Most species have died out due to evolution of superior competition or climate change. The impacts of climate change on current populations are readily apparent and the fossil record is clear that there have been many large changes in climate. Species go extinct continuously not just during mass extinctions of which some, many, or all may be due to impacts.

There is also evidence that some large impacts did not cause mass extinctions, a lack of craters corresponding to most mass extinctions (may have been obliterated by time), and nonimpact explanations for some mass extinctions so there is by no means any consensus that even large mass extinctions are mostly due to impacts. Authoritative and incorrect blanket statements such as this from Peiser who has no relevant training or experience in terms of paleontology or biology is is one of several reasons I no longer routinely visit CCNet.

At least he does a good job promoting the serious potential issue of impacts, but his willingness to jump in front of front of those with more expertise (and I'm not talking about me or Grondine for sure!) as a public mouthpiece for the issue also irritates me.

Regards,
Mark