ever since, he has been issuing warnings on the danger of ignoring science. >> bill mckibben: one of the things that's so important here, i think, is that we're being reminded that physical reality is real. >> wertheim: what do you mean by that? >> mckibben: we tend to forget that the physical world still is in charge. i've spent, you know, 30 years trying to get people to understand that physics and chemistry matter. that you can't spin them. they don't negotiate. they're not gonna compromise with you. you have to do what they say. >> wertheim: same goes for biology. on new year's eve, a chinese government website made quiet reference to "pneumonia of an unknown cause," clustered near a market in wuhan. it was, of course, the coronavirus. >> mckibben: biology just doesn't care. it doesn't care that it's causing a recession, you know? it's not going to back off because it's an election year. i mean, it just-- doesn't give a fig about any of that, you know? so you have to respect that, and that's hard for us because we're kind of used to a world where, you know, we run everything that