For those who still doubt climate change, and there are many, it seems appropriate to note that scientists studying climate change, about 97% of them, agree that human activity is definitely having an impact on the planet’s climate.
How can they come to such a conclusion so definite? Perhaps the simplest method of all, the process of elimination, has led climate-change scientists to agree that human beings are the cause of the problem that we’re now experiencing, and is only expected to get worse. How did scientists eliminate other causes from the climate-change model?
Dr. Benjamin Santer has published a paper, entitled “Human and Natural Influences on the Changing Thermal Structure of the Atmosphere,” explains how variables in the natural world, including human activity, have an affect on the atmosphere and climate change. By comparing satellite observations to the output of twenty different climate-change models, Santer and other scientists were able to determine which variables impact, and how they impact, the climate.
There were basically three series of tests, depicting different scenarios. One test run of the climate models included only natural effects of sun, wind, volcanoes, and others, but without human activity. A second test run included only human activity without these natural effects. A kind of fingerprint, attributable to one or the other, that is, natural or human, can be seen in the patterns that emerge. A third test run was a comparison of the natural, human, and observed climate-change data.
The observation was clear, that certain patterns, the fingerprint, matched that of the data obtained from the human-activity. Other patterns within the satellite and ground observations matched the fingerprint of the natural-world climate-change model. The conclusion is, “human-caused latitude/altitude pattern of atmospheric temperature change can be identified with high statistical confidence in satellite data. Results are robust to current uncertainties in models and observations … Our results provide clear evidence for a discernible human influence on the thermal structure of the atmosphere.”
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