A UK Cabinet minister who was criticised over tweets denying climate change has admitted she did not understand the issue at the time.

Anne-Marie Trevelyan, the new International Trade Secretary, said she had some "very scary science lessons" when she was energy minister. 

She said climate change can be "catastrophic" and the Cop26 climate summit in Glasgow faces a challenge to "power past coal".

Ms Trevelyan was criticised over a series of tweets sent between 2010 and 2012 which rejected the science of climate change. 

One, sent in support of a campaign against windfarms, read: "We aren't getting hotter, global warming isn't actually happening."

Another referred to "doom-mongers and global warming fanatics".

Earlier this week, Prime Minister Boris Johnson defended Ms Trevelyan, saying "the facts change and people change their minds". 

Speaking to The Herald during a visit to Scotland, Ms Trevelyan said the tweets were written "long before" she became an MP in 2015.

She said: "My sense at the time was that there were very strong separate camps.

"I'm all about sensible, practical politics and day-to-day life.

"As an ordinary citizen, I didn't have a sense or an understanding of the way that the IPCC [Intergovernmental Panel on Climate Change] were presenting, and it sort of didn't ring true with me.

"But I think both as the science has continued but also we have seen the genuine impact that we're seeing - I've spent the last year travelling, working on Cop26 with Alok Sharma - climate change can be catastrophic in a flooding sense and fires in Australia sense."

Ms Trevelyan said she "didn't get the detail of that complex scientific argument, which is this exponential curve of heat rise". 

She added: "To that point, absolutely, 10 or 11 years ago, I hadn't investigated or understood this in any depth.

"But over the last few years, watching and understanding - and the challenge I think for us at Cop26 is to bring everyone together both to really crack the challenge, which is unabated coal power production is just appalling for CO2 emissions, and really persuading the world that we've got to power past coal, as the expression goes, for very, very real CO2 emissions reasons."

She added: "Even if we fixed that tomorrow and everyone stopped coal power - and that would be amazing - CO2 wraps the planet in a blanket and it takes 100 years to dissipate.

"So I didn't understand that 10 years ago.

"I've had some very scary science lessons, actually, when I was energy minister - but incredibly helpful to understand."

She said the younger generation are "much more tuned into" climate issues.

Asked about the prospect of a US trade deal, Ms Trevelyan said she had had a "really good meeting" with US Trade Representative Katherine Tai. 

But she said President Joe Biden's focus seemed to be "very firmly" on recovery from the pandemic and domestic issues. 

"That overarching deal absolutely is something we want to continue to work towards, but it's not imminent," she said. "We haven't got to that stage."

Elsewhere, she said she will "absolutely" work to ensure the five-year suspension of US tariffs on whisky will be extended.