knowledge does not permit accurate specification of the dangerous level of human-made [greenhouse gases]. However, it is much lower than has commonly been assumed. If we have not already passed the dangerous level, the energy infrastructure in place ensures that we will pass it within several decades." In 2013, Hansen authored a paper called "Climate sensitivity, sea level and atmospheric carbon dioxide," in which he estimated climate sensitivity to be (3±1)°C based on Pleistocene paleoclimate data. The paper also concluded that burning all fossil fuels "would make most of the planet uninhabitable by humans." In 2016, a team of 19 researchers led by Hansen published a paper "Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming could be dangerous" describing the effect of meltwater from ice sheets on the Atlantic meridional overturning circulation (slowing it or even stopping) and Antarctic bottom water formation. This would speed up ice sheet melting and sea level rise by increasing the water temperature at hundreds of meters depth, thawing ice shelves from below. And the cool fresh meltwater on the ocean close to Greenland and Antarctica leads to larger temperature difference between tropics and middle latitudes, what would enable storms as strong as in the last interglacial, the Eemian, whose evidence includes, among others, megaboulders on Bahamas. Analysis of climate change causation Hansen noted that in determining responsibility for climate change, the effect of greenhouse gas emissions on climate is determined not by current emissions, but by accumulated emissions over the lifetime of greenhouse gases in the atmosphere. By this measure, the U.K. is still the largest single cause of climate change, followed by the U.S. and Germany, even though its current emissions are surpassed by the People's Republic of China. On public policy, Hansen is critical of what he sees as efforts to mislead the public on the issue of climate change. He points specifically to the Competitive Enterprise Institute's commercials with the tagline "carbon dioxide—they call it pollution, we call it life", and politicians who accept money from fossil-fuel interests and then describe global warming as "a great hoax." He also says that changes needed to reduce global warming do not require hardship or reduction in the quality of life, but will also produce benefits such as cleaner air and water, and growth of high-tech industries. He was a critic