Let’s not allow Earth Day to pass without a mention. Earth Day was April 22 and it was marked by the signing of the Paris Climate Accords by the United States and other countries.

“Today is Earth Day – the last one I’ll celebrate as president,” Obama said on Friday. “Looking back over the past seven years, I’m hopeful that the work we’ve done will allow my daughters and all of our children to inherit a cleaner, healthier and safer planet. But I know there is still work to do. That’s why, today, the United States will join about 170 other countries in signing the Paris Agreement, a historic deal to reduce carbon emissions across the globe.”

His statement came with a dire warning: “The impact of climate change is real. … So we’ve got to do something about it before it’s too late.”

But let’s look at the history of those dire Earth Day warnings. History shows they’ve always been wrong.

In 1970, for example, the year Earth Day was first celebrated, one scientist predicted that all civilization would end within three decades.

As the Daily Caller reports, “Harvard biologist Dr. George Wald warned shortly before the first Earth Day in 1970 that civilization would soon end ‘unless immediate action is taken against problems facing mankind.’ Three years before his projection, Wald was awarded the Nobel Prize for Physiology or Medicine.”

In fact, civilization seems to still be standing.

But 1970 was a banner year for bad predictions. Paul Ehrlich, author of “The Population Bomb,” warned that mass starvation was just around the corner. He predicted that within 10 years of that date, 100 to 200 million people would be starving to death.

“His dire predictions failed to materialize as the number of people living in poverty has significantly declined and the amount of food per person has steadily increased, despite population growth,” the Daily Caller noted. “The world’s Gross Domestic Product per person has immeasurably increased despite increases in population.”

He wasn’t alone in his belief of mass famine within decades.

“Demographers agree almost unanimously on the following grim timetable: by 1975, widespread famines will begin in India; these will spread by 1990 to include all of India, Pakistan, China and the Near East, Africa. By the year 2000, or conceivably sooner, South and Central America will exist under famine conditions,” wrote Peter Gunter, a professor at North Texas State University.” By the year 2000, the entire world, with the exception of Western Europe, North America and Australia, will be in famine.”

India is now the world’s seventh-largest food exporter.

Also in 1970, Life magazine predicted, “in a decade, urban dwellers will have to wear gas masks to survive air pollution … by 1985 air pollution will have reduced the amount of sunlight reaching Earth by one half.”

But according to the World Health Organization, air quality is improving worldwide, with some notable exceptions (mostly in China).

What’s even more clear than urban air lately is this – those predictions were scaremongering.