After denial comes anger and finally, acceptance.

As difficult as it is to eliminate the risk of nuclear warfare, it requires fewer changes to the global economy than does averting or reversing climate change.

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.

The consensus is that climate change ranks along with nuclear warfare as the top two risks facing human civilization.

Climate change is due to the use of energy for industrial growth, which has been and is overwhelmingly based on fossil fuels.

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.

Geoengineering means changing the Earth's fundamental large-scale processes.