A real emergency declaration might be something like this:

For example, once a climate emergency is declared, Biden could divert billions of dollars from the military toward constructing renewable energy projects. Under the Defense Production Act, a law invoked by the Trump administration to boost the supply of Covid-19 medical supplies, Biden could order businesses to manufacture more clean energy and transportation technologies. He also could extend loan guarantees to industries crucial to decarbonizing the electrical grid and transportation sector, further boost

Source: What it might look like if President Biden really declared a climate emergency | Grist