Mongabay: As of 2005 the Earth was already committed to rise of global mean temperatures by 2.4°C (4.3°F), concludes a new study published in the journal Proceedings of the National Academy of Sciences (PNAS). The conclusion is significant because the Intergovernmental Panel on Climate Change (IPCC) has warned that a rise in global temperature by 1 to 3°C will lead to catastrophic consequences, including “widespread loss of biodiversity, widespread deglaciation of the Greenland Ice Sheet, and a major …