• Adapting North American wheat production to climatic challenges, 1839–2009
          نویسنده / نویسندگان: Alan L. Olmsteada and Paul W. Rhodeb,1

          The Intergovernmental Panel on Climate Change projects that
          temperatures in the major grain-growing areas of North America
          will rise by 3–4 °C by 2100. Such abrupt changes will create major
          challenges, significantly altering the area suitable for wheat. The
          historical record offers insight into the capability of agriculture to
          adapt to climatic challenges. Using a new county-level dataset on
          wheat production and climate norms, we show that during the
          19th and 20th centuries North American grain farmers pushed
          wheat production into environments once considered too arid,
          too variable, and too harsh to cultivate. As summary measures,
          the median annual precipitation norm of the 2007 distribution of
          North American wheat production was one-half that of the 1839
          distribution, and the median annual temperature norm was 3.7 °C
          lower. This shift, which occurred mostly before 1929, required new
          biological technologies. The Green Revolution associated with the
          pioneering work of Norman Borlaug represented an important
          advance in this longer process of biological innovation. However,
          well before the Green Revolution, generations of North American
          farmers overcame significant climatic challenges

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