Precision on climate change figures
The Prime Numbers column of the Sept. 2 issue included a factoid sourced to Reuters stating that the researchers for the Intergovernmental Panel on Climate Change are 95 percent certain that "half of Earth's global warming is caused by human emission of greenhouse gases." This is a rather casual generalization, since there is no time frame given for "Earth's global warming" over which the factor of one-half is calculated.
I suspect that the time frame implied is the last century or so, with an average global temperature rise of about 1.5 to 2 degrees F., and it is certainly plausible that half of that rise can be traced to human activity. However, this is not the whole story: Earth has gone through multiple warming and cooling cycles over geologic time scales. The warming phase of the latest cycle started about 20,000 years ago. Based upon Antarctic ice-core data, the temperature rise between that time and the present is about 15 degrees F.
The same data also indicate that the temperature rise in the Antarctic over the past 200 years (roughly corresponding to the start of the Industrial Revolution) is about 0.5 degrees F. Thus, over the full geologic warming cycle, only about 3 percent of the Antarctic temperature rise occurs during the period of large-scale human burning of fossil fuels. Climate change is a complex subject and the "facts" about it must be stated precisely.
Steven K. Brierley
Interpreting truth in the Quran
I read Emran El-Badawi's Sept. 2 commentary "Muslims should welcome fresh take on prophet's sayings" with great interest.
In praising a new seven-volume revision of the Muslim Hadith, Mr. El-Badawi seems to say that sharia (Islamic law) and the Quran should not be taken literally but should be interpreted according to the values of modern society. Does this mean that we should interpret the Quran according to the spirit of our time? And does this mean that truth has no universal quality, but instead a temporary one?
Angelo A. De Gennaro