Before I go on, I think it would be helpful to state up front my claim to expertise in this matter. I have advanced degrees in geology and biology. In geology, I studied paleoclimatology and worked on the microfossil identifications for the Glacial Lake Estancia project with Dr. Roger Andersen. As a biologist, my focus was on ecology and evolution, and my specific interest was in the desert soil ecology of cryptogamic crusts. I also taught Genetics to undergraduates as an instructor (sometimes called a lecturer). In my first area of interest, paleoclimate, I learned quite a bit about the influences on climate on the earth and about the earth's history of climate change. In my second area of interest, desert ecology, I was involved in ongoing studies of desertification in the southwestern US, through work on the lands of the Servilleta Long Term Ecological Research Center and also at the Jornada del Muerte.
As I have been moving through my days, reading blogs, reading the newspaper, and having discussions, I have noticed that with respect to global climate change, science and politics are getting twisted together in a very confusing way. On the one hand, the science as it is reported in the popular press gets simplified and stated in absolute terms. Then political types get a hold of the simplification of results and use it to push very specific agendas. For those who oppose the political agendas that have been tied to scientific information, it has become almost de rigeur to deny the scientific evidence lock, stock and barrel and call it "junk" science. The fascination of scientific discussion is lost to both of these positions and the argument descends to insult and name calling that spirals to the point where lines are drawn in the concrete, and neither "side" can even bear to listen to the other. In other words, the science is lost in the political ideologies of left and right.
Those who embrace the ideologies as described above are generally not scientists, although politically astute scientists do use prevailing ideologies to get funding. We are human, after all. When scientists enter the popular discussion they are often at a disadvantage because many forget that the popular discussion is not conducted to get at a better understanding of physical reality and how it works, but rather to demonstrate the absolute rightness of one ideology over another.
Science does not work by proclaiming an absolute position and then going out to find evidence to support it. Rather, it works by hypothesis testing. A question is posed and then an experiment is developed to test the hypothesis. Information is extracted regardless of whether the hypothesis or the null is confirmed by the experiment. Of course, funding proposals being what they are, most scientists would rather be able to confirm the hypothesis rather than the null, and so we generally do a lot of ground work in order to make sure the hypothesis is a good one before commiting time, money, and professional reputation to it. This requires the willingness to spend much time learning the field. The purpose of all of this is advance our knowledge of physical reality bit by bit.
Most working scientists spend their years of research developing ideas that support the dominant paradigm of their field. In Geology, for example, that paradigm is plate tectonics, in Chemistry, it is the quantum structure of the atom, and in Biology it is evolution by natural selection. It is a rare and interesting time when the current paradigm no longer supports everything that is being discovered, and a new paradigm is developed. I was fortunate to begin my studies in Geology during exciting times when the paradigm shift to plate tectonics was taking place. A fascinating popular account of this shift is The Road to Jaramillo: Critical Years of the Revolution in Earth Science, by William Glen.
There is a popular misconception about what happens to previously developed knowledge in the event of a paradigm shift. It does not go away or cease to be a description of reality. It is, rather, subsumed under the new paradigm. For example, Newton's laws did not cease to operate when the revolution in Physics precipitated Quantum Mechanics in the early years of the 20th centuries.
Now that we've got that background explicated, let's talk about what we know about the science of global climate change. That the earth's climate has changed over time and continues to do so is not in question among scientists. The position of the continents now--particularly the fact that the north pole is positioned in ocean almost surrounded by continental landmasses, does indicate that the earth can be expected to undergo bouts of glaciation and inter-glacial periods, as has been occuring since the beginning of the Pleistocene. Cyclical warming and cooling can be expected as long as the continents remain the their present configuration.
Interglacial periods like the one we are in now, which are characterized by sea-level rises and warming of the earth's average temperature. Toward the end of these periods, the average temperature rises sharply and is followed by renewed glacial advances. This creates sea-level drops and cooling of the earth's average temperature.
These major changes also cause changes in precipitation patterns expected in different regions across the earth's surface. For example, here in New Mexico, glacial advances trigger "pluvials" or periods of higher rainfall, whereas glacial retreats are marked by dryer, desert conditions. This is turn changes the latitude and altitude of the major life zones. Again, in New Mexico, geomorphological studies and paleo-pollen studies indicate that what is now low desert grassland was often covered by water (such as Glacia Lake Estancia in the present Estancia Basin, and Glacial Lake San Agustin on what is now the plains of San Agustin). The other life zones were shifted down in altitude accordingly, with the pinon-juniper woodlands being below 5,000 feet, the Ponderosa Pine zones being below 6,000 feet, and so forth, all the way to a lower treeline in montaine topography.
The point here is that the earth's climate has changed in the past and can be expected to change in the future. Human beings tend to see things through the lens of a very short lifespan in comparison to the age of the earth, and so we tend to think that the way things are is the way things always were and always will be. To think about climate change as a dynamic process on the earth, requires us to take a longer view, one in which our history is an almost miniscule segment in the extremely long timeline of earth history.
There is also ample evidence that human activity has created a faster warming of the earth than has been seen at the end of other interglacial periods. Oxygen isotope data from the poles indicates that temperatures have risen before the beginning of each of the past four glacial advances, however the rate of change for the current average temperature rise appears to be much steeper than for the ends of any other interglacial period since the beginning of the Pleistocene. However, there are different ideas about how much steeper because there is error in these reconstructions.
