The letter, signed by 350 experts, was sent ahead of the US president's visit to the UK this week for the NATO Leaders Meeting.
It brands Trump's views' irresponsible' and 'dangerous', as well as 'unscientific', saying he has 'ignored the warnings about climate change from scientists and national security experts'.
'Harming lives and livelihoods'
"President Trump's unscientific denial of the risks of climate change is harming lives and livelihoods of people in the United Kingdom, United States and across the world," says the letter.
"His attempts to undermine the Paris Agreement are making the world a more dangerous place and threatening the prosperity and safety of current and future generations.
"We urge you to challenge President Trump about his irresponsible approach to climate change, and seek to persuade him both to take strong domestic action to reduce greenhouse gas emissions and to join coordinated international action, including the Paris Agreement."
Climate change summit 2020
As the letter notes, the UK is likely to co-host the United Nations climate change summit in 2020, which is slated to take place in Glasgow between 9 and 20 November next year.
The decision about whether the United Kingdom will co-host the 2020 summit with Italy will be formally taken at the 2019 United Nations climate change summit, which begins in Madrid today (December 2).
Ahead of the summit, countries are expected to submit revised national pledges for cutting greenhouse gas emissions in line with the goals of the Paris Agreement.
However, the letter states, Trump has initiated the withdrawal of the United States from the Agreement, a process that is due to be completed on 4 November 2020.
He has claimed the Agreement would mean 'shutting down American producers with excessive regulatory restrictions like you would not believe, while allowing foreign producers to pollute with impunity'.
Experts say these claims are false, and also criticize the White House's website which has described the Agreement as 'fraudulent, ineffective, and one-sided'.