Why is it so difficult to solve climate change?  Imagine playing Cluedo, the game where you try to deduce how someone was murdered, where the murder was committed and who the murderer was.  But, imagine playing the game in the dark.  The murder weapon is invisible (carbon dioxide), the location doesn’t matter (carbon dioxide emitted anywhere spreads around the world) and the players (countries) are all complicit in the murder and not cooperating with the investigation.

One degree, two degrees, three degrees, four degrees……  What does it matter?  Well the world was around 5oC cooler during the last Ice Age.  At that time the ice sheets expanded to cover London.  Scotland was buried under 1,000 metres of ice.  Our climate is clearly susceptible to major climate changes from relatively minor natural changes in our orbit around the Sun.  The logic follows that our climate is also susceptible to impacts from humans. 

The negative effects of climate change do not increase steadily with each increase of one degree.  Instead they accelerate causing permanent damage.  Imagine a group of young teenagers being forced to drink litre glasses of beer.  One litre equates to a one-degree centigrade increase in temperature.  The first half litre feels good.  The group feels more sociable, life is good.  After one litre they still feel good, but it is having a noticeable effect.  It is not safe for any of them to drive as their judgement is impaired.  After two litres they are not enjoying it. They feel dizzy and stumble into each other and other people.  An argument breaks out.  After three litres they cannot think straight, are sick and cause some permanent brain damage.  After four litres all the group is unconscious.  An ambulance is called.  The world has already warmed by 1.1oC since the start of the industrial revolution.  Like the drinkers we will regret going above 1.5oC.