Environmentalism has never been wrong, but many of its methods have been. One major mistake of environmentalism has been hating technology. In fact, the environmental damage is not due to technology; it is due to wrong technology. And using better technology will solve most of the problems that environmentalism decries.
While much damage to nature can indeed be ascribed to technology, much damage is actually quite low-tech. The deforestation of the rainforests, like deforestation of Sahara by Berbers and American Southwest by the Anasazi in ages much prior, is due to slash-and-burn agriculture - a brainless age-old practice which has nothing to do with technology at all. And while many uses of technology today are just as brainless, doing away with technology is simply not a feasible option. The earth cannot sustain 7 billion subsistence farmers, and if the technological economy were to collapse most of the people around the world would be dead.
Fortunately there are real solutions, and they are technological in nature. In energy sector, it means moving to better technologies, such as Hydrogen Transmission Network (http://www.adda-enterprises.com/HTNwebsite/home.htm), which will fulfil people's water and energy needs, at present and greater levels, through a process that takes from nature nothingthat can't be replaced and returns into nature nothing harmful. In case of regular pollution in rapidly industrializing places such as China and India, the solution is as simple as using smokestack filter and water effluent filter technology that already exists in the West and applying it on their own effluent pipes and smokestacks.
One recent trend in environmentalism has been eco-feminism, which states that women are by nature carers while men are by nature destroyers, and that patriarchial social arrangements have been terrible for the planet. While there are many women who are in fact caring people, and while good case can very well be made for strengthening women's role in society, I do not see how hating men will solve the problems of the world. There is legitimate need for improving the way in which people relate to the planet. Fortunately, there is enough in human intelligence - and that means human scientific and technological intelligence - to create practical implementations for just that rightful purpose.
Then there are people in Abrahamic religions who say that it is up to God to solve this problem. Well no, it is not up to God. People created this problem; people must solve this problem, and it is not fair to ask God to clean up our mess. There are real, human, solutions to this human-made problem, and these must be put into place before expecting any kind of supernatural intervention.
Finally, the people who want to live outside of technology should be able to do so without facing criminalization or harassment. Freedom means freedom of lifestyle, and for freedom to mean anything people should have meaningful choice of lifestyle, whether they want to live with technology or without. People have right to contribute to and enjoy both human-made world of technological civilization and the non-human-made world of nature. With both being the reality ofpeople's lives, will be made the most of human existence as a being both natural and uniquely human. And that is a worthwhile state of affairs toward which to strive.