Presuming China sticks to its statement that it will ban sales of new vehicles with combustion engines in some future year, the auto industry is facing a very different future than it was a year ago.

Similar bans from Norway, The Netherlands, France, and the U.K. all represented smaller markets, but China is by far the world's largest single source of new-vehicle sales.

Last year roughly 30 million vehicles were sold there, close to double the U.S. total of 17.5 million.

DON'T MISS: China developing timetable to end sales, production of gasoline cars

The current U.S. government appears to be in the process of rolling back emission standards enacted in 2012 for model years 2022 through 2025, but European countries are tightening theirs.

But let's assume that the attitudes of the Trump Administration, whose top administrators have frequently denied accepted climate science, are a temporary aberration.

We were curious to see when our Twitter followers thought the U.S. might take a step similar to that of China, and ban all sales of new vehicles with gasoline or diesel engines.

The responses to our poll did not indicate a great faith in the ability of the U.S. to lead the world in reducing vehicular emissions of carbon dioxide.

More than a third of respondents (38 percent) said such a ban would happen only in 2050 or later.

CHECK OUT: "Death of the internal combustion engine" is now a thing

Almost another third, or 29 percent, said that kind of ban would simply never happen. Ever.

Taken together, that means two-thirds of our poll audience believes more than three decades at minimum will have to pass for the U.S. to take such an action.

BYD e6 electric taxi in service in Shenzhen, China

BYD e6 electric taxi in service in Shenzhen, China

Another quarter of respondents, or 25 percent, thought such a ban could happen by 2035, but a mere 8 percent chose the 2025 option—the year chosen by Norway, but now only eight years away.

That last option isn't surprising, but given the annual 7-percent reduction in the cost of lithium-ion battery cells, it's conceivable that by 2035, 200-mile battery-electric cars will be cheaper than their counterparts with gasoline engines.

Still, change often comes more suddenly than people predict—driven by the pace of technological change.

READ THIS: CA mulls ban on new cars with engines, joining China in climate action

Whether the politics will catch up to the technology, however, remains a more open question.

As always, please note that our Twitter polls are far from scientifically valid, due to small sample size and self-selection by those who choose to participate.

Green Car Reports respectfully reminds its readers that the scientific validity of climate change is not a topic for debate in our comments. We ask that any comments by climate-change denialists be flagged for moderation. Thank you in advance for helping us keep our comments on topic, civil, respectful, family-friendly, and fact-based.

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