[Global Change: 3822] Re: Climate Risk Policy for Sceptics

I think there are actually 2 sciences of climate – the science of
global warming and the science of abrupt climate change - and the 2
are mutually incompatible.  The Intergovernmental Panel on Climate
Changes (IPCC) defines weather as chaotic.  Chaos theory is one of the
3 great ideas, along with relativity and quantum mechanics, of 20th
Century physics.  The ideas are all counter intuitive but are based on
observation.  In the case of chaos theory – Edward Lorenz in the
1960’s noticed that an odd thing happened when he changed the input of
his computer convection model slightly - the result of the calculation
changed by a lot.  This led to identification of the butterfly effect
– poetically expressed as a butterfly flapping its wings in Brazil
causing a tornado in Texas – small initial changes causing dramatic
and abrupt shifts in complex and dynamic systems such as weather.  It
is the reason why weather can’t be predicted beyond about a week.
Climate, on the other hand, is defined by the IPCC as the ‘average of
weather’.  On average, if a little carbon is added to the atmosphere
the world will be a little warmer regardless of what the weather is
doing at any one time – global warming.  Independently of the reality
or otherwise of an average climate - it should be noted that modern
climate models use the same partial differential equations of fluid
motion used by Lorenz.  Climate models are themselves complex and
dynamic systems – small changes (well within the limits of
plausibility) in inputs produce radically different answers.  What was
that result again?

The US National Academy of Sciences published a report called “Abrupt
Climate Change: Inevitable Surprises”.  It is based both on
paleoclimatic proxy data and modern climate records and identifies
mechanisms and examples of abrupt climate change from ancient times to
the modern era.  The definition of abrupt climate change is that small