Regardless of how fast or slow you reversed the direction. Pretty much every weather pattern and ocean current on the surface of the planet would be thrown into a massive calamity. The Corolis effect and momentum imparted to surface fluids around our rotating ball is a huge, huge deal with weather flow, like the “jet stream”. It directs how storm systems (the flow of water that all life depends on) form and track and which typical track they take as the rotation of the earth is constantly deflecting them. There would be huge, unending storm systems as existing patterns now crashed head on into new ones, with storm fronts spanning entire continents. Even after the storms subsided and it settled into a new normal after 20, 30, maybe 50 years… agricultural breadbaskets would be either destroyed, completely inhospitable to their original crops, or stranded in drought. And human civilization would likely fall with them.