Four prominent climate scientists who published an open letter on Sunday about the benefits of nuclear power are receiving push back from some climate experts and environmental groups, including Greenpeace, Friends of the Earth (FOE), and the Sierra Club.

The letter, from scientists James Hansen, Ken Caldeira, Tom Wigley, and Kerry Emmanuel, advocates the development of “safer nuclear energy systems,” and states that opposition to nuclear power threatens the ability to respond to climate change.

“While it may be theoretically possible to stabilize the climate without nuclear power, in the real world there is no credible path to climate stabilization that does not include a substantial role for nuclear power,” the letter reads.

The prominent climate scientists’ “letter to policy influencers” evoked responses from several leading environmental groups and individuals who respectfully disagree that nuclear power is a safe, or viable option.

“While we respect Dr. Hansen and his advocacy to raise the alarm about catastrophic climate change, we thoroughly disagree that nuclear power has any role to play in addressing the threat posed by global warming,” said Jim Riccio, a nuclear power analyst with Greenpeace. “If we are to abate the worst impacts of climate change, we need solutions that are fast, affordable, and safe. Nuclear is none of these.”

Michael Brune, executive director of the Sierra Club expressed similar sentiments. “While we agree that the climate crisis is the most urgent challenge of our time, this group fails to acknowledge that wind, solar, and efficiency are the faster, cheaper, and safer way to fight the climate threat,” he said. “If Fukushima, Chernobyl, and Three Mile Island have taught us anything, it’s that nuclear plants are too expensive, too slow to build, and too risky.”

Joe Romm, the Founding Editor of Climate Progress, points out that the letter is “mis-addressed and misses the key point about nuclear power – because it is so expensive, especially when done safely, the industry has no chance of revival absent a serious price on carbon.”

“While solar power and wind power continue to march down the experience curve to ever lower costs – solar panels have seen a staggering 99% drop in cost since 1977 – nuclear power has been heading in the opposite direction,” Romm writes.

Even if every environmental groups dropped their objections to nuclear power, the industry would likely be in the same position it’s in now. “The countries where nuclear has dead-ended are market-based economies where the nuclear industry has simply been unable to deliver a competitive product,” he says.

Romm further notes that the groups who actually blocked nuclear power from progressing are those who prevented efforts to make nuclear power more cost-competitive. Aside from the issues of safety and waste disposal, nuclear power plants are uncompetitive.

After Fukushima, lawmakers in several countries had very strong reactions regarding their own nuclear energy programs. China suspended approvals for new nuclear reactors pending a safety review, Italy refused new nuclear reactors for the second time since Chernobyl, and Germany decided to accelerate its phaseout of nuclear power, which it initiated after Chernobyl.

In the United States, the disaster did not spark a policy response, although Americans’ support for building more nuclear power plants dropped to 42 percent.

US Energy Secretary Ernest Moniz is an advocate of nuclear energy as well as hydraulic fracturing. Moniz is a nuclear physicist who was a consultant for BP from 2005 to 2012. In 2011, he wrote “Why We Still Need Nuclear Power: Making Clean Energy Safe and Affordable.” In the report, Moniz states that “It would be a mistake… to let Fukushima cause governments to abandon nuclear power and its benefits.”

According to Romm, renewable energy like solar and wind power should play the major role in our future energy economy. He refutes the notion that new, “safer nuclear power systems” are a viable solution to our energy and climate issues. He writes,

It would be astounding if a technology that exists only in PowerPoint presentations — magical small, cost-effective, fail-safe nuclear reactors — could possibly be researched, developed, demonstrated, and then scaled up faster than a host of carbon-free technologies that are already commercial today. And remember, most of those technologies, like solar and wind, have actually demonstrated a positive learning curve, unlike nuclear reactors!

Alisha is a writer and researcher with Ring of Fire. Follow her on Twitter @childoftheearth.