Unless the United States solves the problem of man-made climate change in the next 12 years—or maybe 10 years—it's game-over for humanity. At least that's what viewers for the two CNN Democratic presidential debates might take away from urgent declarations made by various candidates. Let's go the transcripts.

In the first debate, held Tuesday night in Detroit, former Texas Congressman Beto O'Rourke declared, "I've listened to the scientists on this, and they're very clear. We don't have more than 10 years to get this right." Sen. Elizabeth Warren (MA) warned that the "climate crisis is the existential crisis for our world. It puts every living thing on this planet at risk."

But wait, there was more! "By 2030, we will have passed the point of no return on climate," claimed Montana Gov. Steve Bullock. South Bend, Indiana Mayor Pete Buttigieg said that "science tells us we have 12 years before we reach the horizon of catastrophe when it comes to our climate."

The candidates in the second Democratic debate, held Wednesday night in Detroit, were a bit more circumspect with regard to setting drop-dead climate deadlines on stage.

Sen. Kamala Harris (D–Calif.) stated that "we must have and adopt a Green New Deal. On day one as president…I would re-enter us in the Paris agreement. And put in place [policies] so we would be carbon neutral by 2030."

Washington Gov. Jay Inslee, who has made addressing climate change the center of his campaign, asserted that "the science tells us we have to get off coal in 10 years. Your [Biden's] plan does not do that. We have to have [sic] off of fossil fuels in our electrical grid in 15."

During the debate, Rep. Tulsi Gabbard (D–Hawaii) observed that "long before there was ever a Green New Deal, I introduced the most ambitious climate change legislation ever in Congress called the Off Fossil Fuels Act." That act says 80 percent of all electricity, new vehicles, and train lines must be fueled by no-carbon sources of energy by 2027, rising to 100 percent by 2035.

While these candidates did not set a climate doomsday deadline during the debate, Sen. Kristen Gillibrand (D–N.Y.) did declare that "the greatest threat to humanity is global climate change," and Sen. Cory Booker (D–N.J.) stated that "everything must be sublimated to the challenge and the crisis that is existential, which is dealing with the climate threat."

So, are these Democratic presidential hopefuls right that humanity and the planet are really doomed if the U.S. doesn't stop using fossil fuels and emitting carbon dioxide by 2030? Actually, they all seem to have over-interpreted the Global Warming of 1.5 °C report issued last year by the U.N.'s Intergovernmental Panel on Climate Change.

That report concluded that in order to keep the planet from warming more than 1.5°C over the pre-industrial average temperature by 2100 that humanity must cut greenhouse gas emissions—chiefly carbon dioxide emitted by the burning of fossil fuels—in half by 2030, and reach net-zero emissions by 2050. Citing a couple of irritated climate scientists, the fact-checkers over at the Washington Post noted that the report definitely did not find that going over the 1.5°C threshold is the end of the world.

For example, Myles Allen, one of the lead authors of the IPCC report, wrote in April, "Please stop saying something globally bad is going to happen in 2030. Bad stuff is already happening and every half a degree of warming matters, but the IPCC does not draw a 'planetary boundary' at 1.5°C beyond which lie climate dragons."

Kristie L. Ebi, director of the Center for Health and the Global Environment at the University of Washington, told the Associated Press that that "the report never said we only have 12 years left."

When the IPCC report first came out, I noted:

The report asserts that if no policies aimed specifically at reducing carbon dioxide emissions are adopted, then average global temperature is projected to rise by 3.66°C by 2100, resulting in global GDP loss of 2.6 percent from what it would otherwise have been. Comparatively speaking, in the 2°C and 1.5°C scenarios, global GDP would only be reduced by 0.5 percent or 0.3 percent respectively. Concretely, the global GDP of $80 trillion, growing at 3 percent annually, would rise to $903 trillion by 2100. A 2.6 percent reduction means that it would only be $880 trillion by 2100. A 0.3 percent decrease implies a loss of $2.7 trillion resulting in a global GDP of $900 trillion. Note that the IPCC is recommending that the world spend between now and 2035 more than $45 trillion in order to endow $2.7 trillion more in annual income on people living three generations hence. Assuming the worst case loss of 2.6 percent of GDP in world with a population of 10 billion that would mean that they would have to scrape by on an average income of just $88,000 per year (the average global GDP per capita now is $10,500.)

Living in the warmer world of 2100 on incomes that are around eight times higher than the current average is not the end of civilization.

During the debate, tech entrepreneur Andrew Yang had an interestingly different take on the challenges posed by man-made climate change. He noted that the U.S. is responsible for only about 15 percent of global emissions, so "even if we were to curb our emissions dramatically, the earth is still going to get warmer." He added, "This is going to be a tough truth, but we are too late. We are 10 years too late. We need to do everything we can to start moving the climate in the right direction, but we also need to start moving our people to higher ground."

One interpretation is that "higher ground" in Yang's lexicon is a metaphor for making it possible for folks to adapt to whatever climate change is coming. (Of course, it more concretely suggests more wealth will make it possible for folks to withdraw from rising seas and flooding rivers.) Yang continued that the best way to get people to higher ground is "to put economic resources into your hands so you can protect yourself and your families." While Yang is most likely referencing his universal basic income plan, his insight is correct that adopting policies that speed up innovation and wealth creation will enable people to adapt to and even thrive in a warmer world.

Climate change is a problem, but, contrary to the dark apprehensions of many Democratic Party presidential hopefuls, the end of the world is not scheduled for 2030.