Human fecal matter uncovered from a lake in Guatemala reveals the Maya population living in the ancient city of Itzan declined during four different periods over the course of 3,300 years - and climate change was to blame. A team of scientists led by McGill University found the fecal matter in sediments in Laguna Itzan, which confirmed droughts plagued the area from 90 to 280 AD, 730 to 900 AD and 1350 to 950 BC, all of which saw the Maya population drop. The team also determined there was a very wet period from 400 to 210 BC, 'something which...