On 11 December, the US Congress Committee on Science, Space, and Technology (labeled by many the House Anti-Science Committee for the unscientific views of many of its Republican members) held a hearing on the link between climate change and extreme weather events. Unfortunately, like many such hearings, the purpose of the event appeared to be more about reinforcing preconceived notions than educating committee members. This was made clear by a simple examination of the invited witnesses.

The Republicans on the committee invited two witnesses, John Christy and Roger Pielke Jr. House Republicans regularly invite Christy to testify on climate issues, because he's one of the less than 3 percent of climate experts whose research indicates that the human contribution to global warming is relatively small. Christy also reliably provides factually inaccurate testimony at these hearings, and this time around was no exception. In fact, Christy led off his written testimony with the following myth:

"As the global temperature failed to warm over the past 15 years..."

John Christy and Roy Spencer compile satellite measurements of the temperature of the Earth's atmosphere at the University of Alabama at Huntsville (UAH). Their data set estimates the warming of the lowest layer of the Earth's atmosphere at 0.21°C over the past 15 years, so Christy's opening statement is in direct contradiction with his own data. New estimates of average global surface temperatures also put the value at about 0.21°C global surface warming over the past 15 years.

Additionally, the warming of the atmosphere only accounts for about 2 percent of the warming of the global climate, which as a whole has accumulated heat at a rate equivalent to 4 Hiroshima atomic bomb detonations per second over the past 15 years. Perhaps the House Republicans keep inviting Christy to testify because he tells them what they want to hear regardless of its factual accuracy.

Global heat accumulation from Nuccitelli et al. (2012)

Roger Pielke Jr. was more factually accurate with his testimony, but conveniently for those who favor climate inaction, he's known for downplaying the link between human-caused climate change and extreme weather events. This link is often difficult to make because our records of some types of extreme weather measurements aren't very good, and because it's difficult to tease out human contributions from natural variation. Pielke tends to focus on the links we can't yet make while downplaying or ignoring the links that we can.

For example, human-caused global warming has increased the frequency and/or intensity of heat waves, extreme storms, floods in some areas, and droughts in some areas. We know that hurricane intensity in the North Atlantic has increased, and is expected to continue increasing as global warming continues, because warmer oceans are fuel for hurricanes. New preliminary research from James Elsner suggests that US tornadoes may be becoming more intense, and a new paper led by Kevin Trenberth suggests that global warming will also make droughts more intense.

Pielke also claimed,

"The United States is currently in a remarkable stretch with no major hurricane (Category 3+) landfalls"

While Sandy was technically a Category 1 storm when it made landfall, it was also more energetic than Hurricane Katrina at landfall, and inflicted about $50bn in damages. People living in New Jersey and New York would likely object to the claim that Sandy was not a major hurricane.

To counter the testimony from the Republican witnesses downplaying the risks from climate-amplified extreme weather, Democrats invited retired Navy Rear Admiral David Titley, who's now the director of the Center for Solutions to Weather and Climate Risk at Penn State. As his title suggests, Titley focused on approaching the problem from a risk management perspective. In his written testimony, Titley noted,

"The Absence of Evidence is not the Evidence of Absence ... to ignore the possibility of change is the same as assuming we have high confidence there will be no change - and that is simply not true."

In other words, while we can't yet confidently link human-caused climate change to some types of extreme weather, that doesn't necessarily mean there is no link. Titley also used his military background to draw an analogy to risk management in national defense, showing the following chart.

Decreasing worldwide battle deaths over time. Image source: Wall Street Journal

Titley noted,

"If these statistics are the climate-equivalent of extreme events, one might be tempted to say we no longer have a need to invest in our military or domestic security programs. That would of course be ridiculous; we rightly invest in our security and defense as one component of hedging against unknown or unlikely security risks."

Titley is right that whether we like it or not, climate change is a risk management problem. Those who favor inaction are putting all their chips on the best case scenario, hoping that the most likely and worst case scenarios don't come to fruition. It's akin to driving around in a turbo-charged sports car without purchasing auto or health insurance because one mechanic and one doctor out of 30 said you'll probably be fine.

It's quite simply a massive risk management failure. With something as important as the global climate, on which every living being on the planet relies, we should be overly cautious, not impetuous and reckless. Titley is exactly right on this point, and fortunately was able to make this case to the House committee. Unfortunately the House Republican take-home message was exactly as you might expect, with their summary of the hearing reading,

"Little Evidence Linking Climate Change to Extreme Weather Events"

It doesn't have to be this way. Somehow Republicans need to return to their conservative roots when it comes to climate change. Betting our future climate on the hopes that the absolute best case scenario (which still involves significant human-caused climate change) is a total failure of risk management. There are solutions available that many conservatives support, like a revenue-neutral carbon tax. But as long as Republicans in Congress continue denying that the problem exists and ignoring the risks it poses, they're playing a dangerous game of Russian roulette with our future.