Assessing "Dangerous Climate Change": Required Reduction of Carbon Emissions to Protect Young People, Future Generations and Nature

This paper, by an international team of scientists, is being published today (3/12/2013) in the open access journal PLOS ONE, where it is freely available. The paper points out the clear and present danger that today's children may be handed a deteriorating climate with consequences out of their control. However, despite the fact that governments today seem to allow and encourage extraction of almost every fossil fuel that can be found, we suggest that "there is still opportunity for humanity to exercise free will."1 Here we (Hansen and Kharecha) first summarize some of the main conclusions reached in the paper. Then in a following discussion we provide our opinion concerning more detailed policy implications Summary. We conclude that the widely accepted target of limiting human-made global climate warming to 2 degrees Celsius (3.6 degrees Fahrenheit) above the preindustrial level is too high and would subject young people, future generations and nature to irreparable harm. Carbon dioxide (CO2) emissions from fossil fuel use must be reduced rapidly to avoid irreversible consequences such as sea level rise large enough to inundate most coastal cities and extermination of many of today's species. Unabated global warming would also worsen climate extremes. In association with summer high pressure systems, warming causes stronger summer heat waves, more intense droughts, and wildfires that burn hotter. Yet because warming cause