In Brazil's Amazon, rivers rise to record levels

The Amazon's largest port city of Manaus flooded Tuesday as rivers swelled to levels unseen in over a century of record-keeping. The Rio Negro was at its highest level since records began in 1902, with a depth of 98 feet at the port's measuring station. The nearby Solimoes and Amazon rivers were also nearing all-time highs, flooding streets and houses in dozens of municipalities and affecting around 450,000 people in the region.

Environmental experts and organizations including the U.S. Environmental Protection Agency and the National Oceanic and Atmospheric Administration say there is strong evidence that human activity and global warming are altering the frequency and intensity of extreme weather events, including La Nina.