Gord Miller

February 03, 2011 - The climate change models have always predicted that one of the outcomes to expect from a warming climate is more extreme weather events.  And, looking at world events in recent years, there certainly seems to be an increase in storms, floods, droughts, extreme temperatures and large forest fires.

But perhaps this is just a perception brought about by our much increased interconnectedness. Are we just better informed about events going on around the globe, so it seems like they are increasing?

The one institution in society that has to know exactly what is going on with respect to extreme weather events is the insurance industry. Their whole economic survival depends on guessing in advance the risk of large damaging weather events. If they get it wrong it can cost them billions. It's no surprise then that they track and enumerate such occurrences.

The graph below was recently published by Munich Re, one of the world's largest reinsurance companies. It clearly shows that natural catastrophes have increased substantially over the last 30 years with a trend line on the upswing. These data include all natural events not just those related to climate and/or weather.

But look! Geophysical events such as earthquakes, tsunamis and volcanic eruptions show no pattern of increase. All the increase is due to meteorological, hydrological and climatological events which have all more than doubled. From an insurance point of view it certainly looks like the climate is changing.

So why is it that when an extreme weather event occurs scientists declare that you can't say that any particular weather event was the result of climate change? James Hansen, the preeminent climate scientist from NASA, recently blogged (.pdf) on that question this way:

Finally, a comment on frequently asked questions of the sort: Was global warming the cause of the 2010 heat wave in Moscow, the 2003 heat wave in Europe, the all-time record high temperatures reached in many Asian nations in 2010, the incredible Pakistan flood in 2010? The standard scientist answer is "you cannot blame a specific weather/climate event on global warming." That answer, to the public, translates as "no".

However, if the question were posed as "would these events have occurred if atmospheric carbon dioxide had remained at its pre-industrial level of 280 ppm?", an appropriate answer in that case is "almost certainly not." That answer, to the public, translates as "yes", i.e., humans probably bear a responsibility for the extreme event.

In either case, the scientist usually goes on to say something about probabilities and how those are changing because of global warming. But the extended discussion, to much of the public, is chatter. The initial answer is all important.

So it is very important to be conscious of how you structure the message if you want to engage in the great climate change debate. But one thing seems apparent in these confusing times of sceptics, deniers, trolls and obfuscators. Gaia doesn't care what we hairless apes think. She will just keep whacking us with weather until we start behaving.

Gord Miller is the Environmental Commissioner of Ontario