Americans harbor misconceptions about two important trends. One concerns global poverty. An overwhelming majority believes it is getting worse and can’t be solved, while the reality of the last several decades tells a dramatically different story. Since the 1980s, the number of people in extreme poverty has dropped by half.

The other is that overpopulation is a looming problem destined to sap the planet’s resources, causing worldwide starvation and collapsing economies. Again, reality tells a different story, which ought to be obvious to even a casual observer.

Life has gotten measurably better in nearly every sense over the last two centuries or more, and that has happened despite a rapid increase in the earth’s population.

The issues are related. Human beings are the earth’s greatest natural resources. As 19th century social thinker John Ruskin put it, “There is no wealth but life. … That country is the richest which nourishes the greatest number of noble and happy human beings.”

Time and again, human innovation, invention and ingenuity have come up with ways to burst through barriers that experts had warned would signal a tipping point to the earth’s carrying capacity.

But while people labor under these two misconceptions, they also may be missing the real population trend that ought to be causing alarm. Birthrates in much of the world have sunk below the roughly 2.1 children per woman that is considered replacement level. Even in the developing world, where birthrates remain high, they are shrinking. As a result, the world is headed for a period in which populations will be graying — a trend that, as a recent report in The Economist made clear — has already begun. That will be followed by a time when the world’s population may begin to shrink.

Circumstances can change, of course. Experts once predicted such a decline and were surprised by the 18-year baby boom that began in 1946, spurred by optimism at the end of World War II. But if the current trend continues, there is every reason to believe the world will begin to struggle through shrinking economies, a decline in innovation and a perpetual condition in which the elderly exist in numbers too large for the young to support.

The 2013 World Population Ageing report by the United Nations concluded that nearly every country in the world is experiencing “population ageing.” This, it said, “results from decreasing mortality, and, most importantly, declining fertility.”

From 1990 to 2013, the share of people 60 and over worldwide has gone from 9.2 percent to 11.7 percent, and the trend continues.

Currently, the world has 841 million people over 60, and the U.N. projects this will grow to more than 2 billion in 2050. By 2047, this age group will exceed the number of children in the world for the first time in recorded history. Significantly, 80 percent of the older population will live in developing countries, according to projections.

Experts differ as to the consequences of this demographic shift. Some believe that older workers will remain in the workforce past 65, providing valuable expertise and institutional knowledge. Others see the inevitable strains on health care, pensions and programs such as Social Security.

Author and Weekly Standard writer Jonathan Last said people won’t notice a drop in the earth’s population until after the last generation with a fertility rate above replacement levels has died. That could be several decades away. Last also uses data to argue that population growth leads to innovation, invention and conservation, and that, conversely, a shrinking population may not enjoy such things.

Older people tend not to be as innovative as the young.

What can the world do about this trend? The best solutions involve government policies that encourage marriage and families. These include tax breaks that encourage large families. Also, government should adopt policies that encourage and support religious freedom.

There is evidence, such as a report from the Barna Group, a research organization in California, that Christians feel a greater responsibility to solve global poverty than nonbelievers. There is reason to believe this extends to believers of other faiths, as well. In addition, believers tend to emphasize family life and have a higher fertility rate than nonbelievers.

The first step, however, is for people to begin to recognize that on a global scale, overpopulation is not nearly the concern that underpopulation will be — and that human ingenuity has been and will continue to be the key to solving a host of ills that once seemed to loom large.