In many places, locals are pushing back, saying that forests and farmlands should not be sacrificed in the fight against climate change. Local activists say they support clean energy, but they want state regulators to be more thoughtful about where to allow development. The activists would like to see more solar projects on rooftops and previously developed sites such as parking lots and landfills. But some industry leaders say large, ground-mounted projects are much more cost-effective, and the only realistic way for states to transition away from fossil fuels. They say “not in my backyard” attitudes threaten to stall important climate work. Similarly, wind farms nationwide have long drawn some opposition for killing birds and bats and altering landscape views. As more projects spring up, regulators say it will be increasingly difficult to analyze and mitigate their collective impact on endangered species. State officials say they have not bent the rules to accommodate clean energy projects, but they acknowledge that the state’s goal of reaching 100% renewable energy by 2045 will raise difficult questions.