National Center for Science Education, an organization noted for defending the teaching of evolution in United States science classrooms, named Hansen as an advisor to support the extension of its area of concern into the teaching of climate change. Keystone Pipeline In a CBC interview aired in April 2013, as Canadian Natural Resources Minister Joe Oliver lobbied in Washington, DC for approval of the Keystone pipeline extension intended to carry more synthetic crude oil from Canada's Athabasca Oil Sands to the Gulf of Mexico, Hansen forcefully argued against the use of these unconventional fossil fuels. According to Intergovernmental Panel on Climate Change (IPCC) and other energy organizations "there is more than twice as much carbon in the tar sands oil" than in conventional oil. Hansen argued that coal, tar sands, and tar shale should not be used as energy sources because of their carbon emissions and claimed that the completion of the Keystone pipeline would increase the extraction of oil from oil sands. He explained that the effects of climate change may not be apparent until the far future: "It's not the case where you emit something and you see the effect. We see the beginnings of the effect but the large impacts are going to be in future decades and that science is crystal clear … Effects come slowly because of the inertia of the climate system. It takes decades, even centuries to get the full response. But we know the last time the world was 2 degrees warmer, sea level was 6 meters or 20 feet higher." Hansen urged President Obama to reject the Keystone pipeline extension intended to carry more synthetic crude oil from Canada's Athabasca Oil Sands to the Gulf of Mexico. On February 13, 2013, Hansen was again arrested at the White House, along with Daryl Hannah and Robert F. Kennedy, Jr., during a further protest against the proposed Keystone pipeline extension. Proposed solutions Recently Hansen stated his support for a revenue-neutral fee and dividend system to impose a price on carbon that returns the money collected from the fossil fuel industry equally to all legal residents of the United States. In an interview on CBC television on March 3, 2015, Dr Hansen stated "The solution [to climate change] has to be a rising price on carbon and then the really dirty fuels like tar sands would fall on the table very quickly. They make