Scott Pruitt, the head of the United States Environmental Protection Agency (EPA) who has previously questioned aspects of climate change, has posed the question of whether global warming might be beneficial to humans.
Pruitt, who was nominated for the position by President Donald Trump last year, previously dismissed the scientific consensus that carbon dioxide emissions were a primary cause of climate change.
"We know humans have most flourished during times of warming trends," Pruitt told a Nevada TV station. "There are assumptions made that because the climate is warming that necessarily is a bad thing.
"Do we know what the ideal surface temperature should be in the year 2100 or year 2018? It's fairly arrogant for us to think we know exactly what it should be in 2100."
Pruitt said he wanted an "honest, transparent debate about what we do know and what we don't know so the American people can be informed and make decisions on their own".
The EPA is in agreement with the overwhelming percentage of scientists who say that rising temperatures and the environmental changes they are bringing about and will continue to bring about are a danger to human health.
"Warmer average temperatures will lead to hotter days and more frequent and longer heatwaves," the EPA website states. "These changes will lead to an increase in heat-related deaths in the United States - reaching as much as thousands to tens of thousands of additional deaths each year by the end of the century during summer months."
In March 2017, shortly after his appointment, Pruitt told CNBC: "Measuring with precision human activity on the climate is something very challenging to do and there's tremendous disagreement about the degree of impact, so no, I would not agree that [carbon dioxide] is a primary contributor to the global warming that we see.
"But we don't know that yet. We need to continue the debate and continue the review and the analysis."
The EPA has been considering whether to televise a "red team, blue team" debate on the issue of climate change.
"That's an ongoing review internally, and it's something we hope to do," Pruitt said at a hearing in December. "That would be a process where we would focus on an objective, transparent, real-time review of questions and answers around the issue of CO2."
Pruitt was nominated by Trump, who has long been a climate change sceptic. In December the president tweeted, during a period of cold weather, that the US "could use a little bit of that good old Global Warming that our Country, but not other countries, was going to pay TRILLIONS OF DOLLARS to protect against".