Using Analog Methods to Illustrate Possible Climate Change for Agricultural Producers

Changes in global climate are often described by an increase in annual mean temperature over time. The changes are frequently represented as a range, such as from 2 to 5˚C, or even more, depending on the region, the time period, and the models used. However, agricultural producers have difficulty relating changes in annual temperature to growing-season variability and production schedules. Using long-term climatic data from the National Weather Service's Cooperative Network, we have examined annual data to identify years when historical annual temperatures were one or two degrees either above or below the long-term average conditions. Then graphical representations of these changes to growing season characteristics were created to demonstrate how these changes in temperature might affect growing conditions in the future. The daily distributions of temperature identified using this analog method were expected to be more realistic than the distributions identified by simply adding (subtracting) a single degree to (from) each daily value. Analog data not only show what has happened in the past, but also can be related to historical records of how producers mitigated and adapted to the impacts of these events. These strategies could be then expanded and used to plan for future changes in climate.