Wildfire is a natural phenomenon that began with the development of terrestrial vegetation in a lightning-filled atmosphere. It is a global-scale phenomenon that shows itself in Carboniferous period sediments from 350 million years ago. As human populations developed in the Pleistocene and Holocene epochs, mankind transformed fire into one of its oldest tools. Recent scientific findings have bolstered the hypothesis that climate change is resulting in fire seasons starting earlier, lasting longer, burning greater areas, and being more severe. A negative impact of prime concern in the 21st Century is desertification. This term refers to land degradation, not the immediate creation of classical deserts. It is about the loss of the land's proper hydrologic function and biological productivity as a result of human activities and climate change. It affects one third of the earth's surface and over a billion people. . In the past it was considered a problem of only arid, semi-arid, and dry sub-humid areas. However, humid zones can undergo desertification with the wrong combination of human impacts. Fire-related desertification has consequences in terms of environmental, social, and economic costs. The two key environmental consequences are soil erosion and exotic plant invasions. This paper discusses the impacts and consequences of wildfires and improper prescribed fires that lead to post-fire erosion and desertification. The focus is on the Rodeo-Chediski Wildfire of 2002 that burned nearly 200,000 ha of forest land in Arizona, but it also examines fires elsewhere in the USA and the world.