How can political liberals be environmentalists?

It is often assumed that neutralist liberalism and environmentalism are incompatible because promoting environmentally friendly policies involves endorsing a particular conception of the good life. This paper questions that assumption by showing that one important version of neutralist liberalism, John Rawls's 'justice as fairness', can allow two kinds of justification for environmental policies. First, public reason arguments can be used to justify conceptions of sustainability and environmental justice. Second, comprehensive ideals (including non-anthropocentric ideals) can be used to justify more ambitious environmental policies when two conditions are met, namely, the issue under discussion does not concern constitutional essentials or matters of basic justice; and the policy is endorsed by a majority of citizens. Rawls's willingness to allow this second kind of justification for environmental (and other) policies is defended against two objections, which claim that Rawls's democratic liberalism' is incoherent. The first objection - the 'justice' objection - is that to spend public money promoting comprehensive (environmental) ideals is inconsistent with the 'difference principle'. The 'justice' objection depends on a common Misunderstanding of the difference principle. The second objection - the 'neutrality' objection - claims that 'democratic liberalism' is inconsistent with Rawls's commitment to neutrality. The 'neutrality' objection is unconvincing because 'democratic liberalism' is 'fundamentally neutral' whereas the leading alternative is not.