Human response to climate
Throughout history, humans have responded to climate. Take, for example, the Mayans, who, throughout the eighth and 10th centuries, were forced to move away from their major ceremonial centers after a series of multi-year droughts, bringing about agricultural expansion in Mesoamerica, and a clearing of forests. Much later, in the late 20th century, frequent droughts caused the people of Burkina Faso in West Africa to migrate from the dry north to the wetter south where they have transformed forests to croplands and cut the nation's area of natural vegetation in half.
Such land transformations, while necessary to ensure future crop productivity, can themselves have large ecological impacts, but few studies have examined their effects. To that end, a Princeton University research team has created a model to evaluate how a human response to climate change may alter the agricultural utility of land. The study, featured in Conservation Biology, provides a readily transferable method for conservation planners trying to anticipate how agriculture will be affected by such adaptations.
"Humans can transform an ecosystem much more rapidly and completely than it can be altered by shifting temperature and precipitation patterns," said Lyndon Estes, lead author and associate research scholar in the Woodrow Wilson School of International and Public Affairs. "This model provides an initial approach for understanding how agricultural land-use might shift under climate change, and therefore which currently natural areas might be converted to farming."
A Princeton University research team has created a readily transferable method for conservation planners trying to anticipate how agriculture will be affected by such adaptations. They tested their model by studying South Africa's wheat and maize production in an area projected to be vulnerable to climate change.
Before determining how climate change could impact the crops, the team first needed to determine which areas have been or might be farmed for maize and wheat. They created a land-use model based on an area's potential crop output and simulated how much of each crop was grown from 1979 to 1999 - the two decades for which historical weather data was available. They also calculated the ruggedness of each area of land, which is related to the cost of farming it. Taking all factors into account, the model provides an estimate of whether the land is likely to be profitable or unprofitable for farming.
To investigate any climate-change impacts, the team then examined the production of wheat and maize utilizing 36 different climate-response scenarios taking into account the many possible future climates and the crops response to rising levels of carbon dioxide.