The Earth is warming but the cause is unknown
Scientists in this section accept the observations of rising temperatures, but conclude it is too early to ascribe any cause to these changes, man-made or natural.
* Richard Lindzen, MIT meteorology professor and member of the National Academy of Sciences: "We are quite confident that [the] global mean temperature is about 0.5 degrees Celsius higher than it was a century ago… [but] we are not in a position to confidently attribute past climate change to carbon dioxide or to forecast what the climate will be in the future..." [1]. He has also said "Indeed, if all else were kept equal, the increase in carbon dioxide should have led to somewhat more warming than has been observed." [2] (Also in WSJ, June 26, 2006, Page A14)
* Robert C. Balling, Jr., director of the Office of Climatology and an associate professor of geography at Arizona State University: "[I]t is very likely that the recent upward trend [in global surface temperature] is very real and that the upward signal is greater than any noise introduced from uncertainties in the record. However, the general error is most likely to be in the warming direction, with a maximum possible (though unlikely) value of 0.3°C. ... At this moment in time we know only that: (1) Global surface temperatures have risen in recent decades. (2) Mid-tropospheric temperatures have warmed little over the same period. (3) This difference is not consistent with predictions from numerical climate models.", George C. Marshall Institute, Policy Outlook, September 2003 [3]
* Roy Spencer, principal research scientist, University of Alabama in Huntsville: "We need to find out how much of the warming we are seeing could be due to mankind, because I still maintain we have no idea how much you can attribute to mankind.", George C. Marshall Institute, WASHINGTON ROUNDTABLE ON SCIENCE & PUBLIC POLICY, Satellite Temperature Data, March 2006 [4]
* Jan Veizer, Ottawa-Carleton Geoscience Centre, University of Ottawa, Ottawa, K1N 6N5 Canada & Institute for Geology, Mineralogy and Geophysic, Ruhr-Universität Bochum, Germany: "The standard explanation for vagaries of our climate, championed by the IPCC (Intergovernmental Panel on Climate Change), is that greenhouse gases, particularly carbon dioxide, are its principal driver. Recently, an alternative model that the sun is the principal driver was revived by a host of empirical observations. Neither atmospheric carbon dioxide nor solar variability can alone explain the magnitude of the observed temperature increase over the last century of about 0.6°C." ... "In summary, the above empirical observations on all time scales point to celestial phenomena as the principal driver of climate, with greenhouse gases acting only as potential amplifiers."(Geoscience Canada, March 2005) [5]
[edit] The Earth is warming but mostly due to natural processes
Scientists in this section accept the observations of rising temperature, but conclude that natural causes may be more to blame than human activities.
* William M. Gray, Colorado State University: "This small warming is likely a result of the natural alterations in global ocean currents which are driven by ocean salinity variations. Ocean circulation variations are as yet little understood. Human kind has little or nothing to do with the recent temperature changes. We are not that influential." Dr. Gray, who has worked in the field for 50 years, has labeled global warming "one of the greatest hoaxes ever perpetrated on the American people." [6][7]
* Willie Soon, Harvard-Smithsonian Center for Astrophysics: "[T]here's increasingly strong evidence that previous research conclusions, including those of the United Nations and the United States government concerning 20th century warming, may have been biased by underestimation of natural climate variations. The bottom line is that if these variations are indeed proven true, then, yes, natural climate fluctuations could be a dominant factor in the recent warming. In other words, natural factors could be more important than previously assumed.", Harvard University Gazette, 24. April 2003 [8]
* Sallie Baliunas, Harvard-Smithsonian Center for Astrophysics: "[T]he recent warming trend in the surface temperature record cannot be caused by the increase of human-made greenhouse gases in the air". [9] In 2003 Baliunas and Soon wrote that "there is no reliable evidence for increased severity or frequency of storms, droughts, or floods that can be related to the air’s increased greenhouse gas content." [10]
* Frederick Seitz, retired, former solid-state physicist, former president of the National Academy of Sciences: "So we see that the scientific facts indicate that all the temperature changes observed in the last 100 years were largely natural changes and were not caused by carbon dioxide produced in human activities.", Enviroment News, 2001 [11]
* Nir Shaviv, astrophysicist at the Hebrew University of Jerusalem: "[T]he truth is probably somewhere in between [the common view and that of skeptics], with natural causes probably being more important over the past century, whereas anthropogenic causes will probably be more dominant over the next century. ... [A]bout 2/3's (give or take a third or so) of the warming [over the past century] should be attributed to increased solar activity and the remaining to anthropogenic causes." His opinion is based on some proxies of solar activity over the past few centuries. [12]
* Fred Singer, Professor emeritus of Environmental Sciences at the University of Virginia: "The greenhouse effect is real. However, the effect is minute, insignificant, and very difficult to detect." (Christian Science Monitor, April 22, 2005) [13] "The Earth currently is experiencing a warming trend, but there is scientific evidence that human activities have little to do with it.", NCPA Study No. 279, Sep. 2005 [14].
* Robert M. Carter, researcher at the Marine Geophysical Laboratory at James Cook University in Australia: "The essence of the issue is this. Climate changes naturally all the time, partly in predictable cycles, and partly in unpredictable shorter rhythms and rapid episodic shifts, some of the causes of which remain unknown." [15]
* Tim Patterson [16], paleoclimatologist and Professor of Geology at Carleton University in Canada: "There is no meaningful correlation between CO2 levels and Earth's temperature over this [geologic] time frame. In fact, when CO2 levels were over ten times higher than they are now, about 450 million years ago, the planet was in the depths of the absolute coldest period in the last half billion years. On the basis of this evidence, how could anyone still believe that the recent relatively small increase in CO2 levels would be the major cause of the past century's modest warming?" [17]
* Jan Veizer, Professor Emeritus, University of Ottawa: "At this stage, two scenarios of potential human impact on climate appear feasible: (1) the standard IPCC model that advocates the leading role of greenhouse gases, particularly of CO2, and (2) the alternative model that argues for celestial phenomena as the principal climate driver. ... Models and empirical observations are both indispensable tools of science, yet when discrepancies arise, observations should carry greater weight than theory. If so, the multitude of empirical observations favours celestial phenomena as the most important driver of terrestrial climate on most time scales, but time will be the final judge." (In J. Veizer, "Celestial climate driver: a perspective from four billion years of the carbon cycle", Geoscience Canada, March, 2005. [18])
* Marcel Leroux, former Professor of Climatology, Université Jean Moulin: "The possible causes, then, of climate change are: well-established orbital parameters on the palaeoclimatic scale, ... solar activity, ...; volcanism ...; and far at the rear, the greenhouse effect, and in particular that caused by water vapor, the extent of its influence being unknown. These factors are working together all the time, and it seems difficult to unravel the relative importance of their respective influences upon climatic evolution. Equally, it is tendentious to highlight the anthropic factor, which is, clearly, the least credible among all those previously mentioned." (M. Leroux, Global Warming - Myth or Reality?, 2005, p. 120 [19]) |
