"We, the undersigned scientists, maintain that the case for alarm regarding climate change is grossly overstated. Surface temperature changes over the past century have been episodic and modest and there has been no net global warming for over a decade now. After controlling for population growth and property values, there has been no increase in damages from severe weather-related events. The computer models forecasting rapid temperature change abjectly fail to explain recent climate behavior. Mr. President, your characterization of the scientific facts regarding climate change and the degree of certainty informing the scientific debate is simply incorrect."
— Draft text of newspaper ad by the Cato Institute, a conservative think tank based in Washington, DC. (Thanks to Real Climate for surfacing this ad)
Cato is circulating this draft newspaper ad text to find scientists willing to sign on. It will be interesting to see how many they get and who they are.
In the meantime, let's see if we can help Cato untangle the facts.
First, the planet's temperature change over the past century has hardly been modest. Indeed, as you can see from this graph, there has been a sharp increase in average global temperature:
Along with the rising temperatures, there has already been an increasing frequency of heat waves and torrential downpours, a nearly worldwide retreat of glaciers and record loss of sea ice in the Arctic, unprecedented and damaging coral bleaching events, and many other visible impacts, as documented in the 2007 IPCC report.
As for the claim that there has been no net global warming for over a decade now, well, that's a very misleading statement. As we've posted before, 2008 may have been cooler than 2007, but it was still one of the top ten warmest years on record. And, the warmest decade on record is the last ten years.
What Cato is doing is taking the slight dip in global temperature in 2008 and comparing that to a very warm year in 1998 and saying, "See, global warming is flat." That's like saying a baseball team that won seven World Series in a row then misses the playoffs one year is just an average team.
In other words, they are ignoring the bigger picture: global warming is about the long-term trend, not fluctuations of a few years.
Indeed, the first "key message" from the recent International Scientific Congress—Climate Change: Global Risks, Challenges & Decisions conference reads:
Recent observations confirm that, given high rates of observed emissions, the worst-case IPCC scenario trajectories (or even worse) are being realised. For many key parameters, the climate system is already moving beyond the patterns of natural variability within which our society and economy have developed and thrived. These parameters include global mean surface temperature, sea-level rise, ocean and ice sheet dynamics, ocean acidification, and extreme climatic events. There is a significant risk that many of the trends will accelerate, leading to an increasing risk of abrupt or irreversible climatic shifts.
As for damage from weather events and climate models, these claims are just plain annoying.
First on the models – Cato's assertion is akin to saying that because you happened to win three straight hands of blackjack, the casino will lose over time.
Climate models are generally not designed to predict year-to-year fluctuations in weather, as we point out in great detail in this Climate 411 blog post. The purpose of climate models is to help us understand climate trends over a long period of time. Cato is purposefully confusing this point.
And, as for weather events, even the Bush administration (obviously no friend to climate action) linked increases in extreme weather events to global warming.
Not sure how many scientists Cato will get to sign onto this ad, but one thing's for sure – they've got their facts all wrong.