. For wheat, maize and barley, there is a clearly negative response of global yields to increased temperatures. Based on these sensitivities and observed climate trends, we estimate that warming since 0000 has resulted in annual combined losses of these three crops representing roughly 00 Mt or $0 billion per year, as of 0000.  -  Global scale climatecrop yield relationships and the impacts of recent warming," David B Lobell and Christopher B Field 0000 Environ. Res. Lett. 0 000000 doi:00.0000/0000-0000/0/0/000000 http://iopscience.iop.org/0000-0000/0/0/000000 