Climate change, chaos theory and semantics.

Parts of the northern hemisphere are facing widespread devastation as a result of weather developing in the northern hemisphere.

Domino man

In addition to storms in the US and UK, there are also predictions that the  winter temperature in the Arctic will go above freezing point in mid-winter. If this continues, then we can expect the normal summer melting of the ice caps to be extended into winter, with calamitous consequences.

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No one has been able to predict what the impact of changing temperatures over the Arctic ice cap will be but already the lunatic fringe is saying that this situation is just a “random spike” in the weather patterns.

Events in the UK, US and here in Australia indicate that the severity of the “once in 100 years” events is increasing and that the hundred year time-frame is shortening drastically.

To understand the nature of the changes to our climate it’s worth going back to look at the work of Edward Lorenz, a meteorologist and a pioneer of chaos theory.

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Lorenz developed the ideas of chaos theory as result of his work as a meteorologist so chaos theory has direct relevance to our understanding of the way that the climate works and changes.

One of the central ideas that Lorenz developed was the idea of sensitivity to initial conditions.  

This means that in systems that are closely linked and involve large numbers of interactions (such as weather systems), small changes to the starting state of the system can lead to widely divergent results at any time in the future.

This idea gave rise to  Philip Merilees asking Does the flap of a butterfly’s wings in Brazil set off a tornado in Texas?,  now known as the Butterfly Effect.

The idea of initial conditions is slightly misleading. Most systems don’t have initial conditions rather they have conditions at any given point in time.  It simply depends on where you start counting from.

This means that large weather systems such as the one that is developing in the northern hemisphere have their origins  in one, or a number of, small-scale events somewhere else in the world.

If we consider that these events will initially occur at a molecular level, then the number of possibilities is astronomically large and unpredictable.

I’ll come back to the idea of predictability later.

When large-scale events such as the “cyclone bomb”  occur, they trigger a huge range of changes to the initial conditions of other parts of the system. These small changes then build into large-scale events in a reinforcing feedback loop.

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This is why we can expect the consequences of climate change, floods, bush fires etc to become more frequent and more extreme.

Many of the climate sceptics described these weather events as “random”. It’s important to understand exactly what this word does and doesn’t mean.

The most important meaning is that random events are not predicted, they are unexpected and often difficult to explain.

But they are not without causation.

Something always causes a random event. We may not know what it is but nothing ever occurs without a cause. When climate sceptics use the word random, they are implying that the events are without any cause, in particular they are not a result of any human actions.

This is a dangerous fallacy.

Weather events are not without cause but are part of a dynamic feedback mechanism that covers the entire globe which generates its own behaviour.

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Now,  man-made carbon emissions have added an extra variable, another large-scale initial condition, to this dynamic system.

Before man began polluting the atmosphere, the weather system was in  long-term equilibrium. Hot in the summer, cold winter, colder at the poles and warmer of the equator. The idea of equilibrium does not mean that everything is calm, it simply means that things are in balance.

Now that equilibrium has been disturbed and the temperature at the poles is ceasing to be significantly colder than the temperature in other parts of the world.

We need to understand very clearly how carbon emissions are disturbing the equilibrium  of our weather system and that it is moving towards a new equilibrium will involve more events such as storms in the UK and US, rising sea levels in coastal areas and increasingly severe floods and bush fires in Australia and California.

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