greenhouse gas emissions. This paper elicited a critical response to Kharecha and Hansen's analysis, from an international group of senior academic energy policy analysts, including Benjamin Sovacool, M.V. Ramana, Mark Z. Jacobson, and Mark Diesendorf. They asserted that nuclear power needs large subsidies to be economically viable, and typically there are substantial construction delays and cost overruns associated with nuclear plants. Sovacool et al. also claim that Kharecha and Hansen's estimates of Chernobyl Disaster mortalities is very low, which biases their conclusions. All of these factors are said to make Kharecha and Hansen's article "incomplete and misleading". Kharecha and Hansen countered that all the data these scientists use to make their criticism, "lacks credibility". In 2013, Hansen and three other leading climate experts wrote an open letter to policy makers, saying that "continued opposition to nuclear power threatens humanity's ability to avoid dangerous climate change." The reaction from anti-nuclear environmental groups (e.g. the Natural Resources Defense Council, Sierra Club, and Greenpeace) was negative, citing nuclear safety and security issues, and the economics of nuclear power plants. Together with Michael Shellenberger, Hansen began touring the world in the late 2010s, providing evidence for the climatic benefits of nuclear energy and to bring attention to the $2 trillion the US has spent on "new renewables" that despite the cost have not even caught up to nuclear in annual electricity generation, an issue reflected in Germany and elsewhere. Honors and awards Hansen was elected to the National Academy of Sciences in 1996 for his "development of pioneering radiative transfer models and studies of planetary atmospheres; development of simplified and three-dimensional global climate models; explication of climate forcing mechanisms; analysis of current climate trends from observational data; and projections of anthropogenic impacts on the global climate system." In 2001, he received the 7th Annual Heinz Award in the Environment (endowed with US$250,000) for his research on global warming, and was listed as one of Time Magazine's 100 Most Influential People in 2006. Also in 2006, the American Association for the Advancement of Science (AAAS) selected James Hansen to receive its Award for Scientific Freedom and Responsibility "for his courageous and steadfast advocacy in support of scientists' responsibilities to communicate their scientific opinions and findings openly and honestly on matters of public importance." In 2007, Hansen shared the US$1-million Dan David Prize for "achievements having an outstanding scientific, technological, cultural or social impact on our