The Time Travel Journals: Bridgebuilders
by Marlene Dotterer
When Sam Altair went back in time to 1906, he created a second universe, one with its own alternate future. When he builds a bridge back to the original universe he finds a world in the grip of climate change, and a human population decimated by famines, wars, and pandemics. Taken prisoner, Sam must find an elusive rebel army, and use his bridges in a race to stop a deadly attack.