A German teenager dubbed the “anti-Greta” – climate sceptics’ answer to the schoolgirl activist Greta Thunberg – is set to address the biggest annual gathering of US grassroots conservatives.

Related: Greta Thunberg and Malala Yousafzai meet at Oxford University

Naomi Seibt, 19, who styles herself as a “climate sceptic” or “climate realist”, will this week address the Conservative Political Action Conference (CPAC) near Washington, joining speakers including Donald Trump and Vice-President Mike Pence.

Seibt is in the pay of the Heartland Institute, a thinktank closely allied with the White House that denies established science showing humans are heating the planet with dangerous consequences.

CPAC will be the biggest stage yet for Seibt, a so-called “YouTube influencer” who tells her followers Thunberg and other activists are whipping up unnecessary hysteria by exaggerating the climate crisis.

Related Video: Children Around the World Join Climate Strike

“Climate change alarmism at its very core is a despicably anti-human ideology,” she has said.

The teenager, from Münster in western Germany, claims she is “without an agenda, without an ideology”. But she was pushed into the limelight by leading figures on the German far right and her mother, a lawyer, has represented politicians from the Alternative für Deutschland (AfD) party in court.

Seibt had her first essay published by the “anti-Islamisation” blog Philosophia Perennis and was championed by Martin Sellner, leader of the Austrian Identitarian Movement, who has been denied entry to the UK and US because of his political activism.

A Facebook post by the AfD youth wing names Seibt as a member and she spoke at a recent AfD event, though she has denied membership of the party.

In May 2019 she posted her first video on YouTube, reading out verses submitted for a poetry slam competition organised by the AfD.

The impact of the clip and its follow-ups put her on the radar of the Heartland Institute, which is based in Chicago. It has lobbied on behalf of the tobacco and coal industries but recently concentrated its efforts on challenging the scientific consensus on climate change.

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Last December, as Thunberg addressed the United Nations’ Cop25 global warming summit in Madrid, Seibt gave the keynote speech at a rival conference organised by the Heartland Institute a few miles away.

In a sting operation carried out for German broadcaster ZDF and investigative outlet Correctiv, the Heartland Institute strategist James Taylor told journalists posing as potential donors his thinktank had signed up Seibt to record climate change sceptic videos for young people.

Seibt has admitted that she receives “an average monthly wage” from the institute. According to official figures, the average net monthly income in Germany is just under €1,900 (£1,590, $2,066).

The Heartland website features a low-budget video introducing Seibt, who speaks to the camera from what appears to be a home.

“I’ve got very good news for you,” she says. “The world is not ending because of climate change. In fact, 12 years from now we will still be around, casually taking photos on our iPhone 18s

“We are currently being force-fed a very dystopian agenda of climate alarmism that tells us that we as humans are destroying the planet. And that the young people, especially, have no future – that the animals are dying, that we are ruining nature.”

In another film, Naomi Seibt vs Greta Thunberg: Whom Should We Trust?, Seibt says: “Science is entirely based on intellectual humility and it is important that we keep questioning the narrative that is out there instead of promoting it, and these days climate change science really isn’t science at all.”

Seibt has also uploaded a video with the title Message to the Media – HOW DARE YOU – an obvious reference to a speech by Thunberg at the UN in which she rebuked world leaders: “We are in the beginning of a mass extinction, and all you can talk about is money, and fairytales of eternal economic growth. How dare you!”

Thunberg began her activism at 15 by missing school and camping outside the Swedish parliament. She has since met the pope, addressed members of Congress in Washington and heads of state at the UN and helped inspire 4 million people to join a global climate strike. Last year she became the youngest Time magazine Person of the Year, much to Trump’s chagrin.

The Washington Post observed: “If imitation is the highest form of flattery, Heartland’s tactics amount to an acknowledgment that Greta has touched a nerve, especially among teens and young adults.”

Related: Malena Ernman on daughter Greta Thunberg: ‘She was slowly disappearing into some kind of darkness’

Since Trump’s election, CPAC has paraded hard-right figures such as the former White House officials Steve Bannon and Sebastian Gorka as well as numerous climate sceptics.

In his speech there last year, the president mocked the Green New Deal, proposals championed by Democrats including Alexandria Ocasio-Cortez.

“No planes,” the president said. “No energy. When the wind stops blowing, that’s the end of your electric. ‘Let’s hurry up. Darling, darling, is the wind blowing today? I’d like to watch television, darling.’”

Connor Gibson, a researcher for Greenpeace USA, said: “Climate science is understood by a majority of Americans, liberal and conservative alike. Unfortunately, you won’t meet any of those people, or any climate scientists, at an event like CPAC.

“The Heartland Institute is funnelling anonymous money from the US to climate denial in other countries. It relies on the media to advance false equivalence strategies to attempt to normalise fringe beliefs. Climate denial is not a victimless crime, and it’s time for the perpetrators to be held accountable.”