It's Official: There's Only 1-In-A-Million Chance Climate Change Is Not Caused By Humans


Katy Evans

Katy is Managing Editor at IFLScience where she oversees editorial content from News articles to Features, and even occasionally writes some.

Managing Editor


Yep, it's us. Tatiana Grozetskaya/Shutterstock

A new analysis of 40 years’ worth of satellite data has shown we are as close to certain as we can be that global climate change is actively being caused by humans. No doubt some of you will read this and say, almost certain eh? Yes. The “gold standard” level of certainty in scientific evidence has officially been reached.

This “gold standard” is not thrown around lightly. It means evidence has reached a "five sigma" level of certainty – something particle physicists use to determine confidence in their findings, for example, the discovery of the Higgs boson in 2012. Here it means there is a 1-in-a-million chance that ongoing climate change is being caused by anything other than humans, or that we’re 99.99 percent sure it’s us.


The planet is heating up, and natural disasters and extreme weather events are becoming more intense and occurring more frequently because humans burn fossil fuels and cut down trees that absorb CO2, sending heat-trapping gases into the atmosphere.

Global warming and human-made climate change are not new ideas. Satellites began tracking rising global temperatures in the 1970s. Concern about anthropogenic climate change was growing and three major events in climate science occurred at the time that led to what the authors of the new analysis call in Nature Climate Change the “identification of human fingerprints in atmospheric temperature.”

In 1979, the Charney report on carbon dioxide and climate change by the US National Academy of Sciences was published, as was the Hasselmann report – considered the first serious effort to provide a statistical framework for identifying a human-caused global warming signal, and the National Oceanic and Atmospheric Administration (NOAA) started using satellites to monitor global changes in atmospheric temperatures.

On the 40th anniversary of these key events, the researchers have reanalyzed the three data sets and concluded the first two reached the five sigma level, or gold standard of certainty, back in 2005, and the third in 2016.


“Humanity cannot afford to ignore such clear signals,” the report concludes.

Of course, there are still those who refuse to accept that climate change is real, let alone directly caused by humans. Alas, not understanding something doesn’t make it not real. A consensus of 97 percent of climate scientists all agree that the thousands of peer-reviewed studies, analyses, and reports from decades' worth of data all show the same thing: It's us.

“The narrative out there that scientists don’t know the cause of climate change is wrong,” study lead author Benjamin Santer, an atmospheric scientist at the Lawrence Livermore National Laboratory, told Reuters. “We do.”

There is no “debate” amongst climate scientists, and those who suggest there is likely have their own motivation – fear, denial, greed – for stirring up a controversy that doesn’t exist. In the meantime, the rest of humanity needs to pick up the slack. According to the landmark IPCC report, this is doable if we act now