Once and for all, prominent U.S. scientists are saying, Americans need to wake up, get a grip, and face the reality that not only will human-caused climate change continue to noticeably impact local weather patterns from time to time but that it could also lead to "abrupt, unpredictable and potentially irreversible" changes that will dramatically alter the lives of billions of people and the life systems supported by Earth.

Worried that Americans specifically—despite all available evidence, repeated warnings, and urgent calls for action—have largely ignored the crisis, the American Association for the Advancement of Science (AAAS) on Tuesday launched a new project—including key messages and compelling videos—designed to cut through the disinformation campaign surrounding the science of climate change while offering a direct challenge for the U.S. to finally take a leading role on the issue.

"As scientists," the statement by the AAS says, "it is not our role to tell people what they should do or must believe about the rising threat of climate change. But we consider it to be our responsibility as professionals to ensure, to the best of our ability, that people understand what we know: human-caused climate change is happening, we face risks of abrupt, unpredictable and potentially irreversible changes, and responding now will lower the risk and cost of taking action."

More marketing campaign than research paper, the AAAS project, launched under the name 'What We Know,' comes just weeks ahead of the publication of the next report by the UN's Intergovernmental Panel on Climate Change (IPCC), due to be released at the end of the month in Japan.

Citing the troublesome findings of recent polls that show too many Americans still think there is scientific disagreement about the causes and potential impacts of global warming, the AAAS offers these three specific messages they believe every American should know about the issue:

1. Climate scientists agree: climate change is happening here and now. Based on well-established evidence, about 97% of climate scientists have concluded that human-caused climate change is happening. This agreement is documented not just by a single study, but by a converging stream of evidence over the past two decades from surveys of scientists, content analyses of peer-reviewed studies, and public statements issued by virtually every membership organization of experts in this field. Average global temperature has increased by about 1.4˚ F over the last 100 years. Sea level is rising, and some types of extreme events – such as heat waves and heavy precipitation events – are happening more frequently. Recent scientific findings indicate that climate change is likely responsible for the increase in the intensity of many of these events in recent years. 2. We are at risk of pushing our climate system toward abrupt, unpredictable, and potentially irreversible changes with highly damaging impacts. Earth’s climate is on a path to warm beyond the range of what has been experienced over the past millions of years.[ii] The range of uncertainty for the warming along the current emissions path is wide enough to encompass massively disruptive consequences to societies and ecosystems: as global temperatures rise, there is a real risk, however small, that one or more critical parts of the Earth’s climate system will experience abrupt, unpredictable and potentially irreversible changes. Disturbingly, scientists do not know how much warming is required to trigger such changes to the climate system. SCROLL TO CONTINUE WITH CONTENT Never Miss a Beat. Get our best delivered to your inbox.





3. The sooner we act, the lower the risk and cost. And there is much we can do. Waiting to take action will inevitably increase costs, escalate risk, and foreclose options to address the risk. The CO2 we produce accumulates in Earth’s atmosphere for decades, centuries, and longer. It is not like pollution from smog or wastes in our lakes and rivers, where levels respond quickly to the effects of targeted policies. The effects of CO2 emissions cannot be reversed from one generation to the next until there is a large- scale, cost-effective way to scrub carbon dioxide from the atmosphere. Moreover, as emissions continue and warming increases, the risk increases.

In a series of videos featuring AAAS member scientists, the new project also hopes to cast aside the idea that large-scale dissent exists within the expert community:

___________________________________________