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

The first reaction to trauma is denial, then comes anger and finally, acceptance. I think the US is still between denial and anger, and I hope we will reach acceptance because almost perversely, right now, only the US has the technology that is needed for global economic change.

We have used the majority of our carbon budget and we are already at dangerous levels of CO2 concentrations, about 400 parts per million. The levels were 250 before industrialization. So the problem is what we have done already and, therefore, what must be undone.

We are still learning how exactly the Earth reacts to increased CO2 and other greenhouse gases. We know it leads to warming seas which are melting the North and the South Poles, rising and starting to swallow entire coastal areas in the US and elsewhere, as the New York Times article documents.

Changing an economic system that is bent on uncontrolled and poorly measured economic growth and depends on fossil energy for its main objectives, is much more difficult than changing how nuclear energy is used for military purposes. Some think it may be impossible.

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

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