Civilization may have reached its peak — humans might not get any healthier or longer-lived than they are right now. CC0 Creative Commons

Humans won’t get any better than they are right now, scientists say. In fact, we can expect to become less healthy and live shorter lives in the future.

Although people have made great biological strides in recent centuries, including increasing lifespans, there has been a great slowdown of those improvements, a group of experts wrote in an article for the journal Frontiers in Physiology. They say that’s because our species has reached its peak and will only trend downward from here. And climate change may help drive that dive.

The team analyzed genetic and environmental factors to investigate the biological limits of humans, in the realm of longevity, height and physical abilities like performance in sports. In terms of lifespan, for example, medical and technological advancements have pushed the average life expectancy close to 100 and the maximum a couple of decades beyond that. But how much further could we reasonably go?

“The human body, as in any living species, is a finite organism, with structural … and functional boundaries at every level of organization,” the article says.

Even though scientific progress continues, the authors wrote, we do not see any more large shifts in our lifespans, heights or sports achievements; there are no significant changes in the maximum life expectancy or in sports records.

“This suggests that modern societies have allowed our species to reach its limits,” according to the article. “We are the first generation to become aware of these limitations.”

There may be, however, more people reaching the current biological limits as time goes on.

The scientists say our focus should be on avoiding backsliding to become shorter and shorter-lived. But that could be a challenge, since they predict that man-made environmental problems like climate change will work against us.

“This will be one of the biggest challenges of this century as the added pressure from anthropogenic activities will be responsible for damaging effects on human health and the environment,” researcher Jean-François Toussaint, from France’s Paris Descartes University, said in a report from journal Frontiers. “The current declines in human capacities we can see today are a sign that environmental changes, including climate, are already contributing to the increasing constraints we now have to consider. … Now that we know the limits of the human species, this can act as a clear goal for nations to ensure that human capacities reach their highest possible values for most of the population.”