Above all, hydrocarbon consumption is just big: Last year we burned oil, gas, and coal with an energy equivalent of almost 12 billion tons of oil. Like The Bridge, it’s hard to get your head around the scale.

But in a transition, scale only tells you where you are; marginal growth points to where you’re going. Rather than focus on the mountain, get a feel for the gradient of travel.

Harry Benham, an oil industry veteran turned consultant, presents this as a math problem. Primary energy consumption grows at about 1% to 2% a year, and that rate has trended downward, more or less, since the 1960s. That’s linear growth, meaning the world’s sources of energy, no matter how big or small, must fight for a slice of that shrinking sliver of extra demand over time. Wind and solar power, while small, are expanding at a ferocious clip: 23% a year, compounded, over the past decade. Which means they grab a bigger share. Having generated less than 2% of the world’s electricity a decade ago, wind and solar will likely surpass nuclear power this year or next.

This collision course is driven by cost. Less than a decade ago, shale frackers needed maybe $100 a barrel to break even. Now some need less than $50. Impressive, but the all-in cost of solar power has dropped 85% since 2010, and BloombergNEF forecasts an additional 63% drop through 2050. In two-thirds of the world, up from 1% five years ago, new solar and wind projects undercut new plants that use either coal or natural gas.

If you think oil is safe in its internal-combustion fortress, consider that electric models accounted for all the growth in passenger-vehicle sales last year and are forecast to do the same this year. Again, it’s scale vs. growth. Sales of traditional gas guzzlers, while still 80 million-odd strong, have declined. And investors, technology talent, and research and development budgets tend to start backing away from little changed or shrinking markets, no matter how big they are. Energy stocks are out of favor not because they’re no longer dominant; they clearly are. But mortality has begun to creep into risk premiums.

Despite the falling costs and growing market share of renewable energies, they still lack the killer app: a price on carbon emissions that would expose the frequently hidden costs of fossil fuels. Conventional wisdom holds that Americans, especially, wouldn’t stand for that.

But aside from President Trump professing ardor for “beautiful” coal, few people love hydrocarbons—when was the last time you fist-pumped at the prospect of a trip to the gas station? Most folks don’t even care about energy. What they love is what it provides: light for dark streets, cool offices on hot days, and, of course, the ability to travel. These hallmarks of modernity—the ends, not the means—persuade us to tolerate the drawbacks.

One is pollution. In the past, when society reached tipping points on industrial nasties such as leaded gasoline or smog, government acted to curb them. Carbon emissions, invisible and with a slow, diffuse impact, are of a different order. Even here, however, sentiment is shifting, and that gradient of public tolerance is steepening.

For example, oil majors’ relatively recent touting of renewable energy investments may strike you as “greenwashing.” The point is that they’ve acknowledged that man-made carbon emissions cause climate change. That particular cat won’t go back in the bag.

It’s also easy to dismiss Pope Francis’ recent convening of oil bosses in the Vatican as political theater. But as Kevin Book of Washington-based ClearView Energy Partners says, the church epitomizes conservatism and tradition: “The activists are already persuaded about climate change, and now the Vatican is, too.” In a pleasing irony, the pope pushed the case for climate science in the same building where Galileo was tried by the church for his own bit of scientific insight.