The demand for food, feed and fuel will continue to rise as the world population grows and becomes more affluent. Meeting this demand will be especially challenging because of global warming, say climate experts, and the impacts of climate variability could make food markets even more volatile, adds Rosamond L. Naylor, professor of environmental Earth system science at Stanford University.
Naylor led a symposium on the compound effects of climate change and climate variability on food security at the annual meeting of the American Association for the Advancement of Science (AAAS) February 17th.
The symposium focused on two examples of climate variability: changes in growing-season temperature extremes beyond the range observed in the historical record, and changes in the El Niño–Southern Oscillation (ENSO) phenomenon – the most energetic form of year-to-year climate variability known.
Panelist David S. Battisti, professor of atmospheric sciences at the University of Washington, addressed key challenges in assessing the impact of extreme temperatures in coming decades. According to Battisti, global warming models forcast that temperature variability will increase as the average temperature warms, greatly compounding the likelihood of extreme heat and droughts. Unfortunately, these models typically have too much temperature variability in their simulations of present-day climate, he said. Battisti's talk focused on the cause of these modeling biases and their impact on climate forecasting.
Panelist Daniel J. Vimont, associate professor of atmospheric and oceanic sciences at the University of Wisconsin-Madison, discussed the impacts of El Niño in a warmer world. ENSO impacts can be severe in regions in and surrounding the tropical Pacific, and can extend around the globe, he said. ENSO variability – its return period and intensity – are very sensitive to changes in mean conditions in the tropical Pacific, he added, but these conditions are notoriously difficult to simulate using the present generation of global climate models. Vimont presented results from the linear ocean atmosphere model (LOAM), a new scientific tool for estimating global warming's impact on ENSO variability.
Naylor addressed the impacts of climate on global markets for major staple commodities, which are already under pressure from increased population-, income-, and energy-driven demands. She outlined the potential effects of climate variability on regional trade patterns, price volatility, policy responses and human welfare.
Mark Shwartz is the Communications/Writer at Precourt Institute for Energy at Stanford University.