Among the greatest challenges humankind has faced throughout its history, feeding the world’s hungry ranks at or near the very top of the list. And with the world’s population expected to top nine billion between 2050 and 2100, this issue will surely become even more important in the coming decades.

However, what many people may not realize is that the carbon dioxide humans have been pumping into the air since the middle of the 20th century has enriched plant growth, thereby contributing to record crop yields, which has helped to bring about the largest decline in hunger, starvation, and malnutrition in human history.

Most of the world’s plant life arose during times when carbon-dioxide levels were much higher than they are today. Over time, the amount of carbon dioxide in the atmosphere slowly declined, to the extent that during the most recent ice age, atmospheric carbon-dioxide levels fell to dangerously low levels -- just 180 parts per million (ppm). Plants begin to die when carbon dioxide reaches 150 ppm, because they are unable to use sunlight to photosynthesize food from carbon dioxide and water. After humans emerged from the previous ice age, carbon-dioxide levels rose to approximately 280 ppm, still far below the levels existing when plant life began to colonize the land.

Let’s be clear: If plants die, humans and almost all other living beings on Earth will perish as well, so, historically speaking, higher carbon-dioxide levels are positive and associated with more life on Earth.

The addition of approximately 120 ppm carbon dioxide to the atmosphere by humans -- through the burning of fossil fuels, slash-and-burn agriculture, and various other actions -- is making plants grow stronger, more quickly and abundantly, and improving the efficiency with which they use water. (Under higher carbon-dioxide conditions, plants lose less water through their stoma during transpiration.)

Since the widespread development and use of fossil fuels, world poverty and hunger have declined precipitously. Despite adding 3.2 billion people to the planet since 1968, poverty and hunger have fallen at a faster rate than at any time in human history.

Contrary to the predictions made by 1968 Malthusian environmentalists such as Paul Ehrlich, who said in his woefully mistaken 1968 jeremiad The Population Bomb, “The battle to feed all of humanity is over. In the 1970s hundreds of millions of people will starve to death in spite of any crash programs embarked upon now,” more people are better fed today than ever before.

Forty-four percent of the world’s population lived in absolute poverty in 1981. Since then, the share of people living in extreme poverty fell below 10 percent in 2015. And although 700 million people worldwide still suffer from persistent hunger, according to the United Nations, hunger has declined by two billion people since 1990. Additionally, research shows there is now 17 percent more food available per person than there was 30 years ago.

This food abundance arose even as the amount of land devoted to agriculture declined over the same period, with former farm fields reclaimed by forests and pastures. How is this possible? Mostly because of two factors: (1) the large-scale application and widespread use of modern technologies related to agriculture, many of which dependent on carbon dioxide, and (2) increased carbon-dioxide levels in the atmosphere.

Farmers have replaced oxen and horses with fossil-fuel powered tractors and manure with high inputs of chemical fertilizers and pesticides, which require fossil-fuels in their manufacture or as components. Agronomists using traditional cross-breeding techniques and genetic engineering have developed new crop varieties that are hardier, disease-resistant, pest-resistant, vitamin-fortified, and that use water more efficiently.

Increasing amounts of carbon dioxide in the atmosphere have also helped crops grow. Humans’ carbon-dioxide emissions have greened Earth, transforming some former desert regions into verdant oases of greenery, and contributed to record crop yields. World-Grain.com reports in 2016, world cereal production broke records for the third straight year, exceeding the previous record yield by 1.2 percent, recorded in 2015, and exceeding the record yield recorded in 2014 by 1.5 percent.

Contrary to the many dire predictions made by Ehrlich in 1968 and others since, humans have moved much closer to the truth captured by a New York Times headline from May 2016: “Is the Era of Great Famines Over?” The answer appears to be “yes.” Political decisions and war, not food scarcity, is now usually responsible when populations face starvation or malnutrition.

We should praise carbon dioxide for helping to feed the world, not demonize it. Carbon dioxide is not a pollutant, as so many erroneously or misleadingly suggest; it’s entirely natural and vital to all life on Earth.

It’s true you can have too much of a good thing, but when it comes to carbon dioxide, we are not even close to being there yet.

H. Sterling Burnett, Ph.D. (hburnett@heartland.org) is a research fellow on energy and the environment at The Heartland Institute, a nonpartisan, nonprofit research center headquartered in Arlington Heights, Illinois.