No single extreme weather event can be linked to climate change.
However, when there are a series of unusual catastrophes, it raises questions about the impact that carbon-dioxide emissions are having on the planet.
This year, two of those disasters have occurred in areas represented by North America's most intransigient climate-change-denying politicians.
Devastating tornadoes turned a suburb of Oklahoma into kindling.
Ironically, Oklahoma senator James Inhofe has been called "the standard-bearer for climate contrarians in Congress" by New York Times energy blogger Justin Gillis.
Inhofe even wrote a book called The Greatest Hoax: How the Global Warming Conspiracy Threatens Our Future. Not surprisingly, he's been the beneficiary of massive campaign donations over the years from the fossil-fuel industry.
The junior senator from Oklahoma, Republican Tom Coburn, is another climate-change dinosaur. He voted against factoring global warming into federal project planning and opposed starting implementation of the Kyoto Protocol.
Calgary experiences dramatic flooding
Over the past 24 hours, massive floods have occurred in Alberta, which is Canada's centre of climate-change denial.
Approximately 75,000 people were evacuated from their homes in Calgary as river levels rose sharply after massive rainfall.
In the past, Calgary West Conservative MP Rob Anders—perhaps Canada's most right-wing parliamentarian—has characterized a carbon tax and cap-and-trade emissions trading as "socialist policies".
His boss, Prime Minister and Calgary Southwest MP Stephen Harper, has muzzled government scientists and refused to seriously address climate change.
With Harper leading the nation, Canada routinely wins the most Fossil of the Year awards at international climate conferences—prizes that Harper's environment minister, Peter Kent, says should be "worn with honour".
Politics of climate change
All it takes is for one massive climate catastrophe to turn an election.
Hurricane Sandy did the trick for Barack Obama. It shone a light on Republican Mitt Romney's climate-change denial in the days leading up to the last U.S. presidential election.
The reality is climate change is all about the math. When greenhouse-gas levels reach a certain threshold in the atmosphere, weird things start happening on Earth.
To deny that is to deny that one plus one equals two.
Most voters can easily figure that out when they see their homes and motor vehicles floating down a river.