A sweeping new U.S. government report concludes that humans have pushed global temperatures to the highest level seen by modern civilization, defying the Trump administration’s pronouncements that climate change is a hoax or based on unsettled science. The report, produced by 13 agencies as part of the congressionally required National Climate Assessment, reinforced years of research that shows human activity was the main reason temperatures have soared in the past century — and they are likely to keep climbing, boosting sea levels and threatening environmental disasters. Robert Kopp, a climate scientist at Rutgers University, report contributor, and co-director of the Lab, said the findings “reaffirmed that climate change is real, that humans are the dominant cause of warming, and that it is having an effect in the U.S. And those effects will grow more severe as long as we continue to emit carbon dioxide into the atmosphere.”