Analyses of wildfire-climate relationships over North America were conducted using diverse data including ground-based measurements, satellite retrievals, and re-analyses for the period 1984-2014. Results show the western US (WUS) has experienced the most robust trend in increasing burned area, even though Alaska and central Canada possess comparable or even stronger warming trends compared to WUS. In addition to warming, the WUS has been under the influence of multi-decadal trends in tropospheric relative humidity deficit, reduced cloudiness, increased surface net insolation, enhanced adiabatic warming and drying from increased tropospheric subsidence, as well as drying from enhanced off-shore low-level flow, potentially leading to more abundant dry fuels and raging large wildfires. These trends are likely the manifestation of a regional climate feedback that is enabled by the intensification, and expansion of the North Pacific Subtropical High, associated with a widening of the subsiding branch of the Hadley circulation under greenhouse warming.