‘…Mark Z. Jacobson, a Stanford professor of civil and environmental engineering, was more optimistic. His research influenced a California law last year requiring the state to use 100 percent carbon-free energy by 2045. Mr. Jacobson said that 80 percent of the Green New Deal’s target of net-zero greenhouse emissions across the economy could be achieved by 2030, and 100 percent between 2040 and 2050.’