INTRODUCTION
As long as humans have been on Earth, they have been adapting to changes in regional climates. A regional climate is the average of the weather for a relatively long period of time, usually 30+ years, at a particular location on the planet. The natural periodicity of prolonged regional weather variations has been documented in various ways by humans for eons. For a comparison of human civilization in the northern hemisphere to Greenland ice core temperatures for the last 18,000 years see here. Some of the means of documenting changes in long term weather patterns, i.e. climate change, include crude prehistoric cave drawings of the animals and plants, paintings of frozen rivers (see Figure 1 of ice skating on the River Thames in 1684), and archaeological digs. There are also written records of climatic conditions as early as 5,000 years ago, perhaps even earlier. Ice, subsea, peat and lake bed cores are also used, for a more detailed discussion of the methods used see here and the links therein.
Most geologists agree that we are currently in an extended ice age. Technically we are in an “icehouse” condition (see here). When ice caps exist on one or more poles year-round for an extended period of time, the Earth is said to be in an icehouse. Global temperature may decrease further if the solar activity remains at its current low level (see here). But geologists deal in massive time increments of thousands, millions even billions of years. The general public makes its observations in decades, perhaps a generation and maybe even in a century, but not much more than that. Such a myopic view of the Earth’s climate can be misleading.
CLIMATE SCIENCE
Climate science is a combination of many scientific specialties such as geology, geophysics, astrophysics, meteorology, and ecology just to name a few of the larger branches. Some of these scientists are working to develop computer models of the climate using atmospheric physics, chemistry, actual data, proxy data, empirical variables and assumed constants. The models include statistical tools to present the results in the form of projections of measurable parameters, one of these is the global mean temperature. These projections are presented in time increments that mean something to the public. Dr. Judith Curry has written a good overview of computer climate modeling that can be downloaded here.
To gain an understanding of the regional climate that preceded humankind, we have to get creative. That means using proxies to determine the average temperature and perhaps life conditions in earlier years. The two most cited proxies are ice cores and tree rings, but there are other lesser known proxies. In addition, we can also make reasonable assumptions about the prehistorical past with observations of regional geology. For example, glacier movements are revealed by the scars and strange debris fields that are left with each glacial expansion and retreat. Great boulders are left in the middle of grassy plains as glaciers melt. Gravel placed by high velocity melt water rivers can even reveal the dynamics involved, perhaps even provide a timetable for the events. These points are made just to illustrate the importance of the geological perspective in understanding why the climate changes. It is, after all, the physical record.
Many scientists, across many disciplines, have made their career goals the understanding of these worldly and sometimes outer-worldly events. Some of these scientists have developed hypotheses that they defend with great vigor which is, of course, understandable. There is peer admiration, public recognition and research funding available when one’s hypotheses prove to be correct. But there is a danger in pushing any hypothesis beyond its limits. And that may be the case of the proponents of the singular CO2 driven global warming hypothesis.
THE DISAGREEMENT
The Deliberate Corrupt... Best Price: $13.74 Buy New $16.64 (as of 11:20 UTC - Details) Instead of following more traditional methods of analyzing data acquired through research, noting some phenomenon, developing an hypothesis that might explain the phenomenon, then publishing the research and the scientific conclusions to get the scrutiny of peers in that particular field of research, the CO2 warming proponents appear to have started with an hypothesis. The hypothesis was that “humankind’s accelerated use of fossil fuels had led to an increase in average global temperature by adding more CO2 to the atmosphere and enhancing the Green House Gas effect.” This is easily seen in the stated objective of the United nations Framework Convention on Climate Change (UNFCCC):
“UNFCCC’s ultimate objective is to achieve the stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous interference with the climate system.” (link)
In other words, they assumed that stabilizing the atmospheric greenhouse gas concentration would prevent climate change, they did not prove this assertion first. The previous hypothesis had been that aerosols would cause a cooling of the average global temperature and lead to a new massive glacial advance or “Ice Age.” The media sometimes calls a major glacial advance an “ice age,” but we are already in an ice age and have been for millions of years. Some say the new ice age predictions in the 1970s were in the minority and erroneous. They claim there was no consensus on global cooling (link). Others say there was a consensus (link). Then the impact of chlorofluorohydrocarbons (CFCs) on the ozone layer became the new major focus. A damaged ozone layer could increase solar radiation and lead to more cancer, animal blindness and plant withering (link).
Consensus among scientists means nothing. Proposing that a consensus exists by distilling published papers means absolutely nothing. Getting scientists together for an open discussion, presenting one’s hypothesis, showing the proof, then having a robust debate followed by an open show of hands may be a better way to define a scientific consensus, but even that could be biased by the quality of the presentations and the presenters involved.