Derechos produce widespread and long-lived damaging wind, severely threatening life and property. We use the convection-permitting Weather Research and Forecasting model to investigate how the June 2012 North American derecho could unfold in the future with global warming. Simulations of the derecho as observed are compared with simulations under a pseudo-global warming scenario of the future environments by the end of the 21^st century following the Shared Socioeconomic Pathways (SSP5-8.5). Compared to the control simulations, the derecho shrinks and decays earlier in the future environments. The shrinkage of the derecho is attributed to the lower relative humidity on both sides of the derecho propagation path under global warming, which suppresses updraft and strengthens downdraft, impeding the spatial extent of the derecho. The premature decay is due to the intensification of an isolated deep convection (IDC) event that develops ahead of the derecho. By consuming almost all the energy and moisture on the derecho propagation path, the IDC hinders the derecho development in the mid-Atlantic coastal areas.