If CO2 in the atmosphere doubled, global temperatures would climb at most by 3.4 degrees Celsius, far below what the UN has been saying for decades

From Investor's Business Daily. Excerpts:

"A new study published in the prestigious journal Nature finds that all those global warming doomsday scenarios aren't credible. Not that you would ever know based on how little coverage this study is getting.

The study, published on Thursday, finds that if CO2 in the atmosphere doubled, global temperatures would climb at most by 3.4 degrees Celsius. That's far below what the UN has been saying for decades, namely that temperatures would rise as much as 4.5 degrees, and possibly up to 6 degrees.
Basically, the scientists involved in the Nature study found that the planet is less sensitive to changes in CO2 levels than had been previously believed. That means projected temperature increases are too high.

Of course this is just one study, but it supports the contention climate skeptics have been making for years — that the computer models used to predict future warming were exaggerating the impact of CO2, evidenced in part by the fact that the planet hasn't been warming as much as those models say it should.

Why is this important? Because all those horror stories told over the past decades are based on predictions of  temperature increases that are much higher than 3.4 degrees.

A 2008 National Geographic series, to cite just one example, contended that scientists are warning that the global average temperature could increase by as much as 6 degrees Celsius over the next century, "which would cause our world to change radically." Oceans, it said, would become marine wastelands, deserts would expand, catastrophic events would be more common.

The Obama administration's EPA put out a report in 2015 claiming that climate change would triple the number of extremely hot days in the U.S. by 2100, increase air and water pollution, cause $5 trillion in damages for coastal property, and result in tens of thousands of premature deaths.
The EPA assumed a global temperature increase of 5 degrees."

"And don't be surprised if scientists end up revising peak warming down even further. That's been the trend up until now, after all. Back in 1977, the National Academy of Sciences said temperatures would shoot up 6 degrees C by 2050 because of CO2 emissions. In 1985, James Hansen claimed that doubling CO2 levels would boost temperatures up to 5 degrees, and other computer models at the time put the upper bound at 5.5 degrees."

"Even if it's true that 17 of the 18 hottest years have occurred since 2001 — which requires one to assume the government's manipulation of past temperature data has been on the up and up — the relevant question isn't what's happening now, but what is likely to happen going forward.

If the scientific evidence is showing that the harm from CO2 emissions will be far less than feared, we should be celebrating."