A group of around two dozen American students has named President Donald Trump in a landmark lawsuit over the federal government’s climate-change policy that they claim can put their future in jeopardy.

The 21 students, one of whom is just 9 yeas old, added Trump as a party to their 20year-old suit so that litigation can continue under the new administration. Trump replaces former U.S. President Barack Obama.

While naming the new president as a party in the lawsuit might be procedural, the students said that they had been prompted to name the new president because he repeatedly challenged the science behind climate change.

Aji Piper, a 16-year-old student from Seattle, said in a statement, “I am hopeful that our case will reverse or prevent all damage our current president may inflict.”

Julia Olson, counsel for the plaintiffs, said it’s really the most imperative case on climate change in the world right now because the U.S. is most responsible for the issue.

President Trump, a Republican who took power on 20th of January, has repeatedly dismissed global warming as a “hoax” created by China to undermine the U.S. economy.