Global warming could significantly affect Texas ag output over next century

By JULIET BRISKIN | Staff writer

Feb. 19, 2004 -- The effects of climate change is an issue that touches every aspect of life in 2004 and is a critical issue for agriculture around the globe. Due to the increased levels of greenhouse gasses released into the atmosphere, solar radiation and heat have been trapped raising the average temperature of the earth. This phenomenon, known as global warming, is predicted to continue heating the Earth.

According to the Environmental Protection Agency (EPA), model calculations suggest global temperatures could rise between 1.6 degrees Fahrenheit (F) and 6.3 degrees F by 2100. Texas could experience, on average, a 3-degree F increase in spring and a 4-degree F increase in other seasons. Due to this temperature increase, the EPA estimates that Texas' agricultural output could fall by as much as 25 percent over the next century.

It is predicted that Texas will experience more frequent and intense rainfall with longer dry periods in between, and as much as a 17-inch rise in sea level along the Gulf Coast.

Numerous studies on the impact of global climate change on crops have been conducted by scientists around the globe. The results of these studies vary, but the consensus is that global temperatures are rising. Global warming is caused by human activity and will result in agricultural shifts and changes worldwide, studies cite.

Beth Lemberg-Hima of the USDA Agricultural Research Service has co-authored a report analyzing the economics of climate change on cotton production across the U.S. cotton belt and presented the report at the 2004 Beltwide Cotton Conferences in San Antonio.

In her presentation, Lemberg-Hima explained that locality matters when discussing the impacts of climate change on cotton production. "The bio-physical and climatic specifics of a locality play a large role in yield response to climate change," she stated.

In a paper released by the Pew Center on Global Climate Change, it is reported that "temperature increases can have both positive and negative effects on crop yields, with the difference depending in part on location and on the magnitude of the increase. Crop yields in the northern United States and Canada may increase, but yields in the already warm, low-latitude regions of the southern United States are likely to decline."

Not only does locality play a vital role in determining crop yields under increased global temperatures, so does the individual crop itself.

"The effects of climate on yield levels and variances are shown to vary depending on the crop. For sorghum, more rainfall and higher temperatures increase yields while increasing yield variability. Precipitation and temperature individually have opposite effects on corn yield levels and variability," explains a 2001 report co-authored by Dr. Bruce McCarl of Texas A&M University.

According to the Pew Center, it is difficult to predict with absolute certainty the effects of increased temperatures on agriculture and more research is needed. An EPA report on global climate change explains that "developing the ability to confidently estimate the impacts of climate change on agriculture is critically important. It could provide the global information needed to help farmers develop their own long-range responses to climate change."

What is for certain, according to McCarl and his co-authors, is that climate is a primary determinant of agricultural productivity and increases in global temperature will have an impact on the industry. But, they explain, farmers may adapt by changing planting dates, substituting crops, changing irrigation practices, and changing land allocations among crop production, pasture and other uses.

With 2002 and 2003 tied as the second hottest years, worldwide, since 1880, global warming represents a real challenge. U.N. Weapons Inspector Hans Blix stated in March 2003 that "the question of the environment is more ominous that that of peace and war.... I'm more worried about global warming than I am of any major military conflict."