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Short answer is: Its irrelevant! Whether humans are making a noticeable contribution to our climate change is not really the issue. The true concern is whether sea levels will rise and inundate Florida, Bangladesh, and 50 or so of the world's greatest cities (see list below). The evidence is undeniable that our global climate is warming. What is worse is that the are few reasons to expect that the trend will change anytime soon - but rather will continue for decades into the future. If current trends cause the release of large amounts of methane which have been trapped in frozen tundra for millenia, this could cause a dramatic worsening of global warming. Some scientists believe this could develop into a runaway warmup - as on Venus where the surface temperature is 482 degrees Celsius ( = 900 Fahrenheit). One important point is that as the Earth warms up, the oceans warm up. When water warms up it expands. The oceans average 4000 meters deep. The coefficient of expansion is 0.00021 meters per degree Celsius. This means that if the oceans warm up by one degree Celsius, then sea levels will rise by 4000 * 0.00021 = 0.84 meters (= 2.75 feet). Thus 2 degrees of warming of the oceans would produce an increase in sea levels by 1.68 meters or 5.5 feet - which would submerge nearly all of Tuvalu and half of Bangladesh. Of course another factor is the melting of the ice fields in Greenland and Antarctica. The volume of ice in Greenland is estimated at about 2,600,000 cubic kilometers. It if all melted, it would raise sea levels by about 6.5 meters (= 21.3 feet). The volume of ice in Antarctica is about 30,100,000 cubic kilometers. If all of that melted, it would raise sea levels by about 73.5 meters (= 241 feet). No one is expecting either of these events to happen in the next several thousand years - but that is the potential damage. The global warming skeptics say that humans are not responsible for global warming. I say that if Florida and Bangladesh disappear into the ocean, who will care if "we" were responsible or if it is just a periodic warming of our climate which occurs every 100 million years or so. Between around 250 and 65 million years ago, shallow oceans occasionally covered parts of North America and Eurasia. Clearly we don't want Texas, Oklahoma, Kansas, etc. covered by oceans again. Whether the current warming trend is natural or not, we must act soon in order to prevent losing our great costal cities (see following list).
Comments? Email me at crwillis@androidworld.com
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