The US government is expected to release Friday a major scientific report that says climate change is real, caused by human activity, and is affecting the daily lives of Americans.
The federally mandated report, known as the Fourth National Climate Assessment, is issued every four years.
It is the first to come under the administration of President Donald Trump who has labeled global warming a Chinese hoax and named fossil fuel ally Scott Pruitt to head the Environmental Protection Agency.
"Average temperatures in recent decades over much of the world have been much higher, and have risen much faster during this time period, than at anytime in the past 1,700 years or more," said a draft of the report, made public in August by the New York Times.
"It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century," it added.
"Many lines of evidence demonstrate that human activities, especially emissions of greenhouse gases, are primarily responsible for recent observed climate change."
The updated, full report will be released by the National Oceanic and Atmospheric Administration at 2 pm (1800 GMT).
The Climate Science Special Report (CSSR), which is part of the National Climate Assessment, "is an authoritative assessment of the science of climate change with a focus on the US," said NOAA in a statement.
It "serves as the foundation for efforts to assess climate-related risks and inform decision-making about responses," NOAA said.
"New observations and research have increased our scientific understanding of past, current and future climate change since the Third US National Climate Assessment (NCA3) was published in May 2014," the statement added.
Democratic Senator Al Franken of Minnesota and eight of his colleagues this week sent a letter to Trump asking "what safeguards are in place to ensure that the National Climate Assessment and the Climate Science Special Report give fair and accurate summations of the latest climate science without political interference."
The senators also asked how the Trump Administration plans to address the report's findings.