Mongabay: A new study shows that a major Antarctic glacier has likely passed its tipping point, putting it on track to lose 50 percent of its ice in 100 years. Such a loss is estimated to raise global sea levels by 24 centimeters (9.4 inches), according to the study published in the Proceedings of Royal Society A. Based on computer modeling, the study found that Pine Island glacier probably passed the point of no return in 1996 due to warming in the Amundsen Sea caused by climate change. If …