This planet has a hard enough time feeding 7.6 billion mouths. But what happens when the population reaches 9 billion in just a few decades?
To put more pressure on the situation, we're getting bigger and hungrier with each generation, according to a new study from Norwegian scientists.
"It will be harder to feed 9 billion people in 2050 than it would be today," Gibran Vita, a researcher at the Norwegian University of Science and Technology and co-author of the study, explained in a press release.
For the study, researchers compared average adult humans from 1975 and 2014 from 186 countries.
They noted that the average human in 2014 was 14 percent heavier than his 1975 counterpart. He was also 1.3 percent taller and required 6.1 percent more energy than that '70s human.
"An average global adult consumed 2,465 kilocalories per day in 1975," Vita explained. "In 2014, the average adult consumed 2,615 kilocalories."
Not only that, but 2014 humans populations were older — on average, they lived 6.2 percent longer.
So, over 40 years, humans got bigger and hungrier and stuck around longer than before.
Now, assuming there will never be a day that the girth stands still — we'll continue growing and eating and getting ever older — what can we expect over the next few decades?
Our population is widely forecast to hit the 9 billion mark by 2050 before leveling off somewhat, although some scientists suggest we'll rocket to 12 billion by the end of this century.
In any case, there are already plenty of scientific models that forecast how we'll sustain these fresh, hungry mouths.
But until now, we've assumed those mouths will eat at a fairly standardized rate: every human requires a fixed amount of energy from food.
The new research suggests those energy levels are anything but fixed. Bigger humans will need a bigger slice of the pie. And they'll be nibbling away during their much longer lifespans.
In another words, we need to adjust food supply models, which are already bordering on dire, for the future.
"Previous studies haven't taken the increased demands of larger individuals and aged societies into account when calculating the future food needs of a growing population," study co-author Vásquez noted.
If the new research holds true, and we're really getting hungrier across the board, than those older models will need significant adjustment.
"These assumptions can lead to errors in assessing how much food we'll actually need to meet future demand," Vásquez says.
Brace yourself, Mother Earth. You've got a lot more giving to do.