Wednesday, November 11, 2015

Bah Humbug! Extreme Weather and Paris COP21

In Paris in a few days time you will start to hear a lot about extreme weather and climate change. The rhetoric will be explicit: humans are the cause of more and more hurricanes, droughts, floods and pestilence.

Yet the UN’s own climate assessment organization – the International Panel on Climate Change – concluded that this was not the case. In 2012 and again in 2014 special reports from the IPCC on this exact issue concluded that the real problem was economic development. That is, more and more people and businesses are located in areas known to be prone to flooding, cyclones, hurricanes and drought. While the damage from extreme weather events are real – ask any farmer or house owner impacted by one such event. The idea that we can blame all of mankind rather than city and town planners and the individuals themselves seems alluring.

Let us be clear. This is what the IPCC has said:

  • “Overall, the most robust global changes in climate extremes are seen in measures of daily temperature, including to some extent, heat waves. Precipitation extremes also appear to be increasing, but there is large spatial variability"
  • "There is limited evidence of changes in extremes associated with other climate variables since the mid-20th century”
  • “Current datasets indicate no significant observed trends in global tropical cyclone frequency over the past century … No robust trends in annual numbers of tropical storms, hurricanes and major hurricanes counts have been identified over the past 100 years in the North Atlantic basin”
  • “In summary, there continues to be a lack of evidence and thus low confidence regarding the sign of trend in the magnitude and/or frequency of floods on a global scale”
  • “In summary, there is low confidence in observed trends in small-scale severe weather phenomena such as hail and thunderstorms because of historical data inhomogeneities and inadequacies in monitoring systems”
  • “In summary, the current assessment concludes that there is not enough evidence at present to suggest more than low confidence in a global-scale observed trend in drought or dryness (lack of rainfall) since the middle of the 20th century due to lack of direct observations, geographical inconsistencies in the trends, and dependencies of inferred trends on the index choice. Based on updated studies, AR4 conclusions regarding global increasing trends in drought since the 1970s were probably overstated. However, it is likely that the frequency and intensity of drought has increased in the Mediterranean and West Africa and decreased in central North America and north-west Australia since 1950”.
  • “In summary, confidence in large scale changes in the intensity of extreme extratropical cyclones since 1900 is low

and so it goes on.

Human “caused” climate change is not responsible for the observable increased in claimed losses due to extreme weather events, as far as we currently understand.

And that’s the key. We currently understand a little but not enough about climate to be confident about the analysis and predictions for the future. Given that the climate models in use today are running very hot when compared to actual evidence (models are not evidence), then we should be more than cautious about our understanding of climate and predicting future climates to 2100.

So when we here the certainties in Paris, question them. When we hear that climate change will cause more and more damage, challenge the speakers on the basis of the evidence from the body established to determine whether or not man-made climate change (as opposed to natural systems) are the cause of such events – and point out that this body doesn't think so.

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