According to the Union Of Concerned Scientists, global warming emissions from electric cars (mid-sized EV with about 84 miles EPA range - think Nissan LEAF) are 50+% lower than gasoline cars over their lifetime (from manufacturing, through driving and on to disposal).
With a growing ratio of renewable energy sources, emissions from electric cars will be even lower in the future.
Electric Cars & Global Warming Emissions
"Everyone knows electric cars are cleaner than gasoline vehicles—but just how much cleaner? This video explores the global warming emissions of EVs on a lifecycle basis, from the manufacturing of their batteries to their ultimate disposal or reuse."
We confine ourselves this time to two major graphs with EV's GWP calculations for different electricity suppliers and comparison to ICE:
Electric Vehicle Global Warming Pollution Ratings and Gasoline Vehicle Emissions Equivalents by Electricity Grid Region
Life Cycle Global Warming Emissions from the Manufacturing and Operation of Gasoline and Battery-Electric Vehicles