Warmest Temperatures in 4,000 Years? Not So Fast!

Warmest Temperatures in 4,000 Years? Not So Fast!
April 7, 2013

James M. Taylor

James M. Taylor is senior fellow for environment and energy policy at The Heartland Institute, and... (read full bio)

The mainstream media are reporting in breathless fashion about a paper claiming current temperatures are the warmest in 4,000 years. Already, however, objective scientists are reporting serious flaws in the paper. The media may wish to paint a picture of runaway global warming, but the science tells a completely different story.

Cherry-Picking Proxies
Recently graduated Ph.D. student Shaun Marcott has published a paper claiming he compiled a proxy temperature reconstruction indicating current temperatures are the warmest in at least 4,000 years. Proxy temperature reconstructions require careful scrutiny because the proxies are not direct temperature measurements but instead represent other data and factors that may or may not have a close correlation with past temperatures.

Some proxies are better than others, and an agenda-driven researcher can easily cherry-pick certain anomalous proxies that support a predetermined conclusion while ignoring a much larger set of data that tell a different story.

Perhaps the most notorious of agenda-driven proxy reconstructions was published by global warming alarmist Michael Mann several years ago. As a young, relatively unknown recent Ph.D. graduate, Mann attained wealth, fame, and adulation among global warming alarmists by assembling a proxy temperature reconstruction that he claimed showed global temperatures underwent a steady, roughly 1,000-year decline followed by a sharp rise during the 20th century. The media reported on the Mann hockey stick reconstruction as if it settled the global warming debate, but objective scientists pointed out several crucial flaws that invalidated Mann’s claims.

Eventually, Congress commissioned distinguished statistician Edward Wegman to review and report on Mann’s methods and conclusions. After assembling a blue ribbon panel of experts to study Mann’s temperature reconstruction, Wegman reported the criticisms of Mann’s reconstruction were “valid and compelling.”

Repeat of Mann Incident
The Marcott proxy reconstruction has much in common with the Mann hockey stick. Marcott is a young, recently graduated Ph.D. student whose temperature reconstruction has launched him out of obscurity into media fame. As was the case with Mann’s hockey stick, objective scientists quickly pointed out serious flaws in the Marcott reconstruction.

Also similar to the Mann hockey stick incident, the media is ignoring the devastating critiques of the Marcott reconstruction and misleading the public into believing we finally have a study showing essentially the same thing Mann claimed before his hockey stick was discredited.

Major Flaws Discovered
Although objective scientists have had little time so far to dig into the meat of Marcott’s data, methods, and conclusions, their initial observations are devastating.

Don Easterbrook, geology professor emeritus at Western Washington University, has published two papers summarizing and documenting many of the already discovered flaws in Marcott’s reconstruction. Easterbrook reports at least one more such paper is on the way, as he and other objective scientists find more and more flaws and areas of concern in Marcott’s reconstruction as they continue to analyze it.

Easterbrook points out 80 percent of the data used by Marcott reflect oceanic data, not atmospheric temperatures. “Thus, they may reflect temperature changes from ocean upwelling, changes in ocean currents, or any one of a number of ocean variations not related to atmospheric climates,” Easterbrook writes. Marcott’s heavy dependence on oceanic rather than atmospheric proxies “in itself means that the Marcott et al. temperatures are not a reliable measure of changing atmospheric climate,” Easterbrook reports.

Easterbrook also notes Marcott recycled Mann’s proxies to help compile Marcott’s small portion of land-based proxies. Discredited proxies by any other name are still discredited proxies.

Perhaps most damaging, Easterbrook notes many other published studies and data, including analysis of extremely reliable Greenland ice core data, completely contradict Marcott’s asserted proxy data.

Science vs. Sensationalism
When many temperature studies, including research presented by the United Nations Intergovernmental Panel on Climate Change, indicate current global temperatures are cooler than the vast majority of the past 4,000 years, and then an outlier study with quickly identified serious flaws claims exactly the opposite, one would think the media would make note of the discrepancies. Unfortunately, they have demonstrated little interest in doing so. There are several likely reasons for this.

First, the news media are prone to overhype the news events of the day. Hype sells newspapers and attracts viewers. This is the case for all news topics and certainly applies to global warming.

Second, fear captivates people. This is one reason television and print news includes so much bad news and so little good news. A single breathless report of impending global warming doom will rope in more viewers and readers than a whole collection of reports explaining current temperatures are actually quite cool in historical perspective.

Third, the media drift toward advocacy of big government on many issues, and on environmental issues in particular.

Combine these three factors and you have a textbook recipe for yellow journalism—a perfect storm representing all the reasons people no longer trust the mainsteam media to be fair, balanced, or accurate.

The scientific record shows quite clearly that current temperatures are significantly cooler than the 4,000-year average, yet the media are using a seriously flawed study to claim the opposite. Global warming alarmists put their trust in the media, while global warming realists put their trust in the science.

James M. Taylor (jtaylor@heartland.org) is managing editor of Environment & Climate News. This article initially appeared at Forbes.com and is reprinted with permission.

James M. Taylor

James M. Taylor is senior fellow for environment and energy policy at The Heartland Institute, and... (read full bio)