No Bull!
I suppose I could've searched various PBS and BBC websites and communicated with them to obtain other library materials they may have that are no longer online on their websites, before I posted. That certainly would have refreshed my memory. However, by that time, this thread would've already been off the page. But in a casual conversation in a social setting such as this forum, is that really necessary? Or is it only to be demanded of those that say something you hadn't thought of or known about before?
"Lake Overturn" is a relatively new phenomenon (at least it had not been reported in modern times before the African incidents) that has killed hundreds who were living downstream from volcanic lakes in Africa, which had become supercharged with CO2 by volcanic action beneath them. Then, when something happens that significantly disturbs the water, such as a landslide into the water or a minor earthquake, massive amounts of CO2 are suddenly released; and since it is heavier than air, in creeps down the canyons and valleys below, killing animal life and humans by suffocation. According to the Nova program, it took scientists quite some time to figure out what was happening. The program was about that scientific investigation. And yes, according to Nova, the amounts of CO2 and methane being put out every day by these volcanic vents is truly massive. Beyond comprehension really!
Yes, it is astounding, and I was somewhat skeptical, especially about the amount of gas being expelled into the atmosphere, until I also heard about it on the BBC shortwave as well; and then read about it in a Readers Digest condensed section (back when it was a fairly reliable rag). Point is, there were multiple unrelated sources.
Wikpedia currently has this to say
It is good to be generally skeptical of new data; but that skepticism, if it were honest, would motivate further investigation; before summarily dismissing it as bull. But I suppose there will always be people who would rather NOT hear any new info they hadn't heard before - obviously there must be a reason for that buried in their psyche somewhere.