Policies can have unintended consequences when budgets are often separated from agency results, and the bureaucratic process often impedes change. And, when it is too easy for special interests to secure political influence, policies are likely to benefit those interests, rather than all of society.
Foreign policy, for instance, isn’t just about deciding when to stop terrorist organizations or to aid war-torn nations. Policymakers must negotiate complex international relationships, respond to the concerns of their constituents and navigate the special interests and companies participating in the military industrial complex. Studies  have shown that despite the best of intentions, these competing interests and goals often led to unintended, and less successful, results. Likewise, health policy is plagued with competing interests, a slow Food and Drug Administration approval process and high costs. As the past several initiatives have shown, getting health policy right is a difficult task.
This accord was never going to save the planet — and hence, dumping it won’t doom the Earth. If anything, it might trigger a search for realistic and workable fixes that don’t involve putting the entire human race on an energy diet.