A massive U.S. report concludes the evidence of global warming is stronger than ever, contradicting a favorite talking point of top Trump administration officials, who downplay human's role in climate change. The report released Friday is one of two scientific assessments required every four years. A draft showing how warming affects the U.S. was also published. "A lot of what we've been learning over the last four years suggests the possibility that things may have been more serious than we think," said Robert Kopp of Rutgers University, Lab co-directorm, and one of dozens of scientists inside and outside the government who wrote the reports.