The political leaders coming from around the world for California Gov. Jerry Brown's climate action summit recently grappled with a lot of urgent deadlines to drive down emissions, but one date is especially exasperating.

It is 2035 — the year advocates aim to kill off production of gasoline and diesel powered vehicles.

Keeping global warming to levels society can tolerate could hinge on meeting that target. But even clean technology capital California has no clear path for getting there.

The question of whether drivers should be gently persuaded or forced out of their internal combustion engine cars and trucks over the next 17 years will weigh heavily on the landmark summit, which runs from Wednesday through Friday in San Francisco.

States, cities and companies will try to chart a course to carry the country and the world toward meeting the goals in the 2015 Paris agreement on climate change that President Donald Trump has disavowed.

Read the full article about the 2035 deadline to eliminate gas and diesel vehicles by Evan Halper at Governing Magazine.