UN report says most climate change effects are 'unprecedented' and 'irreversible'

It's no longer possible to prevent the planet from heating over the next 20 to 30 years, and some of the changes global warming is bringing about are now impossible to undo in the short term, according to a new report from the United Nations' Intergovernmental Panel on Climate Change (IPCC). The document represents the most comprehensive analysis of the physical science behind climate change ever amassed in human history. The 284 scientists who worked on the project spent eight years examing dat...