Friday, July 20, 2007

New perspectives on temperature change

There is a pressing need for new perspectives on Global Warming as the debate to date has been entirely shaped by the self serving graphics of the proponents, like the familiar one shown here. This tells us what the change has been but tells us nothing about when and where these changes have taken place within our range of seasonal variation.

The new graph below provides us with valuable new information on the exact nature and threat potential of Global Warming. The decadal change in the UK between the 1980's and 1990's produces a mean change in the order of 0.58C which exceeds the change in global mean temperatures for the past half century. The mean temperature for 1980-89 was 9.52C while the mean for 1990-99 was 10.10C. The global mean is made up of a number of such station records and it is important that we examine a station that exceeds the global mean so we can get a better understanding of how and when the actual warming has taken place.

In each decade the monthly maxima and minima are plotted with a decadal mean, maxima and minima value.

The most important thing to note is that most of the temperature increase is observed in the higher minimum monthly values rather than higher monthly maximums. And most of that has been in the winter months. For example, the lowest monthly mean for a February in the 1980's was -1.1C while the lowest February in the 1990's was +1.5C, the lowest mean for a December in the 1980's was 0.3C while the lowest mean for a December in the 1990's was 2.3C, and the lowest monthly mean for a January in the 1980's was 0.8C while the lowest mean for a January in the 1990's was 2.5C. These three months account for 0.525C of the decadal change of 0.58C.

But comparing the two decades also makes three things very clear. They are;

1 An increase in an annual mean temperature is sourced from changes that take place throughout the year, not just in the form of extreme mid summer temperatures as the climate mafia has encouraged the world to think.
2 Most of the temperature increases that contribute to a higher annual mean temperature are entirely within the normal range, in this case in the UK that is between -1.0C and +19C.

3 Of the 12 monthly maximums and 12 monthly minimums that make up an annual mean temperature figure, only two, the midsummer months, pose any sort of risk of exceeding the values that the full suite of flora and fauna at any given location have already proven they can cope with.

This latter point is critical in the light of the Climate Mafia's continually repeated claim that small changes to the global mean temperature can have far reaching implications for the biosphere. As can be observed in the UK data sets, the rise in Autumn, Winter, Spring and Summer minimum temperatures, and the rise in Autumn, Winter and Spring maximum temperatures, poses zero to minimal threat to any of the flora and fauna species that have experienced those conditions. Indeed, in most cases this is an unambiguous benefit.

And even the threat from the higher midsummer maximums has been overstated for most of the planet. In the case of plant species there is no particular temperature at which an entire forest, species or genotype will suddenly collapse and die. The weaker individuals will die off first and their death will free up soil moisture and nutrients for the remaining ones. The end result will be a slightly lower density of vegetation cover with a slight compositional change in favour of grasses rather than trees in much the same way that composition changes with latitude and rainfall at present.

The same will apply with fauna. The weak will die off first as they already do in drought with a smaller core population that will then breed vigorously in response to the next cyclical change, as they have done for millennia. So next time you hear about "major implications" from minor changes in global mean temperatures, just walk the poor dears slowly through the monthly minimums and maximums that make up an annual mean temperature and ask them which species are put at risk by suffering through a mild winter.

Ian Mott

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