Global warming and agriculture
Combustion of fossil fuels releases carbon accumulated over millions and millions of years. The carbon is released in the form of Carbon Dioxide and is accumulating in the atmosphere. The current concentration is about 400 PPM, higher that hundreds of thousands, even millions of years. Recently the EPA has begun to regulate CO2 as a pollutant.
Generally plant life requires three things to grow; soil, water, and CO2. The need for CO2 for plant growth has led some to believe that more of it is a good thing. The problem is that more CO2 means more global warming. The environmental and agricultural damage done by global warming far outweigh any beneficial effects of elevated CO2.
Agriculture is an important component of our economy, more so in Arkansas than many other states. One in six jobs are directly related to agriculture. We are number 1 in rice production, number 2 in broilers (chicken), number 3 in catfish, number 4 in saw logs (timber) and on and on for many other agriculture products.
The first and most obvious risk to agriculture is rising temperature. Rising temperatures can stress both plants and animals resulting in lower productivity. With modern mechanized agriculture and huge economies of scale, profit margins are thin. Even small changes in productivity can mean big changes in income for farmers.
One of the major projections for global warming is a change in rainfall patterns across the continent, with mid continental regions becoming drier and the coastal regions wetter.
Even if net rainfall doesn’t change there are other negative consequences related to the availability of water for agriculture. How much it rains is important but soil moisture is the real factor. Warmer air means faster evaporation from the soil and less water available to plants.
Climate instability will also impact agriculture via changing rainfall patterns. How much rain falls is important but when it rains is also important. Rain outside the growing season has much less value than rain when it’s needed.
Intense storms during the growing season damage crops. Floods, high winds and hail storms all damage crops. Tornadoes damage crops. Droughts damage crops. Much of the crops lost would have been animal feed, so all of the above damage livestock, directly or indirectly. Cattle, Broiler houses, and farrowing barns will all be negatively impacted.
Imbalances in rainfall can be partly corrected by the use of ground water, but it is already stressed in the agriculturally important grand prairie. The Sparta aquifer which underlays much of the grand prairie has already been pumped down to a dangerous degree. For over 50 years the withdrawal has exceeded recharge rates. This makes water more expensive to pump, and also may allow lateral intrusion of saline waters, requiring expensive treatment to be useful.
Overly simplistic claims like extra CO2 is good, or warmer weather is good, are at the heart of much of the denial of the risk of global warming. We face a difficult future if we don’t act now to reduce risk. Solutions are known and available, we need to act.