If America wants to retain its position as a global power, its president must listen to the people and show strong leadership at this turning point in human history.

For the first time since life appeared on earth, one species- us- is single-handedly altering the physical, chemical and biological nature of earth. We have become a force of nature

The increasing frequency of extreme weather events, droughts and floods is in line with what climate scientists have been predicting for decades - and evidence is mounting that what's happening is more severe than predicted, and will get far worse still if we fail to act.

Any scientist who tells you they know that GMOs are safe and not to worry about it, is either ignorant of the history of science or is deliberately lying. Nobody knows what the long-term effect will be.

Faced with the evidence, many deniers have started to admit that global warming is real, but argue that humans have little or nothing to do with it.

Human beings are often at their best when responding to immediate crises - car accidents, house fires, hurricanes. We are less effective in the face of enormous but slow-moving crises such as the loss of biodiversity or climate change.

There is a gyre of discarded floating plastic the size of the continental USA in the ocean. In it, plastic trash outweighs plankton 40 to 1.