Humanity's Potentially Massive Environmental Offset

There is a reasonable chance that humanity caused the extinction of the Neanderthals. Some researchers, however "think that assembling the genome of Neandertals...is just around the corner." Once we have done this, we may be able to bring the Neanderthals back to life. In my opinion this would more than make up for all the less intelligent species we have wiped out over the last 30,000 years.

There might also be substantial benefits to us in bringing the Neanderthals back. We don't know how their minds worked. It's very possible that they could outperform humans at some tasks meaning that they could substantially aid our economy.