We are in the midst of the 6th largest extinction event in the history of the plant and the first caused by human action.

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.

Technology is a many-headed monster and perhaps it would be better to regress to a safer past and avoid technological change; it is tempting to think like that.

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.

Climate change is new and complex. We don't have all the answers.

If nuclear warfare is believed to be somewhat controlled, then climate change is now the greatest threat.

We know that the warming rising seas will swallow entire island nations that are about 25 percent of the UN vote and perhaps at the end, even our civilization. This realization is traumatic and the first reaction to trauma is denial. Since there is some remaining scientific uncertainty, a natural response is to deny that change is occurring. This is natural but it is very dangerous.