WSJ has a column written by Patrick Moore, a co-founder of Greenpeace who left in 1968 and now works for the Clean and Safe Energy Coalition.

Why I Left Greenpeace
By PATRICK MOORE
April 22, 2008; Page A23
In 1971 an environmental and antiwar ethic was taking root in Canada, and I chose to participate. As I completed a Ph.D. in ecology, I combined my science background with the strong media skills of my colleagues. In keeping with our pacifist views, we started Greenpeace.
But I later learned that the environmental movement is not always guided by science. As we celebrate Earth Day today, this is a good lesson to keep in mind.
At first, many of the causes we championed, such as opposition to nuclear testing and protection of whales, stemmed from our scientific knowledge of nuclear physics and marine biology. But after six years as one of five directors of Greenpeace International, I observed that none of my fellow directors had any formal science education. They were either political activists or environmental entrepreneurs. Ultimately, a trend toward abandoning scientific objectivity in favor of political agendas forced me to leave Greenpeace in 1986.
The breaking point was a Greenpeace decision to support a world-wide ban on chlorine. Science shows that adding chlorine to drinking water was the biggest advance in the history of public health, virtually eradicating water-borne diseases such as cholera. And the majority of our pharmaceuticals are based on chlorine chemistry. Simply put, chlorine is essential for our health.
My former colleagues ignored science and supported the ban, forcing my departure. Despite science concluding no known health risks – and ample benefits – from chlorine in drinking water, Greenpeace and other environmental groups have opposed its use for more than 20 years.

Patrick continues his venting.

Sadly, Greenpeace has evolved into an organization of extremism and politically motivated agendas. Its antichlorination campaign failed, only to be followed by a campaign against polyvinyl chloride.

and closes

We all have a responsibility to be environmental stewards. But that stewardship requires that science, not political agendas, drive our public policy.

Keep this in mind if you are working on a Green Initiative and you are looking for executive support. Green has negative perceptions in some circles.