The government’s National Climate Assessment cited human influence as the "dominant cause of the observed warming since the mid-20th century." The report affirms that climate change is driven almost entirely by human action, warns of a worst-case scenario where seas could rise as high as eight feet by the year 2100, and details climate-related damage across the United States that is already unfolding as a result of an average global temperature increase of 1.8 degrees Fahrenheit since 1900. When it comes to rapidly escalating levels of greenhouse gases in the atmosphere, the report states, “there is no climate analog for this century at any time in at least the last 50 million years.”
National Oceanic & Atmospheric Administration (NOAA) scientist David Fahey in Boulder is one of the lead authors of the study which draws on research from numerous government agencies. The full report is available for download via the The Washington Post.
“It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century,” the document reports. “For the warming over the last century, there is no convincing alternative explanation supported by the extent of the observational evidence.”