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quote:Originally posted by SimmerA third alternative is not to bother; go with the flow and hope that we or our decendants will find a way to live on a hotter planet. This view is particularly popular in the UK, partly because of our miserable weather and partly becuase of our legacy infrastructure of lead drinking water pipes.
quote:Originally posted by SimmerAs you probably noticed I wasn't being entirely serious when I suggested going with the flow as a viable option! That only works if you think global warming magically stops at mild winters and hose-pipe bans in July! That ain't necessarily so, ask the Venusians! 
quote:Carbon dioxide is the main gas caused by human activity that has been linked to global warming. Concentrations now are about 360 ppm (parts per million), but will continue to rise as emissions increase.
quote:The researchers estimate that between about 60 and 52 million years ago, CO2 concentrations reached more than 2,000 ppm. But from about 55 to 40 million years ago, there was "an erratic decline", which may have been caused by a reduction in CO2 emissions from ocean ridges and volcanoes, and by increased carbon burial. Since about 24 million years ago, concentrations appear to have remained below 500 ppm and were more stable than before, although transient intervals of CO2 reduction may have occurred during periods of rapid cooling approximately 15 and 3 million years ago.
quote:Originally posted by SimmerCertainly CO2 levels were much higher 55 million years ago. Another feature of those times was the complete absence of humans! 
quote:Originally posted by another_someoneWhich is ofcourse very different from saying that humans could not endure those conditions - after all, we are now capable of surviving at the bottom of the sea, in Antarctica, is desert conditions, and (at least for short periods of time) in outer space.
quote:The major problem in most of these environments is obtaining adequate energy and food. The environment of 55 million years ago, warm as it might have been, did not lack for potential energy or food sources that we might have tapped in to.
quote:The point is that if the planet is capable, without any humans present, of creating CO2 levels 6 times as high as anything we have today, what evidence do we have that we have anywhere near the technical capability of containing CO2 levels within the narrow (and anomalously low) band that we have become accustomed to?
quote:At which point do we ask whether we might be trying to hard to emulate King Canute?
quote:Originally posted by SimmerQuite true we might be able to survive under the conditions of 55 million years ago, I was pointing out that we don't know that because we haven't tried. I would not be too sanguine, nobody lives for long in the other environments you describe without support from a more hospitable places (with the possible exception of the damper deserts) and we know those much better than that long ago world.
quote:Also true. I wouldn't say that human survival under those conditions would be impossible but I think it would be more difficult than you would expect.
quote: Also most probably we would not be facing those conditions with all our current skills and industrial base - climate change on that scale would lead to flooding, drought and starvation, and therefore probably war, civil unrest, mass migration and disease - all of which would reduce our capacity to respond to these changes successfully. All very well putting a man on the moon but try doing it from a burning city with half your technicians dying of typhoid!
quote:Fortunately it isn't necessary for us to lock up all that CO2, it has already been done for us, immobilised in limestone and fossil fuels. All we have to do is refrain from burning all the fuel and acidifying the oceans with the waste gases.
quote:Water vapour rather than carbon dioxide in the atmosphere is the main reason why Europe's climate is warming, according to a new study.
quote:Originally posted by SimmerIt may be that we can't do anything effective about this problem. However, trying risks slower economic growth, doing nothing risks the destruction of the global economy and perhaps far worse. I think it is an easy choice.
quote:Certainly CO2 levels were much higher 55 million years ago. Another feature of those times was the complete absence of humans!