The world as we know it, some believe, needs fossil fuel to grow.

Not so, according to a new study.

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Fossil fuels aren't the key to longer life expectancy

"Global demand for energy is rising, driven by growing population with rising living standards," reads the Shell website. A recently-deleted BP ad said, "the world needs progress, seeking new possibilities everywhere so we can keep powering dreams and ambitions." In other words, the key to people of the world living long, more prosperous lives is access to energy.

However, a study — forthcoming in the journal Environmental Research Letters — came to a starkly different conclusion. After examining the relationship between life expectancy and fossil fuel use across 70 countries from the year 1971 to 2014, the researchers found that the increase in energy consumption was not the primary reason countries saw increased life expectancy. Although energy and energy consumption were correlated with life expectancy — an increase of 14 years over the 43-year period — the increase in energy use only accounted for roughly one-quarter of that increase: roughly four of those 14 years.

"The easiest way to explain this is a thought experiment: given the relationships we measure from our data, can we measure how much life expectancy would have increased if only fossil fuel emissions had increased? And can we measure how much life expectancy would have increased without any increase in fossil fuel emissions? The total of these two add up to the total change in life expectancy," said lead author of the study Julia K. Steinberger to Earther, via email.

Energy consumption makes money, not well-being

However, the researchers found that increased energy consumption was associated with a 90% increase in GDP — the economic meter usually used as a basis for assessing a country's well-being, and ultimately the well-being of its residents. Academics have debated whether increasing GDP is possible while also reducing carbon emissions for a long time.

For their part, the authors argue that GDP is an intrinsically flawed meter for residents' well-being because, just because it does assess the economic standing of a nation, doesn't mean it speaks to how that wealth is (or isn't) distributed, let alone how long and well residents will live. If policymakers mean what they say when they claim to care about improving people's lives while lowering greenhouse gas emissions, these findings are good for everybody.

"Our results directly counter the claims by fossil fuel companies that their products are necessary for well-being," said the authors in a statement. "Reducing emissions and primary energy use, while maintaining or enhancing the health of populations, should be possible."

Economic growth, argue the authors, shouldn't be the national goal. Instead, the authors suggest people can have perfectly good lives and climb out of poverty without fossil fuels or perpetual growth economics.

Notably, even though a country's total energy usage and greenhouse gas emissions weren't to blame for a sizable amount of the increase in life expectancy seen between 1971 and 2014, the increase in residential electricity — like the ability to switch on lights and cooking with gas from fossil fuels — comprised a 60% increase in life expectancy.

Editor's Note: An earlier version of this article suggested that the study by Julia K. Steinberger and colleagues observed the relation (or lack of one) between energy use and "happiness," or the ability to live long, "happy" lives. This is a mischaracterization; the study did not involve happiness indicators. Instances of "happiness" and "happy" that occurred in the abstract summary and text of this article have since been changed to reflect this. IE regrets these errors.