Whatever Bernie Sanders thinks of Hillary Clinton’s presidential qualifications, the former secretary of state is “uniquely unsuited” to the task of stopping climate change, author and activist Naomi Klein writes in a new op-ed for The Nation .

Combating climate change “requires a willingness to go head-to-head with the two most powerful industries on the planet—fossil fuel companies and the banks that finance them,” she writes. “Hillary Clinton is uniquely unsuited to this task.”

Among all the uncertainties in the presidential race this year, one thing is certain, Klein says: “The Clinton camp really doesn’t like talking about fossil fuel money.”

Following her viral face-off with a Greenpeace campaigner last week, Clinton was asked by another climate activist at a Pittsburgh rally on Thursday night if she would reject money from fracking lobbyists—to which Clinton laughed and said, “Read the articles,” likely referring to recent reporting by the New York Times and the Washington Post which seemed to debunk the idea that Clinton had taken campaign contributions from oil and gas companies.

“We’ve done our research,” the activist, Sage Lincoln, responded. Watch:

Greenpeace has previously reported that Clinton took more than $300,000 from people working for fossil fuel companies and an additional $1.4 million in “bundled and direct donations” from registered fossil fuel lobbyists.

Lincoln, a Pittsburgh native, told the climate group 350 Action on Thursday that she was particularly concerned over Clinton’s ties to fossil fuels because “despite having no family history of asthma, me and two of my siblings have developed it.”

“One of the reasons for the bad air quality is clear: there is fracking occurring everywhere in Southwestern Pennsylvania,” Lincoln said. “It’s in our country parks, our backyards, and even within a stone’s throw of the nearby Mars School District. Climate change is dramatically impacting us globally and locally, and we must do everything in our power to curb emissions.”