The Climate Change Debate

There is always a debate about climate change. Sometimes the debate is loud and vigorous. At other times the debate is hard to hear above the alarums and excursions that are part of our lives in a rapidly changing economic world. There are two separate questions to the climate change debate. Traditionally these two questions are expressed simply for mass consumption in the press, radio and television as:-

  1. Is the climate changing at all?
  2. If it is changing what are the causes of the change?

We have to be careful to define our terms because the climate has always changed, so we can make the debate futile by applying terms literally. In fact the questions are more correctly expressed with less shorthand and more accuracy:-

  1. Is the climate changing significantly more rapidly that it has ever changed, to our knowledge? In this facet “significantly” means by a factor of ten or twenty times.
  2.  Apart from all the known possible natural causes of climate change are there anthropological causes?

You can think of climate change in the same terms as evolution of species. It may have taken humanity millions of years to evolve from a primitive vertebrate into the rather sophisticated biological entity that humanity is today. These changes took place slowly. It has taken our climate millions of years to evolve into its present state and that climate evolution went hand in hand with natural evolution of species, with the natural climate changes dragging the species to evolve.

A change in the climate was caused by a natural process, such as fewer volcanoes erupting or the sun becoming temporarily more intense or a combination of many natural factors. These created conditions to which life had to adapt, and so we today see many different forms of life in different places naturally occurring. Polar bears and seals are adapted to life in cold regions; temperate regions have different forms of life and equatorial regions have different forms. Similarly there are different forms of life on high mountains and in deep seas. A changed climate creates different life, and as the climate change was slow so the life forms had time to evolve and adapt. A person would rarely see species move out of a given environment during his or her lifetime, because the pace of change of the climate was so slow. The climate moves and drags life after her.

Today we do not see organisms evolve terribly quickly, except it seems for bacteria and viruses, but we do see organisms move. They move in response to a changed climate; the changes are small but the life forms have taken millions of years to adapt to a given climate and so when the life forms find a small but rapid change in a local climate it is possible for them to move to a nearby climate which retains the features of the climate in which they prospered.

Sometimes the species move to higher ground; it seems that most species are on average moving to higher ground at the rate of 11 metres every ten years. Other species move to a different place, usually northwards, at the rate of nearly 17 kilometres every ten years. Some parts of the planet are warming more quickly than others and in those parts that are warming faster the shift of species is faster.

Studies to this effect have been published in Science. It is part of the evidence that the answer to the first question – is the climate changing more quickly – is likely to be yes.

The second question is about what is causing this change. So far, we can rule out known natural causes of rapid climate change. What else is left?That is what the real climate change debate is all about.

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