This is probably a highly unlikely scenario, but I'm curious to see what comes up. Starting around the 1900s or some time after, the challenge is this: What series of events would need to occur such that fossil fuel use has been significantly, if not entirely, phased out, at least in America if globally is unfeasible. Several alternatives had already emerged, such as the selenium solar cell being invented in 1876, the world's first hydroelectric plant appearing in 1882, the first wind powered generator developed in 1888, and the first geothermal plant built in 1892. Technically speaking, the technology for alternative energy sources had already emerged as early as the 1870s. Additionally, the connection between fossil fuels and climate change had scientists concerned as early as the 1860s, so the phenomena was already understood by then. However, the biggest issue I can see is that Rockefeller and several other oil barons had already created a massively profitable monopoly on oil and coal, as well as the fact that fossil fuels have already become the number one fuel source by the time the 20th century rolls around, which I suppose is where the challenge lies. Would it be possible for a fossil fuel oriented society to forgo fossil fuels by around or some time after the beginning of the 21st century?