"In reality, the world's seven billion people are causing climate to change and our emissions of carbon dioxide and other greenhouse gases are the primary cause", said the letter, signed by AMS executive director Keith Seitter.
The U.N. Intergovernmental Panel on Climate Change has concluded that it is "extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century" - a position reiterated on EPA's own website.
If we look at President Trump's Cabinet members, it's obvious that the man who heads the Environmental Protection Agency, Scott Pruitt, is the most risky one, not just for America, but for the world.
Scientists immediately criticised Mr Pruitt's statement, saying it ignored a large body of evidence collected over decades that showed fossil fuel burning was the main factor in climate change.
Pruitt said during his confirmation hearing in January that climate change is real - breaking with President Trump and his own past statements.
Scott Pruitt, the new head of the Environmental Protection Agency, defied longstanding scientific consensus in an interview this week when he said that neither human activity nor carbon dioxide emissions are the primary cause of global warming.More news: Biden's Comments on Challenges in Cancer Care Highlight SXSW Talk
"But we don't know that yet".
"We are not familiar with any scientific institution with relevant subject matter expertise that has reached a different conclusion".
The letter ended with an open offer to work with Pruitt and his staff to better understand the science.
And Pruitt is packing EPA management with fellow fossil fuel industry-friendly staffers. The Natural Resources Defense Fund submitted a Freedom of Information Act request on Friday asking the agency for any documents Pruitt relied on to formulate his stance on climate change, including records of any meetings or other communications he has had about the topic. "Preventing the greatest consequences of climate change is imperative to the health and well-being of all of us who call Earth home..."
As Oklahoma's attorney general, Pruitt and another dozen attorney generals unsuccessfully challenged the endangerment finding in a federal appeals court. During that time he had close ties to the Sooner State's oil and gas industry. Trump made clear, after the transition of power, his plans to stop Obama's climate actions.
CBS This Morning co-host Gayle King introduced a report on the controversy by fretting: "President Trump's EPA administrator, who sued the agency repeatedly in his former job, has touched off a fierce new argument over climate change. Less expensive energy will be a big boost to American agriculture, as well".