5 ms·

The distinction is one of knowledge. We have evidence that that the environment as it exists now, is a relatively stable regime. The climate has changed through

by ajb 15y ago

The distinction is one of knowledge. We have evidence that that the environment as it exists now, is a relatively stable regime. The climate has changed throughout history, but not, obviously, to the extent of rendering us extinct. If, however, we act to bring the climate out of the regime for which we have this evidence (for example, by raising the CO2 level to its highest value for 800,000 years), then with our present rudimentary understanding of the climate, we cannot predict what will happen with any great confidence. And, there is evidence that climatic changes can cause tremendous damage. So, the burden of proof should be on those who say that these changes are safe.

zeteo 15y ago
>We have evidence that that the environment as it exists now, is a relatively stable regime. Umm.. http://en.wikipedia.org/wiki/Snowball_Earth http://en.wikipedia.org/wiki/Snowball_Earth ?!
DougWebb 15y ago
<quote>The climate has changed throughout history, but not, obviously, to the extent of rendering us extinct.</quote> It's come pretty close, and that's typical. Most species that have ever existed on this planet went extinct ages ago, often during periods of drastic climate change (as far as we can tell from the archeological record.) Our own fairly recent past is the same. The latest research on the 'flood' that gave rise to flood myths in every civilization in Southern Europe, the Middle East, and North Africa, suggests that the Mediterranean Sea was a fertile populated valley during the last ice age. But when the ice age ended due to natural climate change, the rising Atlantic broke through the natural dam at Gibraltar and flooded the valley, and into the Black and Red seas, up the Nile, etc. That's a massive natural disaster that must have wiped out a pretty big chunk of humanity. It was probably repeated on a smaller scale around the world too, as seaside villages were flooded out by the rising oceans and likely increase in the number of storms as the world warmed up.
- jamii 15y ago
  Even more dramatic, a number of genetic studies suggest that hominids faced near extinction more than once eg http://www.scientificamerican.com/article.cfm?id=early-human-population-size-genetic-diversity http://www.scientificamerican.com/article.cfm?id=early-human... estimates a total population of around 50k.

by ajb 15y ago

zeteo 15y ago

>We have evidence that that the environment as it exists now, is a relatively stable regime. Umm.. http://en.wikipedia.org/wiki/Snowball_Earth http://en.wikipedia.org/wiki/Snowball_Earth ?!

DougWebb 15y ago

<quote>The climate has changed throughout history, but not, obviously, to the extent of rendering us extinct.</quote> It's come pretty close, and that's typical. Most species that have ever existed on this planet went extinct ages ago, often during periods of drastic climate change (as far as we can tell from the archeological record.) Our own fairly recent past is the same. The latest research on the 'flood' that gave rise to flood myths in every civilization in Southern Europe, the Middle East, and North Africa, suggests that the Mediterranean Sea was a fertile populated valley during the last ice age. But when the ice age ended due to natural climate change, the rising Atlantic broke through the natural dam at Gibraltar and flooded the valley, and into the Black and Red seas, up the Nile, etc. That's a massive natural disaster that must have wiped out a pretty big chunk of humanity. It was probably repeated on a smaller scale around the world too, as seaside villages were flooded out by the rising oceans and likely increase in the number of storms as the world warmed up.

jamii 15y ago
Even more dramatic, a number of genetic studies suggest that hominids faced near extinction more than once eg http://www.scientificamerican.com/article.cfm?id=early-human-population-size-genetic-diversity http://www.scientificamerican.com/article.cfm?id=early-human... estimates a total population of around 50k.