Even as few as five years ago Dr. Hansen would probably be referred to as an "alarmist" (or a "fearmonger" by some on the right) for the claims he makes in his review. And yet with global warming so much in the news as of late and the Supreme Court set to hear a case on the regulation of greenhouse gasses, and the realization that there is no real debate in the scientific community as to whether or not global warming is taking place, it is impossible to be completely dismissive of his claims unless you have an ideological axe to grind. As it is, Dr. Hansen forecasts a very grim future for us if we do not abandon what he refers to as the "business-as-usual" approach:
If emissions of greenhouse gases continue to increase at the current rate—"business as usual"—then the rate of isotherm movement will double in this century to at least seventy miles per decade. If we continue on this path, a large fraction of the species on Earth, as many as 50 percent or more, may become extinct.
The business-as-usual scenario yields an increase of about five degrees Fahrenheit of global warming during this century...The last time that the Earth was five degrees warmer was three million years ago, when sea level was about eighty feet higher.
...In that case, the United States would lose most East Coast cities: Boston, New York, Philadelphia, Washington, and Miami; indeed, practically the entire state of Florida would be under water. Fifty million people in the US live below that sea level. Other places would fare worse. China would have 250 million displaced persons. Bangladesh would produce 120 million refugees, practically the entire nation. India would lose the land of 150 million people.
This is what Florida would look like under 20 feet of water. 80 feet is impossible imagine. What would the end result be?
If human beings follow a business-as-usual course, continuing to exploit fossil fuel resources without reducing carbon emissions or capturing and sequestering them before they warm the atmosphere, the eventual effects on climate and life may be comparable to those at the time of mass extinctions. Life will survive, but it will do so on a transformed planet. For all foreseeable human generations, it will be a far more desolate world than the one in which civilization developed and flourished during the past several thousand years.
Dramatic language without a doubt. And yet "transformed" is almost too benign a world for what our world would look like centuries from now if global warming continues unchecked.
Dr. Hansen also believes that we are very near the point at which we will no longer be able to reverse the process; what he refers to as the "tipping point" (a term he uses in an earlier article for the NY Review of Books), a point of no return:
[B]ecause of the global warming already bound to take place as a result of the continuing long-term effects of greenhouse gases and the energy systems now in use, the two-degree Fahrenheit limit will be exceeded unless a change in direction can begin during the current decade. Unless this fact is widely communicated, and decision-makers are responsive, it will soon be impossible to avoid climate change with far-ranging undesirable consequences. We have reached a critical tipping point.
And yet, Dr. Hansen holds out hope that we can change our ways. For evidence, he turns to the CFCs and the crisis over the ozone layer:
The public, responding to the warnings of environmental groups, boycotted frivolous use of CFCs as propellants for hair spray and deodorant, and chose non-CFC products instead. The annual growth of CFC usage plummeted immediately from 10 percent to zero. Thus no new facilities to produce CFCs were built. The principal CFC manufacturer, after first questioning the scientific evidence, developed alternative chemicals. When the use of CFCs for refrigeration began to increase and a voluntary phaseout of CFCs for that purpose proved ineffective, the US and European governments took the lead in negotiating the Montreal Protocol to control the production of CFCs. Developing countries were allowed to increase the use of CFCs for a decade and they were given financial assistance to construct alternative chemical plants. The result is that the use of CFCs is now decreasing, the ozone layer was damaged but not destroyed, and it will soon be recovering.
So action, even quick action, can be taken. But the job of alerting the public to the dangers of global warming is considerably more difficult:
Scientists present the facts about climate change clinically, failing to stress that business-as-usual will transform the planet. The press and television, despite an overwhelming scientific consensus concerning global warming, give equal time to fringe "contrarians" supported by the fossil fuel industry. Special interest groups mount effective disinformation campaigns to sow doubt about the reality of global warming. The government appears to be strongly influenced by special interests, or otherwise confused and distracted, and it has failed to provide leadership.
But there is hope that the public can be alerted to the consequences of global warming. It's become clear that a vast majority of Americans on both the left and the right are concerned about the environment, and more and more Americans are becoming aware of the seriousness of global warming. That many Americans do not feel that strong action is warranted on global warming just yet is due largey to the obfuscation being practiced by conservative pundits and GOP politicians and think-tanks that are in the employ of industries that would prefer no more regulation. And yet it is becoming clear that there is a consensus in the scientific community that global warming is real, and the only debate is on how profound the consequences of that warming will be.
But as Dr. Hansen says, we only have so much time. I for one don't know if we have only ten years, or if we have twenty, or thirty (certainly we do not have a century to act.) But change on this cannot occur too soon. Whether or not we have reached the tipping point at which we cannot reverse the changes to our planet, we still continue to do more damage the closer we get to that point, and the more damage we do, the longer it will take for the planet to heal. If you've been following the furor over Ron Suskind's new book, you know that Vice President Cheney believes that even a one-percent chance that an enemy could get nukes justifies the strongest of military responses; the seriouness of the danger lowers the bar for action to nearly nothing. Well my friends, there's about a one-hundred percent chance that we're going to damage our planet in some way if we continue on this path, and in my mind a better than one-percent chance that we're going to damage it in a profound way that will alter the course of human and natural history. If that isn't a call to action, then nothing is.