The declaration is supposed to show that the government is taking this issue seriously. The "action" they've announced doesn't. In part that's because they're waiting on the process set by the Zero Carbon Act, the budgets and recommended reduction plans which will be released for consideration in May. But there's no reason they can't pre-empt that, and surely they could have come up with something more than this. Its not as if they don't have a pile of policy from last term waiting to go now Winston is no longer blocking the way. But instead, we've got a "hurry up and wait". Its an urgent problem, but we're not getting any real policy for half a year (plus however long it takes to implement it, so 2022). And that's assuming the government follows the Climate Change Commission's recommendations, rather than watering them down so the people destroying our country and our planet can keep on making their money.
And on the third hand, if they do that, this declaration will be great ammunition for the judicial review.