However, Ch 18 of the TPP (Intellectual Property) extends the copyright uniformly for all countries that signed the TPP. In general, the copyright right is extended even longer than current US law, and the TPP copyright is generally held for Dec 31 in the year of the author's death, plus 70 years. There are some exceptions which you can read in the Ch 18 link below under "Links".
Project Gutenberg Distributed Proofreaders is one organization that helps process books in PDF format to readable, rewrappable formats, and will also be affected by the TPP. In both cases, PG and PGDP will have to determine which books on file will have to be removed for a time. This means creating a massive database of author death dates, and any other info that will affect copyright.
They could certainly use your help with finding the deaths of authors, with proof. Here is a thread on PGDP (Project Gutenberg Distributed Proofreading) talking about collecting author deaths to make sure the Gutenberg Project complies with TPP when it takes effect in the US.
If you have some spare time please consider helping out PGDP.net.