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 US report said on 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 US 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.

The 300-page report issued by the American Meteorological Society and the National Oceanic and Atmospheric Administration (NOAA) mentioned the word “abnormal” a dozen times, referring to storms, droughts, scorching temperatures and record low ice cover in the Arctic.

Some of its key findings said that last year, the top three most dangerous greenhouse gases released into Earth’s atmosphere – carbon dioxide, methane and nitrous oxide – reached new record highs.

The annual global average carbon dioxide concentration at the Earth’s surface climbed to 405 parts per million, “the highest in the modern atmospheric measurement record and in ice core records dating back as far as 800,000 years”, said the report.