(USA TODAY) — Climate change is real, it's here and we're the cause of it, according to the USA's most comprehensive climate science report ever produced, which was released by the federal government on Friday.
Noting that the planet is now the warmest it's been the history of modern civilization, the new federal report said that "it's extremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century."
The report, officially titled the Climate Science Special Report, serves as Vol. 1 of the National Climate Assessment, a federally mandated report that's prepared by the nation's top scientists every four years for the president, the Congress and the public.
The National Climate Assessment is the fourth such report.
The contents of the report contradict claims by President Trump and his team, who have continually downplayed the human contribution to climate change and questioned the ability of scientists to predict its effects.
Earlier this year, President Trump said he planned to withdraw the U.S. from the landmark Paris climate agreement, which requires countries to establish ambitious targets to reduce the greenhouse gasses that cause global warming.
The report noted that the global atmospheric carbon dioxide concentration has now passed 400 parts per million, a level that last occurred about 3 million years ago, when both global average temperature and sea level were significantly higher than today.
"The Climate Science Special Report is the most up-to-date comprehensive report on climate science available right now anywhere on the planet," said Robert E. Kopp, a climate and sea-level rise expert at Rutgers who helped write the report. "It confirms that climate change is real, occurring today, and principally caused by human emissions."