By James M. Taylor

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A  number of professors and scientists at Iowa universities issued a Nov. 19 letter saying recent drought in Iowa is consistent with climate change. This is not surprising, considering global warming alarmists say anything and everything is consistent with climate change. A closer look at the science, however, shows the modest global warming of recent decades is reducing drought and benefiting crop production.

The central premise of the recently issued letter is that global warming is making weather events more extreme and is quite possibly causing Iowa’s recent drought. Scientists, however, have published many recent studies showing global warming is having a beneficial impact on droughts.

A 2004 study in the peer-reviewed International Journal of Climatology finds growing conditions are improving as the earth modestly warms. “The terrestrial surface is both warmer and effectively wetter … A good analogy to describe the changes in these places is that the terrestrial surface is literally becoming more like a gardener’s greenhouse,” states the peer-reviewed study.

A 2006 study in the peer-reviewed Geophysical Research Letters reports, “Droughts have, for the most part, become shorter, less frequent, and cover a smaller portion of the country over the last century.”

A 2006 study in the peer-reviewed Journal of Hydrology reports, “Evidence indicates that summer soil moisture content has increased during the last several decades at almost all sites having long-term records in the Global Soil Moisture Data Bank.”

According to National Oceanic and Atmospheric Administration, precipitation has steadily increased in the United States during the past 100 years, with the majority of the increase occurring during the summer and fall drought season.

Even a 2011 United Nations Intergovernmental Panel on Climate Change report on extreme weather events states there is “a lack of direct observations and a lack of agreement in the available scientific studies” regarding global warming and drought.

Sure, droughts will continue to occur from time to time in various places, just as they have always occurred. However, scientific evidence shows droughts are becoming less frequent and less severe as our planet modestly warms. If droughts are becoming less frequent and less severe, how can one logically say global warming is causing drought?

The authors of the alarmist letter attempt to add authority to their position by pointing out that 138 scientists signed the letter. However, more than 31,000 scientists signed a letter explaining why global warming is not causing a climate crisis. Moreover, most of the scientists signing the alarmist letter are scientists in fields that have nothing to do with atmospheric science and climatology. For example, signatories include professors/researchers in radiation oncology, genetics, English culture, anthropology, immunology, epidemiology, civil engineering and human nutrition. None of these fields has any close relationship with atmospheric physics, and few if any of these professors have professional expertise on how, why, and to what extent global warming may be impacting precipitation and drought.

The decline in drought and other harmful severe weather events is also apparent in crop production. Since 2006, according to the U.S. Department of Agriculture, U.S. farmers have set record per-acre crop yields for barley, beans, canola, corn, cotton, flaxseed, oats, peanuts, potatoes, rice, sorghum, soybeans, sugarbeets, sunflowers and wheat.

Global crop yields also are registering impressive gains as our planet modestly warms. Global grain harvests have nearly tripled during the past 50 years and nearly every important global crop has attained record productivity during the past five years.

Droughts have always occurred and will always occur. If global warming is having any influence on droughts, however, it is making droughts less frequent and less severe.

James M. Taylor is senior fellow for Environment Policy at The Heartland Institute, a research and policy organization focused on free-market solutions. Comments: jtaylor@heartland.org