Global climate change may have little or nothing to do with mankind’s burning of fossil fuels and a lot to do with sunspot cycles and other natural phenomena that aren’t affected by greenhouse gases, says Charles Wax.

And while climate variability represents a major management challenge for Mississippi farmers, “The issue of climate change that has received so much media attention has been more politics- and policy-driven than science-driven,” the Mississippi state climatologist and professor, Department of Geo Sciences, Mississippi State University, said at the annual conference of Mississippi Women in Agriculture.

Wax, who has served as president of the American Association of State Climatologists and whose interests span climatology, meteorology, hydrology, and natural resources, says variations in climate — often in only a few years — represent “much more of a threat than global warming of the magnitude we’re seeing.”

For example, he notes, in 2007 Mississippi rainfall totaled only 34 inches for the entire year, and farmers faced severe drought conditions.

“Yet, two years later in 2009, rainfall totaled 86.11 inches — two very different scenarios within just a very brief time span. A two-degree variation in average annual temperature by 2029, which some computer models are forecasting, isn’t that critical to our farmers, but a 50-inch variation in rainfall is.

“Mississippi’s humid subtropical climate, which is found in only 8 percent of the Earth, tends to result in a feast or famine rainfall situation. In 2007, from January through May we had 10 inches of rainfall. In 2009, from January through May we had 39 inches of rainfall.”

The El Niño phenomenon, which occurs every three to seven years as a result of abnormal warming of water in the equatorial Pacific Ocean, energizes storms that track through Mississippi and up into the northeast states, Wax notes.

“These usually bring wetter and colder than average winter weather over the South, as has been the case with the heavy rainfall in 2009-2010 and our quite cold winter. Human activity isn’t the reason for these weather occurrences — they’ve been happening for centuries. Temperature data for Mississippi don’t indicate any unusual warming, and our rainfall has been gradually increasing for decades.”

In Earth’s 4.6 billion-year history, there have been many climate changes, Wax notes, with changes in atmospheric composition and warming/cooling periods. “For seven-eighths of our planet’s history, we know basically zilch about climate.

“In that almost 5 billion-year period, we’ve only had instrument measurements of climate for 150 years or so and historical data for about 1,000 years. Beyond that, it’s all proxy data from tree growth rings, Arctic ice cores, etc. Carbon dioxide as a result of man’s activity covers such a small time span and is so minuscule a player in Earth’s climate as to be almost dismissible.

“We’ve only had measurements of CO2 in Earth’s atmosphere since 1958. How can we say, based on just 50 years’ data, that it is worse than ever in history? We’ve only had thermometers since the 1850s, and the farther back we go beyond that, the hazier the climate records become.

“We’ve only had satellite measurements from 1979; these show temperature variations due to natural events, but not the consistently upward trending pattern shown by land-based instruments. For that matter, major changes in instrumentation, from early thermometers to satellite measurements, affect climate data records. Depending on a particular bias, you can pretty much make these data show whatever you want to show.

“It’s just very difficult, based on widely varying data over such a relatively short period, to make a case that there that there has been an anthropogenic cause of climate change.”

CO2, Wax says, constitutes only about 3.6 percent of greenhouse gases, and “mankind’s contribution is only about 3.2 percent of that — which is a very, very small amount. Even if we doubled the amount of CO2 in the atmosphere, the percentage would be so small as to be virtually unnoticeable.”

Based on “gloom and doom” models, he says, anthropogenic CO2 emissions into the atmosphere should have had 44 percent more impact on temperature, “but they haven’t because part of it has been absorbed by oceans, forests, and other vegetation.

“CO2, because it’s such a small part of the atmosphere, isn’t a pollutant and, in fact, higher levels would increase crop production.”

There are indications, Wax says, that long-term variations in CO2 concentrations may be linked to sunspot cycles and variations in solar radiation.

“Eccentricities with the earth’s orbit around the sun and with the tilt of Earth’s axis of rotation result in stretch, roll, and wobble, and cause slight variations in solar radiation. I personally think these have as much or more impact on climate than CO2.

“Records from 1880 show CO2 levels have been rising consistently from then until now, yet there have been periods of global warming and cooling during that time that correlate with solar activity — and I don’t think CO2, or anything that man does, has had any impact on the sun. Water vapor concentrations have much more impact on atmospheric warming than CO2.”

In fact, Wax says, “for the last 20,000 years we’ve been coming out of a glacial Ice Age, and from the late 1800s through the present, we’ve been in a warming trend. But, looking at a graph of the past 500 years, indications are that “we’re overdue for another cooling cycle.”

Data from the United Kingdom’s Hadley Climate Research Unit shows that the period from January 2007 to January 2008 was the largest January-January temperature drop on record, Wax says, and that was at the height of the global warming controversy.

“Between 1400-1800, there was a ‘Little Ice Age’ during which the coldest period lasted for 70 years, and in 1815 a volcano eruption in Indonesia belched so much smoke and ash into the atmosphere that it blocked much of the sunlight and 1816 was known as the year with no summer.” In more recent times, the Mount St. Helens eruption in Washington state resulted in cooler than normal temperatures.

“Over the last century, U.S. rainfall has increased an average 1.8 inches, and at the same time we’ve seen no increase in tornadoes and hurricanes making landfall.”

An international furor has arisen over accusations that scientists with the Intergovernmental Panel on Climate Change (IPCC), whose landmark 2007 report concluded that the climate is warming and human activity is to blame, had flaws in their peer review process, financial conflicts of interest, and other shortcomings that cast doubt on their findings.

Further, it has been alleged that hacked e-mails show scientists misrepresented data on the rate of glacier melting and the increase in severe storms, and some panel members have resigned.

In resignations prior to the latest flap, scientists charged that the IPCC had “a preconceived agenda,” that its methods were scientifically unsound,” that the organization had become “politicized,” and that data had shown “no reliable long term trend” of increased storm activity and impact of global warming on storms.”

Many of the changes that have been attributed to global warming also have other underlying causes, Wax says.

“The water shortages in the Atlanta, Ga., area a couple of years ago were as much due to the huge population increases creating more demand on available water supply as to drought. The declining aquifer in the Mississippi Delta has been caused as much by increased agricultural irrigation as other causes. When there’s a drought year, there’s more irrigation, which increases demand on the aquifer and makes the situation seem worse. What we need more than worrying about global warming is to devise more ways to conserve these resources and use them more efficiently.”

e-mail: hbrandon@farmpress.com