https://doi.org/10.1073/pnas.1906731117 

Abstract

Agrobiodiversity—the  variation  within  agricultural  plants,  animals,  and  practices—is  often  suggested  as  a  way  to  mitigatethe  negative  impacts  of  climate  change  on  crops  [S.  A.  Woodet al.,Trends Ecol. Evol.30, 531–539 (2015)]. Recently, increasing research and attention has focused on exploiting the intraspecific genetic variation within a crop [Hajjaret al.,Agric. Ecosyst. Envi-ron.123, 261–270 (2008)], despite few relevant tests of how this diversity modifies agricultural forecasts. Here, we quantify howi ntraspecific diversity, via cultivars, changes global projections of growing areas. We focus on a crop that spans diverse climates, has the necessary records, and is clearly impacted by climate change: winegrapes (predominantly Vitis vinifera subspeciesvinifera). We draw on long-term French records to extrapolate globally for 11 cultivars (varieties) with high diversity in a key trait for climate change  adaptation—phenology.  We  compared  scenarios  where growers  shift  to  more  climatically  suitable  cultivars  as  the  climate  warms  or  do  not  change  cultivars.  We  find  that  cultivar diversity more than halved projected losses of current winegrowing areas under a 2◦C warming scenario, decreasing areas lost from 56 to 24%. These benefits are more muted at higher warming scenarios, reducing areas lost by a third at 4◦C (85% versus58%). Our results support the potential of in situ shifting of cultivars to adapt agriculture to climate change—including in major winegrowing regions—as long as efforts to avoid higher warming scenarios are successful.