Associated Press: Global warming could kill off half of the tree species in Brazil’s vast Amazon jungle by 2050, a leading international climate change expert said Wednesday. A worst-case rise of 4 degrees Celsius (7.2 degrees Fahrenheit) would wipe out half of the region’s tree species by making the Amazon much drier and causing increased humidity in Brazil’s non-Amazon southern region, said Martin Parry of the U.N’s Intergovernmental Panel on Climate Change. A lower rise of 2 degrees Celsius …