The full dimensions of the wave over the next four or five years, including its impact on the environment and climate change, are hard to predict, in part because they will depend on the policies adopted by many governments. But as several American multibillion-dollar export terminals come on line, few doubt that the influence of more gas, as the cleanest burning fossil fuel, will be consequential for powerful and poor countries alike.

Mexico Could Be a Model

Experts point to Mexico as an example of how transformative gas can be in a matter of only a few years. As the American shale boom accelerated, producing more gas than its northern neighbor could consume, Mexico decided to import as much cheap gas as possible. Mexico replaced its dirtier burning coal and petroleum products, and now more than a quarter of the country’s electricity is powered by American gas.

Four additional cross-border pipelines are to be completed over the next two years, and many more are in the planning phase. The gas imports have improved air quality, helped Mexico reach goals to reduce its carbon footprint to meet Paris climate agreement targets and freed capital to invest in more exploration and production of oil, which is more valuable on world markets.

Because Mexico has a border close to Texas oil and gas fields, pipelines have made the transformation relatively easy. Exporting and importing liquefied gas is more complicated. Gas is expensive to ship overseas because it must be cooled to minus 260 degrees, condensing it to what is called liquefied natural gas, or L.N.G., to be shipped in giant tankers. The importing country then has to turn the liquid back into gas so it can be transported by pipelines. But even though liquefied gas is usually more expensive than piped gas or even coal, demand and supplies are growing fast.

“This bulge of L.N.G. is going to completely upset the apple cart of world energy politics and the global competition of fuels that is still hard for people to comprehend,” said Amy Myers Jaffe, an energy security expert at the Council on Foreign Relations. “Russia will be the loser. We can already see their leverage on the gas market in Europe and the leverage they are trying to create over China dissipating.”