I'm currently weighing between these two specializations before I begin my master degree in Environmental Sciences.
On one hand, Environmental Economics looks more "practical". It links economic development and environmental problems together, focuses on cost-effectiveness and efficiency of policy options so I think its career impact might be easier to measure and foresee. But a quick Google search shows that it seems to have less job opportunities than Environmental Policy. It certainly isn't as popular as a topic like Environmental Policy, which for me is a field that needs a more urgent change.
I also don't have any background in Economics at all, but I'm willing to learn more about it. Although I'm worried that an intense, two year program might not be the best use of time for someone who has no previous knowledge on microeconomic theory to begin from scratch.
I know climate change isn't a top priority of EA but would love to hear some advices regarding which of these two specializations I should focus on.