There's no single silver bullet that will reduce the energy consumption and emissions from the 80 million new road vehicles sold globally each year.
Instead, thousands of individual efforts to improve the efficiency of powertrains, reduce vehicle weight, cut wind resistance, and all the rest come into play.
But alternative powertrains will likely play the biggest role, with many varieties of electrification—hybrids, plug-in electric cars, and hydrogen fuel cells—vying in different applications.
We queried our Twitter followers about how they ranked these different possibilities, effectively asking them to pick winners and losers.
Specifically, we asked which of four different electrified technologies would matter least in 2025.
The results weren't quite what we expected.
Which green-car technology will matter least in 2025?— Green Car Reports (@GreenCarReports) December 6, 2016
We're not all that surprised that almost half the respondents (47 percent) said hydrogen fuel cells would be least significant in 2025.
Vehicles powered by hydrogen fuel cells face many challenges, most notably the high cost of establishing a pervasive network of hydrogen fueling stations.
But conventional hybrids and battery-electric cars came in surprisingly close together for second and third place, at 26 percent and 22 percent respectively.
Given the strong enthusiasm among large numbers of our readers for all-electric vehicles, we hadn't expected battery-electric cars to rate that high as least important technology.
2017 Toyota Prius Prime and 2017 Chevrolet Volt with Green Car Reports editor John Voelcker
And just 5 percent chose plug-in hybrids as the technology that will matter least in 2025, by far the lowest proportion of any of the four.
As always, it's not clear that our Twitter followers correspond entirely to our readers—but the results are still food for thought.
Perhaps they indicate continuing skepticism that battery-electric vehicles can really handle the full range of duties we expect our gasoline vehicles to perform.
Those include predictable operations in very hot and cold weather, transporting a variety of goods and supplies from big-box stores, and occasionally taking entire families, pets, and luggage on long road trips.
We strongly suspect that many carmakers have performed far more sophisticated versions of the same kind of research as they struggle to divine what buyers are open to and how they view alternative powertrains.
Sadly, we also suspect we'll never see the bulk of that data.