Evidence for man-made global warming has reached a "gold standard" level of certainty, adding pressure for cuts in greenhouse gases to limit rising temperatures, scientists said yesterday.
"Humanity cannot afford to ignore such clear signals," the US-led team wrote in the journal Nature Climate Change of satellite measurements of rising temperatures over the past 40 years.
They said confidence that human activities were raising the heat at the Earth's surface had reached a "five-sigma" level, a statistical gauge meaning there is only a one-in-a-million chance that the signal would appear if there was no warming.
Such a "gold standard" was applied in 2012, for instance, to confirm the discovery of the Higgs boson subatomic particle, a basic building block of the universe.
Benjamin Santer, lead author of yesterday's study at the Lawrence Livermore National Laboratory in California, said he hoped the findings would win over sceptics and spur action.
"The narrative out there that scientists don't know the cause of climate change is wrong," he told Reuters. "We do."
Mainstream scientists say the burning of fossil fuels is causing more floods, droughts, heat waves and rising sea levels.
Sixty-two percent of Americans polled in 2018 believed that climate change has a human cause, up from 47 percent in 2013, according to the Yale Program on Climate Change Communication.