The United States earlier this month started the process of withdrawing from the 2015 Paris climate accord, making the world's largest economy the sole outlier from the agreement.
Trump, who took office in 2017, has also sought to block California from setting tighter standards on car emissions and moved to let states set their own standards on existing coal-fired power plants.
“We have an absolutely irresponsible attitude on the part of the Trump administration,” Environment Minister Teresa Ribera said during an interview with Spanish public television.
An attitude which is “irresponsible in the eyes of the planet as a whole, because what the world's biggest economy does… affects us all, but irresponsible as well for the interests of American society,” she added.
“The international community found a way to say 'no, it's important to continue to work, it's important to continue to coordinate actions', nobody is formally following President Trump, we are seeing a positive reaction.”
Spain's Socialist government offered to host this year's UN climate conference, known as COP25, after the event's original host Chile withdrew last month due to deadly riots over economic inequality.
Spanish authorities expect some 25,000 participants and 1,500 journalists from around the world to attend the two-week gathering, which gets underway on Monday in Madrid.
The US will be officially out of the Paris climate accord on Nov 4, 2020, one day after a presidential election in which Trump is seeking a second term.