SEATTLE — Close your eyes and imagine the world nearly three decades from now in 2050. What do you picture? Flying cars zooming through the skies? Robot assistants in every home? While the future may hold many technological wonders, there’s still one critical question to answer: what will the overall health of the human population look like? Luckily, a new study has some good news, finding that the average person will also be living longer in the future.

A comprehensive study published in The Lancet used cutting-edge modeling techniques to forecast disease burden, life expectancy, and population shifts for over 200 countries through 2050. It’s a crystal ball gaze at humanity’s health on a global scale.

So what did they find? Let’s start with the good news. Researchers from the Global Burden of Disease Study, an international consortium of experts, projects that average life expectancy will continue to climb in the coming decades, albeit at a slower pace than we’ve seen in the past. Babies born in 2050 can expect to live to around 80 on average if current trends continue. That’s up from a global average life expectancy of about 74 today. The greatest gains are expected in regions currently facing the highest rates of premature death and disability, places like sub-Saharan Africa.

While longer lifespans are certainly something to celebrate, the researchers caution that those extra years won’t necessarily be spent in good health. In fact, the proportion of life spent living with some kind of illness or disability is forecasted to grow. Across all regions, people will be living more years with chronic diseases and injuries than in the past.

What’s driving this concerning trend? In a word, aging. As lifespans extend and fertility rates decline, the world population will get much grayer in the coming decades. The study predicts that by 2050, over 12 percent of people globally will be over the age of 70, nearly double the proportion today. While advancing age is a key risk factor for many chronic diseases, population aging alone doesn’t tell the whole story.

The researchers also point to major ongoing shifts in the types of diseases and injuries that impact human health. While the 20th century was defined by incredible progress against infectious killers like malaria and diarrheal diseases that strike in childhood, the coming decades will be increasingly dominated by non-communicable diseases more commonly associated with older age – things like heart disease, diabetes, and dementia.

Globally, the leading causes of premature death and disability in 2050 are forecasted to be ischemic heart disease, stroke, diabetes, and chronic lung diseases, with common infections continuing to fall in the rankings. This changing disease landscape reflects not only an aging population but also shifting lifestyles and environments, with factors like obesity, unhealthy diets, and air pollution taking an increasing toll.

Of course, these are just projections based on current trends, not a definitive vision of our fate. The researchers stress that the future of health is still very much in human hands. To illustrate this, they modeled some alternative scenarios, imagining what 2050 might look like if we made dramatic progress in key areas.

For example, in an optimistic scenario where exposure to environmental risks like unsafe water and household air pollution is eliminated by 2050, over 57 million early deaths could be prevented compared to the “business as usual” forecast. Likewise, dramatically reducing behavioral risks like smoking and obesity could avert over 400 million cumulative early deaths. A scenario of “moon shot” improvements in childhood nutrition and vaccine coverage showed more modest but still notable impacts.

Achieving changes of this magnitude is certainly a tall order that would require major societal shifts and investments. However, the modeling suggests that changing our trajectory is possible with coordinated, ambitious efforts. In contrast, the researchers caution that if efforts to continue recent progress against infectious diseases were to falter, the forecasts of improved health would quickly fall apart, especially in the most vulnerable populations.

So, where does this leave the world? The study authors say there’s both promise and peril on the horizon.

The world has made tremendous strides in human health and longevity, but we can’t rest on those laurels. Humanity in 2050 may enjoy longer lifespans on average but also more years spent coping with chronic conditions if current trends continue without change.

Changing that trajectory isn’t impossible, but it will take serious work. At the individual level, that means doubling down on the age-old pillars of health – things like eating well, staying active, avoiding smoking, and keeping up with preventive care. At the societal level, it demands policies that make healthy choices accessible and appealing for all, coupled with tireless efforts to develop new ways to predict, prevent, and treat disease.

The journey to 2050 and beyond will no doubt hold many surprises, but one thing is clear: the future of human health isn’t fixed.

StudyFinds Editor-in-Chief Steve Fink contributed to this report.