It was decades ago that warnings about global climate change began to emerge, and not long after that came ideas for technology that could capture carbon from the atmosphere to ease the negative impacts of global warming. Klaus Lackner was among the first to propose that approach to climate engineering and then begin designing the technology and systems to make it possible. Today, as a Fulton Schools professor and director of ASU’s Center for Negative Carbon Emissions, Lackner and his team have produced a “mechanical tree” that can effectively remove threatening greenhouse gases. Other scientists and engineers have also proposed and prototyped various methods of atmospheric carbon removal. Their efforts still face economic, governmental and political hurdles to becoming operational at scales large enough to play a big part in reversing climate change.