The question over global warming is not one that can be answered easily or with any great degree of certainty, said Charlie Wax, professor of geosciences at Mississippi State University.
“It's a very complex question — I'm not sure there is global warming,” says Wax, adding that there are many different causes and effects in weather.
This past hurricane season, he says, was part of a natural cycle in tropical cyclone activity that switched into high gear about 1995. “There are six ingredients that are needed for tropical cyclone development, and they all were above normal this season. Included among these are a low vertical wind shear, a high sea-surface temperature, and subtropical high circulation shifting west towards the Gulf. And the prediction for 2006 is almost the same as it was for 2005,” he says.
Cycles and trends, says Wax, are not the same. Cycles cause variations in things, and cycles have causes, he says.
El Nino is another factor that diminishes or enhances Atlantic hurricane activity, he explains. “Activity is up before and after an El Nino and down in an El Nino year.”
It cannot be said with certainty that hurricane activity is worse now than ever before, says Wax.
“Things have occurred that have not happened before, as far as we know. Previously, we didn't have new technology, satellites and instant reporting such as The Weather Channel. This 24-hour-per-day, seven-day-per-week reporting is driving the intensity of any perceived climate events and changes,” he says.
That's part of the answer, he says. “The annual mean U.S. hurricane is not trending, it is cycling. It shows no significant increase or decrease during the past 150 years. Climate variables play a major role.”
Several factors make it difficult to say for certainty if we are experiencing a global warming phenomenon, says Wax.
“The bad news is that I really don't know the answer. But we'll be long dead before it hits, if it does hit,” he says.
One factor that makes the issue so complicated, he says, is that weather records are not perfect. “Maximum and minimum temperatures and precipitation have been recorded at thousands of locations globally. During this time, there have been changes in instruments and in locations. Some records were even done by hand.
“There are more temperature stations now, and we may be finding things that existed before, but we just didn't know it. No matter how good our sensors are, the locations have to be right because the locations of trees and other objects can impact the findings, especially wind speed, solar radiation and rainfall data,” he says.
An unobstructed station may affect the measure of solar radiation, says Wax, and rain gauges under trees also will affect recordings.
“These are not trends but instead are obvious errors. The U.S. Historical Climatology Network is trying to go back and correct all of these errors, but only in the United States. It's the best we've got,” he says.
Temperature readings from 1880 to 2000 — with changes — show a much more dramatic increased compared to the previously unadjusted information, says Wax. “If we go back 20,000 years, it's important to remember that ‘now’ is the end of a very long story of ups and downs. It's not nearly as warm as it was in the past — 10,000 years ago — not even now. The 15th Century was as warm as the 20th Century.”
Two different people, he says, examined the same 1,000 scientific papers from many years of research and findings. “One found that 75 percent of the papers supported the consensus view that global warming is true, while the other found that only 33 percent of the papers supported the consensus view. This illustrates that we can take the same data, analyze it different ways, and support either view,” he says.
It's important to remember that the entire world will not change the same way at any given time, says Wax. “The early view is very resilient — it's all about balance. If we rebuild New Orleans, it will happen again.”