Climate activist Greta Thunberg has said she will not waste her time speaking to President Donald Trump as she heads across the Atlantic on a racing yacht to attend UN summits on tackling global warming.

The 16-year-old said Mr Trump has ignored scientists and other experts about global warming, so she saw no reason why he would listen to her.

“I don’t see that if anyone else has succeeded… I am not that special,” Greta said of the US president.

“I can’t convince everyone and instead of speaking to me and the school-striking children and teenagers they should be talking to actual scientists and experts in this area.

“There’s always going to be people who don’t understand or accept the united science, and I will just ignore them, as I’m only acting and communicating on the science.

“I have just decided I’m going to do everything I can, that keeps me going, the dedication I will do everything I can.

“Also, the fact that some things are actually changing, I think the mindsets of many people are changing, even if it’s not enough, and not fast enough, that’s something, it’s not for nothing.”

Climate activist Greta Thunberg addresses a press conference in Plymouth (Ben Birchall/PA).
Climate activist Greta Thunberg addresses a press conference in Plymouth (Ben Birchall/PA)

She added: “Of course there are climate delayers who want to do everything to shift the focus of the climate crisis to something else or want to make people question the science.

“I’m not worried about that and I’m just going to do as I want to do and what I think will have most impact.”

Mr Trump has previously described concerns about climate change as “bullshit” and suggested global warming was a hoax created by China to hit US manufacturing.

Greta’s “school strikes” have inspired a global protest movement by young people demanding urgent action on climate change.

The Swede is making the trip across the Atlantic on a high-tech racing yacht, the Malizia II, so she can attend high-profile climate events in the US and Chile.

Greta, who is taking a sabbatical year from school, will be joining large-scale climate demonstrations and speaking at the UN Climate Action Summit hosted by secretary-general Antonio Guterres in New York in September.

She is also planning to visit Canada and Mexico before travelling to this year’s UN climate conference, which is taking place in Santiago, Chile, in December, making her journeys by train and bus.

The two-week sailing trip means she can attend the summits without using planes or cruise ships which cause greenhouse gas emissions.

Greta Thunberg sails to the US
Climate activist Greta Thunberg begins her voyage to the US from Plymouth on the Malizia II (Ben Birchall/PA)

She said her adventure would have challenges including seasickness but said many people in the world were suffering a lot more than that.

To keep herself occupied during the journey she has books, board games and a rabbit teddy bear, which was a gift from a friend.

“I was test sailing two days ago and we went out for several hours. I didn’t feel bad or anxious, I felt seasick for about one or two minutes, then it stopped,” she said.

“I will just have to see, get on the boat and see what happens, and that is also very exciting.

“I’ve never done anything like this before, I can’t really say what’s going to be the biggest challenge, I will have to find that out.

“I think this trip will be quite an adventure and a very new experience for me and I expect it to be challenging sometimes but also good most of the time.”

Greta Thunberg sails to the US
Greta gets a hug before she leaves Plymouth (Kirsty Wigglesworth/PA)

Greta was speaking at a press conference in Plymouth, Devon, before setting sail on Thursday afternoon.

The first anniversary of her protest movement will happen next week while she is on board the yacht.

The youngster is crossing the Atlantic in the 60ft sailing yacht, which is fitted with solar panels and underwater turbines to generate zero-carbon electricity on board.

The vessel is captained by Boris Herrmann, and Greta will also be accompanied on the two-week journey by a filmmaker, her father Svante and Pierre Casiraghi, the grandson of Monaco’s late Prince Rainier III and American actress Grace Kelly.