To survive, humans need food, water, and air. Yet biodiversity, the Earth's bodies of water, and the planet's atmosphere are all under threat.

The sun is the source of all energy on planet Earth and we cannot experiment with our only energy source.

Signs of a poorly understood but treatable house fire requires action, not inaction.

Even if we planted a tree on every square yard available in the planet by the end of the century we would only capture at most 10 percent of the CO2 we need to reduce. This does not mean that we should not plant trees; we should, for biodiversity's sake, and for our long-term future together with the other species.

We know little of the consequences of the geoengineering process, such as spraying particles into the atmosphere that shade the planet from the sun's rays and could decrease its temperature. But this process is how dinosaurs disappeared from the Earth about 60 million years ago, by particles spewed by a volcano or a giant meteorite impact, and our species could follow suit.

The "can do" logic, by its own nature, does not accept limits. And an empire does not have a graceful way to evolve out of this role. History demonstrates this time and again.

The new markets that arise from ecological constraints will dominate the 21st century economy, and so will markets for knowledge.