The researchers say that emissions are the largest contributor to future climate change and a strong indicator of potential future warming.

BBC: Carbon emissions are 'too high' to curb climate change

The number 400 has been anticipated by climate scientists and environmental activists for years as a notable indicator, in part because it's a round number not because any changes in man-made global warming happen by reaching it.

NPR: Greenhouse Gas Milestone; CO2 Levels Set Record

These functions include a charge status indicator and the ability to control the vehicle's new auxiliary climate control option, which enables vehicle preheating or cooling via the Porsche Car Connect app.

ENGADGET: Porsche Panamera S E-Hybrid plug-in model brings 416 guilt-free horsepower