Electricity cuts across an entire nation. A capital rationing water. A mayor encouraging people to shower together to save precious drops. The world’s largest river system, the Amazon, which sustains some 30 million people across eight countries, is drying up.

A record-breaking drought that is well into its second year is punishing much of South America, including the Amazon rainforest, upending lives and local economies and providing an alarming glimpse into the future as the effects of climate change become more apparent.

In Brazil, wildfires fueled by searing heat and prolonged dry conditions have consumed vast swaths of forest, wetlands and pastures, with smoke spreading to 80 percent of the country. It has led to canceled classes, hospitalizations and a black dust coating the inside of homes.

To the south, in Paraguay, the Paraguay River has hit new lows. Ships are stranded and fishermen say their most valuable quarry — including the enormous surubí catfish — have all but disappeared, forcing many people to look for work elsewhere to feed their families.

With much of South America dependent on hydropower, electricity production has plunged. In Ecuador, people are enduring energy cuts of up to 14 hours per day, knocking out the internet and sapping the country’s economy.