Regional Update Florida
January 27, 2008
Regional Update: Florida
Earlier this month, when flurries fell across Florida, growers feared a freeze would harm the nation’s citrus supply. Luckily, temperatures, which hovered in the 20s and 30s, did not fall below freezing for long enough to cause any long-term damage. Nevertheless, analysts are concerned about the future effects of freezes and global warming on a growing region that is so highly sensitive to changes in temperature.
As the leading national producer of citrus, sugarcane and tomatoes, agriculture adds billions of dollars to Florida’s economy. All this could change as rising global temperatures threaten to change rainfall patterns, increase the frequency of hurricanes, and alter things like water availability and soil moisture. While rising temperatures may help certain regions in the short term, adaptation to these increases in climate variability may be more difficult over time.
Dr. Shrikant Jagtap, an agroclimatologist for the College of Agricultural and Biological Engineering at the University of Florida, says that these types of climate changes in Florida agriculture can send ripples out to the entire economy. For example, last year Florida experienced a drought. Another drought is expected this year. Jagtap says this will likely lead to a suffering tomato crop and as a result, higher prices.
“Just like human beings, crops have a temperature comfort zone – what botanists call cardinal temperatures. When crops grow in a temperature outside of their comfort zone, they lose a lot of their productivity. One of the biggest problems with this situation is that heat accelerates the growing process, and the crops don’t have enough time to accumulate the correct amount of sugars and protein. Therefore, the quality of the crop – and its nutritional value – suffer,” says Jagtap.
Florida has three main climate zones – southern, central and northwest Florida. Hotter weather could be extremely damaging in the southern region, even though these same increases in temperatures may temporarily favor crop production in the northwest and central areas thanks to a process known as “carbon dioxide fertilization.” Plants use carbon dioxide for photosynthesis, so higher levels of carbon dioxide in the air could increase commercial citrus production yields by up to 70 percent in central Florida by 2100.
In southern Florida, however, results will not be as kind. Yields are expected to decrease as temperatures exceed the nominal growing range. Interestingly, even as higher temperatures spur production in central and northern Florida, freeze threats still remain. That makes citrus in those regions susceptible to injury. Citrus trees can be destroyed when temperatures fall to 28 degrees for just four hours.
For sugarcane, the effects of global warming may be even more devastating. Rising sea levels could increase flooding and damage sugarcane roots, decreasing yields by about 20%. Meanwhile, inland growing regions in areas like Louisiana may see increased yields, drawing production away from Florida’s $473 million sugarcane industry. Florida’s tomatoes face a tenuous future as well, with rising temperatures decreasing yields by as much as 44% – thus pushing more production to California.
There are other factors to consider too. Changes in climate can reduce precipitation and cause drought, which can force agriculture to compete with the water supply reserved for human use. Global warming can also help introduce more harmful weeds to the ecosystem, increasing the need for pesticides and crowding out many native plant and tree varieties. Freshwater supplies could become contaminated with saltwater. And so on.
“Population growth in the region is also causing trouble for our crops,” he says. “People like to move to Florida because of the sunny weather, and new development over the last 20 years has led to a loss of almost half a million hectares of agricultural land.”
Jagtap says that scientists are already developing crops that can withstand higher temperatures by raising their cardinal temperatures through genetic modification. By raising crop tolerance to carbon dioxide levels, growers can produce more product in less time. But there’s a downside. Crops grown in higher temperatures will still have a shortened life cycle, and that affects quality. Oranges grown at higher temperatures tend to be bitter; tomatoes tend to more acidic. Plus, the look of the crop is affected. Instead of a blood-red tomato, shoppers may find their tomatoes slightly discolored, smaller and spotted.
“Taste and quality grow with maturity,” says Jagtap.
Jagtap says that unless we can overcome some of these problems, Florida production is likely going to shift to cooler climates or to areas with cheaper labor. He says that scientifically, we can attempt to adapt to global changes in temperature to some extent, though our progress may be limited. Jagtap recommends that retailers do their part to protect the environment by cutting down on carbon emissions, recycling, and encouraging the planting of more trees.
“We’re already seeing the loss of Florida agriculture to many other areas. We’re getting more and more tomatoes imported from Brazil and Mexico now. Many other countries are exporting their products here. Florida agriculture exists in a very fragile environment that is beginning to lose its balance,” he says. “We need to stay vigilant.”