I found this fascinating article about global warming, by Elizabeth Kolbert, tying the rise in atmospheric CO2 concentration with rising sea levels. Here's just a tiny snippet:
|....A few years ago, in an article in Nature, the Dutch chemist Paul Crutzen coined a term. No longer, he wrote, should we think of ourselves as living in the Holocene, as the period since the last glaciation is known. Instead, an epoch unlike any of those which preceded it had begun. This new age was defined by one creature—man—who had become so dominant that he was capable of altering the planet on a geological scale. Crutzen, a Nobel Prize winner, dubbed this age the Anthropocene. He proposed as its starting date the seventeen-eighties, the decade in which James Watt perfected his steam engine and, inadvertently, changed the history of the earth.|
In the seventeen-eighties, ice-core records show, carbon-dioxide levels stood at about two hundred and eighty parts per million. Give or take ten parts per million, this was the same level that they had been at two thousand years earlier, in the era of Julius Caesar, and two thousand years before that, at the time of Stonehenge, and two thousand years before that, at the founding of the first cities. When, subsequently, industrialization began to drive up CO2 levels, they rose gradually at first—it took more than a hundred and fifty years to get to three hundred and fifteen parts per million—and then much more rapidly. By the mid-nineteen-seventies, they had reached three hundred and thirty parts per million, and, by the mid-nineteen-nineties, three hundred and sixty parts per million. Just in the past decade, they have risen by as much—twenty parts per million—as they did during the previous ten thousand years of the Holocene.
For every added increment of carbon dioxide, the earth will experience a temperature rise, which represents what is called the equilibrium warming. If current trends continue, atmospheric CO2 will reach five hundred parts per million—nearly double pre-industrial levels—around the middle of the century. It is believed that the last time CO2 concentrations were that high was during the period known as the Eocene, some fifty million years ago. In the Eocene, crocodiles roamed Colorado and sea levels were nearly three hundred feet higher than they are today.
For all practical purposes, the recent “carbonation” of the atmosphere is irreversible. Carbon dioxide is a persistent gas; it lasts for about a century. Thus, while it is possible to increase CO2 concentrations relatively quickly, by, say, burning fossil fuels or levelling forests, the opposite is not the case. The effect might be compared to driving a car equipped with an accelerator but no brakes.
The long-term risks of this path are well known. Barely a month passes without a new finding on the dangers posed by rising CO2 levels—to the polar ice cap, to the survival of the world’s coral reefs, to the continued existence of low-lying nations. Yet the world has barely even begun to take action. This is particularly true of the United States, which is the largest emitter of carbon dioxide by far. (The average American produces some twelve thousand pounds of CO2 emissions annually.) As we delay, the opportunity to change course is slipping away. “We have only a few years, and not ten years but less, to do something,” the Dutch state secretary for the environment, Pieter van Geel, told me when I went to visit him in The Hague....
The article concludes with the following warning:
|....Climate records also show that we are steadily drawing closer to the temperature peaks of the last interglacial, when sea levels were some fifteen feet higher than they are today. Just a few degrees more and the earth will be hotter than it has been at any time since our species evolved. Scientists have identified a number of important feedbacks in the climate system, many of which are not fully understood; in general, they tend to take small changes to the system and amplify them into much larger forces. Perhaps we are the most unpredictable feedback of all. No matter what we do at this point, global temperatures will continue to rise in the coming decades, owing to the gigatons of extra CO2 already circulating in the atmosphere. With more than six billion people on the planet, the risks of this are obvious. A disruption in monsoon patterns, a shift in ocean currents, a major drought—any one of these could easily produce streams of refugees numbering in the millions. As the effects of global warming become more and more apparent, will we react by finally fashioning a global response? Or will we retreat into ever narrower and more destructive forms of self-interest? It may seem impossible to imagine that a technologically advanced society could choose, in essence, to destroy itself, but that is what we are now in the process of doing.|
One hundred years from now, people sunbathing in their swimsuits along the Arctic Circle can thank George Bush-war, among other past leaders, for their contribution to the world's new climate.