In response to remarks by billionaire and former New York City mayor Michael Bloomberg at the Global Climate Action Summit in San Francisco on Thursday, climate campaigners denounced as both “absurd” and “offensive” his comparison of environmentalists demanding earth-saving policies to xenophobic supporters of Trump enthusiastically pushing to build a wall along the U.S.-Mexico border.

With new word out of his camp that Bloomberg is seriously considering a run for president in 2020 as a Democratic candidate, the billionaire media and financial mogul’s appearance at the summit—which critics have decried as being too friendly to business interests while locking out Indigenous voices and the members of the climate justice movement—drew loud protest.

Bloomberg dismissed the group for being “environmentalists protesting an environmental conference.”

“It reminds me of people who want to build a wall along the Mexican border to keep people out from a country we go to for vacations. Something’s crazy here,” Bloomberg told the crowd.

Bloomberg’s statement mocking the demonstrators was slammed by climate action leaders as “absurd and offensive,” especially coming from someone framing himself as a political leader on the issue while continuing to promote planet-killing policies like fracking and expanded reliance on oil and gas.