In December 2015, he delivered a speech during the United Nations Climate Change Conference in Paris, where he called the next 25 years as the "period when the impacts of climate change posed a direct threat to human civilization." He welcomed the ratification of the Paris Agreement, which he called a very important step for Hungary, as "the Carpathian Basin is more affected by climate change than several other European countries," he said. In June 2016, Áder wrote a letter to the heads of state of the world's top ten carbon dioxide-emitting countries to persuade them to tighten their reduction targets. Jobbik politician Lajos Kepli accused Áder, as while he fights for the interests of environmental protection at the international level, he failed to criticize the Orbán government for their precluding domestic policy. "[Áder] sees no problem with the taxation on solar panels, he is not bothered by the arbitrary cessation of energy efficiency tenders [...]," Kepli argued.