http://www.atmos-chem-phys-discuss.net/ ... 9-2015.pdf
Humanity is rapidly extracting and burning fossil fuels without full understanding of the
consequences. Current assessments place emphasis on practical effects such as increasing extremes of heat waves, droughts, heavy rainfall, floods, and encroaching seas (IPCC, 2014; USNCA, 2014). These assessments and our recent study (Hansen et al., 2013a) conclude that there is an urgency to slow carbon dioxide (CO2) emissions, because the longevity of the carbon in the climate system (Archer, 2005) and persistence of the induced warming (Solomon et al., 2010) may lock in unavoidable highly undesirable consequences.
Despite these warnings, global CO emissions continue to increase as fossil fuels remain the primary energy source. The argument is made that it is economically and morally responsible to continue fossil fuel use for the sake of raising living standards, with expectation that humanity can adapt to climate change and find ways to minimize effects via advanced technologies.
We suggest that this viewpoint fails to appreciate the nature of the threat posed by
ice sheet instability and sea level rise. If the ocean continues to accumulate heat and in-
crease melting of marine-terminating ice shelves of Antarctica and Greenland, a point
will be reached at which it is impossible to avoid large scale ice sheet disintegration
with sea level rise of at least several meters. The economic and social cost of losing
functionality of all coastal cities is practically incalculable. We suggest that a strategic approach relying on adaptation to such consequences is unacceptable to most of humanity, so it is important to understand this threat as soon as possible.