CNN reporting is the absolute worst, crap reporting out there.

"It’s still early to determine the cause of this extreme event but according to our experts, it is certainly connected to the drought period and high temperatures in Lake Tefé, in which some points are exceeding 39 degrees Celsius (102 degrees Fahrenheit),” the institute said in comments carried by CNN affiliate CNN Brasil."

It's the drought and that is causing the temperature of the water to increase, too, not just the "global warming" bearing down on a roaring Amazon, slaying dolphins left and right.

Yellow journalism at its finest.