[rdl6989]

I am somewhat surprised that medeival man was nearly the same height as we are now on average. I wonder what the life expectancy was then? As for greenhouse effect, I heard several years ago that a single volcanic eruption like Mt. Saint Helens releases more CO2 into the atmosphere than all human activities since the beginning of civilization.

[beezdotcom]

As for greenhouse effect, I heard several years ago that a single volcanic eruption like Mt. Saint Helens releases more CO2 into the atmosphere than all human activities since the beginning of civilization.

And the eruption of Mt. Pinatubo in the Phillipines is a good example of nature's own disruption of the ozone layer (which is also a constantly renewing resource). But it's still all our fault....

[beezdotcom]

I heard several years ago that a single volcanic eruption like Mt. Saint Helens releases more CO2 into the atmosphere than all human activities since the beginning of civilization.

By the way, I think that number is way too high - it's likely that a single volcanic eruption is still only going to release some percentage of the yearly human output of CO2. However, when you add in the constant emissions from all volcanoes, geothermal vents, decomposing vegetation, etc...human output becomes a smaller and smaller percentage.

[SunkenCiv]

I heard several years ago that a single volcanic eruption like Mt. Saint Helens releases more CO2 into the atmosphere than all human activities since the beginning of civilization. -- rdl6989

In the case of a very long, larger eruption, it could happen, probably has happened. The largest single eruption inferred from the record, during generally accepted human times, took place about 70,000 years ago off SE Asia.

However, when you add in the constant emissions from all volcanoes, geothermal vents, decomposing vegetation, etc...human output becomes a smaller and smaller percentage. -- beezdotcom

I'd also agree with this -- and there are hundreds of eruptions of various sizes each year.