur the lines between robotics and humanity. It is only a short step further to design synthetic networks across which a spectrum of natural‐to‐designed actors can then interact with each other based on competition–facilitation, evolution, or game theory. At some point, such “designed” ecosystems may even be implemented beyond the confines of this planet. We only need imagination to scale up the choices that we have already made.

The ability to create, design, and manipulate the world is fraught with peril. Yet humans have been exercising this power unknowingly for a long time, and without any methodology to identify the long‐term or unintended consequences. We have developed agriculture, domesticated several animal species, transformed huge swaths of the Earth's terrestrial surface, and even warmed its atmosphere by our activities. The difference today is that ecology gives us the framework to track, measure, and weigh the consequences of our actions. Humans are no longer designing blindly; the science of ecology can now help us, and for that reason we should be optimistic.

I believe that no matter what actions are taken, Nature will endure, and there will always be trade‐offs expressed across species, trophic levels, and scales. Whether an action is perceived as good or bad is dependent on one's valuation of these trade‐offs. We must consciously try to avoid being negative about the current state of the environment, and to remember that humans can never really deconstruct without simultaneously constructing. This point of view is not a license to destroy, nor is it Pollyannaish in naivety, but rather a call to weigh decisions using our discipline's evidence‐based framework developed over the past century.

Ecologists and environmentalists need to discuss the ethics of actively constructing and creating ecosystems. The question is not whether we will do these things but how. If ecology is not a central player in addressing these issues, other sciences will assume this role. Let's use optimism, not fear, to meet this challenge.