Even the local weatherman, whose main job is to give a consensus five day forecast, feels the need to rail against "climate change skeptics" and talk about melting polar ice. Thanks for the intellectual stimulation. It is good, once in a while, to remind one's self what a good, measured and circumspect approach to science has to say about climate cycles. Professor Judith Curry, Chair of the Department of Earth and Atmospheric Sciences at the Georgia Institute of Technology, is a scientist whose writings I've come to enjoy.
Starting from the beginning, she notes the large number of degrees of freedom in a complex natural system that encompasses immense atmospheric and oceanic systems. These in turn, are driven by a number of complex sub-systems with innumerable inter-linkages. Finally, these systems are non-linear and regularly feature large scale perturbations. It sounds simple, but look how different it is to situations in which traditional mathematical models do well.
Modelers like to characterize systems with an economy of sub-systems, and these in turn are preferably characterized by limited numbers of well defined linkages. Even if the system is thought to be non-linear, it's nice to use linear approximations. It's also nice to have the system converge quickly to a new equilibrium after a small perturbation. Whether it's a model of an ocean fishery or a model of central bank monetary intervention, modelers don't like to begin with the complexity of natural systems because of the need for circumspection about any theoretical results.
High priests of climate change have no doubts, qualms, or reservations. Thus for example, the American Meteorological Society, of which Dr. Curry is a former member of the Executive Council, writes,
- "Warming of the climate system now is unequivocal, according to many different kinds of evidence.
- Climate is always changing. However, many of the observed changes noted above are beyond what can be explained by the natural variability of the climate. It is clear from extensive scientific evidence that the dominant cause of the rapid change in climate of the past half century is human-induced increases in the amount of atmospheric greenhouse gases, including carbon dioxide (CO2), chlorofluorocarbons, methane, and nitrous oxide.
I have always been fortunate to have had really good teachers of physics, chemistry, mathematics, geology, and oceanography during my academic and professional careers; none of them ever spoke or wrote like the AMS above. They always respected the limitations of what they knew or had measured; they were always cognizant of their own ignorance of important matters, which were always the subject of further research.
But, as the AMS categorically states on behalf of its large membership, "case closed" for anthropogenic climate change.
How we got to where we are today can be explained in large part by the "framing" of the issue. The UN Framework Convention for Climate Change framed the issue in terms of dangerous climate change which supposedly could be directly mitigated by stabilizing carbon dioxide levels at arbitrary levels. The allocation of the global mitigation burden would be done through an intensely non-scientific, arbitrary political procedure.
Scientists in these kinds of settings become tools of the politicians and NGO policy wonks, and they also become slaves to their own personal ambitions for prestigious awards, research grants, endowed chairs, and for joining the well-paid international speaker's circuit on all things green.
I am getting to know the work of Dr. Curry and many of her colleagues, but I have always been impressed by a 2009 document from the Geological Science Committee of the Polish Academy of Sciences on the Threat of Global Warming. It struck the right tone for my ears, not dissimilar to that of Dr. Curry. (The translation from Polish has some English malapropisms, but a reader can suspect where they occur and substitute a better word.) Here are some excerpts,
- Geologic research proves irrefutably that the permanent change is the fundamental characteristic of the Earth's climate as throughout its entire history, and the changes occur in cycles of varied length - from several thousand to just a few years.
- Not all reasons for climate change or their phenomena are fully known yet.
- Although in the history of the Earth, a considerably warmer climate than today had dominated, there had been repeated occurrences when the Earth experienced massive global cooling which always resulted in vast ice sheets that sometimes even reached the subtropics.
- Over the past 400 thousand years - even without human intervention - the level of CO2 in the air, based on the Antarctic ice cores, has already been similar 4 times, and even higher than the current value. At the end of the last ice age, within a time of a few hundred years, the average annual temperature changed over the globe several times; in total, it has gone up by almost 10 °C in the northern hemisphere, therefore the changes mentioned above were incomparably more dramatic than the changes reported today.
- Detailed monitoring of climate parameters has been carried out for slightly over 200 years; it only covers parts of the continents, which constitute only 28% of the world. Some of the older measuring stations established - as a result of progressive urbanization, in the peripheries of the cities, are now within them. This factor, among other things, is the reason for the rise of the measured values of temperature. The research of the vast areas of the oceans has only been launched 40 years ago. Measurements taken for this kind of short periods of time can not be considered as a firm basis for creating fully reliable models of thermal changes on the surface of the Earth, and their accuracy is difficult to verify. That is why far reaching restraint needs to be kept regarding blaming, or even giving the biggest credit to man for the increased level of emissions of greenhouse gases, for such a theory has not been proven.
- There is no doubt that a certain part of the rise of the level of greenhouse gases, specifically CO2, is associated with human activity therefore, steps should be taken to reduce the amount on the basis of the principles of sustainable development, a cease (sic.) of extensive deforestation, particularly in tropical regions.
China certainly lags behind the developed economies and behind many emerging nations in the magnitude of air pollution from burning coal and from inefficient transportation systems. Mitigating their large incremental role in total CO2 emissions is not high on their list of national policy objectives. India's black soot-spewing diesel trucks and public buses have created London fogs for many decades in cities like Calcutta; huge public health issues have been created for women, children and the elderly from ingesting black carbon soot into lungs and nasal passages. India too doesn't see nationwide fleet replacement as a viable economic alternative for mitigating climate change. Brazil has cleared wide swaths of the Amazon rain forest, which removes natural balancing mechanisms for higher fossil fuel use in growing cities. Russia's air, water and soil problems are well known, but President Obama is not going to lecture President Putin on the need to buy into climate change.
So, we use climate change as another political litmus test for our own political righteousness, which is defined by politicians from Al Gore to Mike Bloomberg. Scientists should remove themselves from this game and refuse to accede to demands of politicians for slogans ("glacial melt," "acid oceans," "rising sea levels") and certainty based on pseudo-science.
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