This is not the first time in earth's history that life has altered conditions. Think about the Oxygen revolution at the beginning of the Phanerozoic. The evolution of photosynthetic bacteria changed the atmosphere of the earth to one that is oxygen-rich. The beautiful Banded Iron Formations in the Mesabi Range are only one piece of evidence of this major change. This was a major change that allowed oxygen-using life forms to evolve and pushed the anaerobic archaebacteria into very limited oxygen poor environments, such as the deep sea vents. I could go on and on about the alterations that the various phyla of life have made to the earth's environment. Think about the invasion of the land by plants and then animals. Think about the evolution of flowering plants in the early Cenezoic.
None of the above is controversial among scientists. There is ample evidence from a multitude of scientific disciplines, including Physics, Astronomy, Paleontology, Biology, Geology, Chemistry, Biochemistry and Molecular Biology. If so, why the controvery?
I think much can be explained by the ideological uses to which this information has been put. In the world of politics, some people have used this evidence to make specific predictions, and based on these predictions, they have demanded certain political solutions that affect our current ways of doing business. Others, opposed to these solutions have then rejected the evidence rather than attack the proposed solutions.
In effect, one ideological camp is proclaiming: The climate is changing (scientifically supported) and therefore we must change our economic system (science cannot determine this) in order to stop the climate change (dubious endeavor). One might wonder if the real ideological goal here is to use the idea of climate change in order to further an anti-industrial, anti-capitalist political agenda. Another camp seems to be proclaiming: The climate is changing (scientifically supported) and human beings have caused it (not scientifically supported--we can only say that human action has contributed to the speed and magnitude of the ongoing change) and therefore human beings are bad (science cannot determine moral judgement).
The response on the other side seems to be something like this: We don't like the idea that we might be forced to change our economic system or way of life (science cannot evalute this) so therefore we reject the idea that the climate is changing (science does not support the conclusion).
My point here is that the debate is not actually a scientific debate. It is one in which scientific conclusions are either being used or rejected based on an a priori ideological stand. Is the debate over? That depends on how one defines what the debate is. There has never been any debate among earth scientists that climatic change is ongoing in earth history. There is no doubt among us that the earth has been warming over the past 10,000 years, since the end of the Wurm/Wisconsinin glaciation. There is a great deal of evidence that interglacial periods end with increasing global temperature means that create weather patterns that then cause renewed glacial advances. The preponderance of the evidence indicates that this time, the warming is happened faster and is greater than prior ends of interglacial periods. These results can be tied to increasing greenhouse gases in the atmosphere. And we can measure the effect of human activities that put a great deal of carbon dioxide into the atmosphere. In particular, we are burning fossil fuels at ever increasing rates which is releasing carbon dioxide that was previously sequestered in the regolith for the past 250 million years mas o menos. All of these things are within the realm of science to test and demonstrate.
What we cannot say for certain is what the consequences of this will be for human civilizations. Predictions can be made based on evidence from past interglacial periods and whole vast epochs when carbon dioxide was more abundant in the earth's atmosphere. But conditions are not exactly the same. As the remaining glacial ice from the Wurm/Wisconsinin melts, we can expect sea levels to rise. We can measure the volume of the ice and make some prediction of how much water would be added to our oceans. But we cannot say how fast this would happen and exactly what the human consequences would be. We can predict that weather will become more extreme, because the earth's oceans are essentially great heat engines that distribute that energy around the planet via weather. But we cannot say whether or not a specific weather event was caused by climate change. There is not one cause of weather--it is a stochastic system. Anyway, any event has a chain of causes, some immediate and some more ultimate. Finally, we have no idea how much impact small changes we can make in the earth's carbon budget would have on climate change. This is where the debate actually begins. Science can tell us what has happened, what is happening and how, and it can make predictions about consequences within a range of error. (In this case there are many variables and that range of error is rather large). Science cannot determine what, if anything, human beings should do about it. Science cannot properly make moral judgements about what the right actions would be. That is up to us as whole human beings who must balance knowledge across all human realms of knowledge: the physical, the moral and the spiritual.
As a scientist, I can say what the evidence tells us. And as a scientist, every conclusion I make must be stated within a range of error. But it is as a human being that I want to hold out some hope about climate change. One hundred and ten thousand years ago, the earth entered the last glacial advance (called the Wurm in Europe and the Wisconsinin in North America). The species Homo sapiens sapiens was around then. And during that glacial period, the human species underwent great adaptations that, by about 40,000 years ago, made us fully modern. The way our brains work, and many of the traits that arise from that, including modern cultural behavior (such as group organization and art) have been stable in the human population these last 40,000 years. We have much evidence of certain genetic polymorphisms (differences among individuals) that have been stable since this time. Change is continuous over time on this earth, and as a species, we certainly have the range of genetic variation to be able to adapt to change. And something more. In the past 40,000 years we have developed something unique for life on earth. Culture. And during the past 10,000 years we have developed something even more adaptable: Civilization. We are able to record and use information from our ancestors in order to expand our knowledge beyond that of a lifetime and now can adapt even more rapidly. Some of us call this way of passing on knowledge memes.
Even if the seas are rising my bet is that Homo sap sap has the memes to deal with it. And I wonder what people are doing about it now, while the ideologues argue? I don't have to be a betting woman for that. Individuals are moving forward even while governments wrangle and Al Gore refuses to reduce his carbon footprint. But neither 'gods nor governments' are getting it done. It is good old human ingenuity.
And it is this that gives me hope. Lots of it.
