Policy-makers should carefully consider the implications of the pause or “hiatus” in global warming when crafting climate policy, concludes a new study released today by the Fraser Institute, an independent, non-partisan Canadian public policy think-tank.
The study, Climate Policy Implications of the Hiatus in Global Warming, spotlights the warming hiatus, and what it means for public policy in Canada and around the world.
“Many politicians, journalists and others claim the climate is warming faster than expected. But over the past two decades, the pace of warming has actually slowed well below almost all model projections, and the implications for climate policy have not been adequately discussed,” said Ross McKitrick, study author, Fraser Institute senior fellow and economics professor at the University of Guelph.
There has been no statistically significant temperature change over the past 15 to 20 years (exact length of the hiatus depends on the data source) despite an 11 per cent increase in atmospheric greenhouse gas levels since 1995, driven primarily by carbon dioxide (CO¬2) emissions from cars, power plants and other manmade sources.
Crucially, in countries like Canada, greenhouse gas policy analysis relies heavily on climate models (computer simulations that predict warming trends), which project temperature changes based on greenhouse gas levels.
But several recent scientific studies, notes McKitrick, found that greenhouse gases have less effect on climate than most climate models project. And the gap between climate models (with their projected temperatures) and reality (actual temperatures) continues to grow.
The result? Policy-makers risk overestimating the harmful effects of CO¬2, and as a result, may set inappropriate policy targets. McKitrick also notes that climate policies (carbon taxes, for example) often involve long-term commitments from governments with no provision for adjusting to new information or scientific development.
So what should policy-makers do, in light of the warming hiatus?
“Over the next few years, as evidence mounts, climate models may change dramatically. If policy-makers want to craft sound climate policy, they should await the outcome of this process, and any long-term plan should be adaptable to new data about the effects of CO¬2 emissions,” McKitrick said.
“The global warming hiatus is real and has implications for policy design that have not yet been taken into account. A failure to recognize the scientific evidence may prove costly for Canada and other countries around the world.”