Planet-warming greenhouse gases surged to new highs as abnormally hot temperatures swept the globe and ice melted at record levels in the Arctic last year due to climate change, a major U.S. report said Wednesday.

The annual State of the Climate Report, compiled by more than 450 scientists from over 60 countries, describes worsening climate conditions worldwide in 2017, the same year that U.S. President Donald Trump pulled out of the landmark Paris climate deal.

The United States is the world's second leading polluter after China, but has rolled back environmental safeguards under Trump, who has declared climate change a "Chinese hoax" and exited the Paris deal signed by more than 190 nations as a path toward curbing harmful emissions.