A 16-year-old Swedish high school student, Greta Thunberg, has become the new face of the climate change movement. She has more than a million followers on Twitter, where she has described herself as a “16-year-old climate activist with Asperger.” Late last summer she began skipping school on Fridays to travel to Sweden’s Parliament, the Riksdag, to lobby lawmakers with flyers, often containing what the New York Times described as “crude language,” that these same lawmakers she hoped to persuade were “ruining her future.”

Her blunt talk and fresh face attracted a following, not just on Twitter, but around the world. Her habit of skipping school became a symbolic gesture, and on Monday she organized a “climate change skip day” in which hundreds of thousands participated. She was also a featured speaker at a United Nations event on climate change.

As much as I admire her boldness and willingness to enter the arena, I cannot offer more than faint praise to this child. (I do not use “child” in a patronizing or condescending manner: that’s what she is careful to call herself when she speaks to heads of state and other potentates.) In fact, because she is a child, the climate change movement has cleverly managed to change the conversation from facts — where they have been unpersuasive – to emotions, where they hope for better success. By putting their often-specious arguments in the mouth of a 16-year-old with pig-tails, they have made them difficult to criticize.

That’s why New York Times columnist Christopher Caldwell calls her activism “undemocratic.”

Greta Thunberg is just the latest in a long line of doomsday prophets. David Wallace-Wells’ book “Uninhabitable Earth” (which I reviewed here) is a member of this tribe. Both of them are taking advantage of the built-in advantages of doomsday prophesies. Prophets of disaster win either way. If their prophesies come true, the prophets can say, “I told you so.” If they don’t come true, they can say “not yet” or “thank God you listened!”

But it is important to consider the doomsday prophesies of times past as we evaluate the activism of Thunberg and Wallace-Wells. For example, Paul Ehrlich wrote “The Population Bomb” in 1968, saying a global population explosion would result in mass starvation and food wars by the 1970s. Not only did such crises not come to pass, but today many countries worry about depopulation.

Even we Christians are not immune from the disease of doomsday prophesies. In 1991, Larry Burkett wrote about “The Coming Economic Earthquake,” but the 1990s ended up being one of the greatest periods of economic expansion in global history. In the late 1990s, Michael Hyatt’s “The Millennium Bug” warned about the Y2K computer problem. He encouraged people to stockpile food and buy gas powered generators in case the power grid went down. The power grid survived into the new millennium.

We can look back on doomsday prophets like Burkett and Hyatt with a certain wry humor. They were wrong, but they did no real harm.

Sometimes, though, doomsday prophets wreak great havoc.

Rachel Carson’s “Silent Spring” warned us of the dangers of the insecticide DDT. Her book motivated major policy changes. Subsequent scientific study discovered that DDT was safe when properly used, and highly effective. But many countries banned DDT because of “Silent Spring.” The result? The greatest killer of the 20th century was not war or genocide, but the lowly mosquito.

Rachel Carson’s flawed doomsday predictions likely contributed to the deaths of 100 million people. Today, the direct costs of treatment of the 250 million people who suffer from this preventable disease exceeds $12 billion per year. Other economic losses, including the loss of productivity of those afflicted, are likely many times that number.

In short, flawed doomsday predictions are often not innocent or innocuous. They can be deceitful and damaging.

Science, at its best, is a search for the truth. It should also teach us to be skeptical of our own assumptions and humble about our own conclusions. Science teaches us to look closely at the world and describes what we see with as much precision as possible, but not to assert as fact that which should remain hypothesis.

Greta Thunberg is a teenager. Her worldview is still developing. She has proven adept at whipping those who agree with her into a frenzy. However, democracy requires persuading the unconvinced, protecting and providing a voice for those with minority views, and crafting policies that do not have unintended consequences more damaging than the problems they hope to solve.

One hopes that such climate change doomsday prophets such as David Wallace-Wells and Greta Thunberg might learn from Paul Ehrlich himself, who lived long enough to see the vast majority of the scenarios he laid out in “The Population Bomb” fail to come to pass.

In 2009, he wrote: “In honesty, the scenarios were way off, especially in their timing.” His conclusion? “We underestimated the resilience of the world system.” But because too many policy makers listened to Ehrlich in the 1960s and 70s, the world now faces a global demographic crisis that will likely cause tremendous economic hardship in the decades ahead, as the world struggles to create prosperity in an era of depopulation.

So, God bless Greta Thunberg. I hope she is an inspiration to many young people to get involved in the important conversations of our day.

But when it comes to policy-making, we should also pay attention to the adults in the room.