The Wayback Machine is most effective if you have a url, for example: http://www.epa.gov or http://epa.gov/climatechange/index.html or https://www.whitehouse.gov/energy/climate-change.
Enter the url and choose the date you need.
Another option is to try the Search Box on the right side of the main page. Once you do a search, you'll be given Advanced Search options to help you focus your search.
At this point, I recommend using the Internet Archive or perhaps DataRefuge for searching information archived on EDGI, a network of academics and non-profit organizations which is building online tools and research networks to proactively archive public environmental data and ensure its continued public availability.
Hosted by Columbia Law School's Sabin Center for Climate Change Law, the Climate Regulation Database contains archived copies of Obama-era climate change regulations, policy documents, guidance documents, and supporting materials such as regulatory impact statements, environmental impact statements, and other supplemental studies. It organizes all of these materials by agency and topic.
The Georgetown Climate Center is collecting and archiving federal climate resources in the Clearinghouse. Resources direct users to archived links or provide access to an archived link at the bottom of the resource summary. You can search by keyword or by agency.