The ads, which also appeared in the San Francisco Chronicle and the San Jose Mercury News, cost Derwin $400,000 and feature an open letter to the Space X entrepreneur, CNN reports.

“You’ve said climate change is one of the most important issues facing mankind,” the letter begins, “Donald trump is a disaster for the fight against climate change.”

Derwin launched a $1 million campaign aimed at pressuring Musk to sever his ties to Trump, after he agreed to serve on the President’s economic advisory council.

On his website, called Elon Dump Trump, Derwin writes: “Elon Musk has become one of Trump’s most prominent supporters, despite the fact that Trump’s policies directly contradict Musk’s core values, core values shared by Tesla customers and employees.”

For more about Elon Musk, watch Fortune’s video:

In a statement to CNN, Tesla said that the company’s “reason for existing is to accelerate the advent of sustainable energy” and that “if someone wants to spend money to promote a pro-environment objective, we can think of better ways to do that than attacking the people who are most committed to that very purpose.”

Musk has defended his position on the advisory council, saying in February “Advisory councils simply provide advice and attending does not mean that I agree with actions by the Administration.”