HO-82-04-2 -- Urban Climate Modification PDF

Climate is changing and there is measurable increased variation during the present climate transition. Whether global climate change is presently occurring due to overall long-term cooling or warming remains debatable, until sufficient measured data are accumulated to place the change into the realm of recorded past history and thereby are verified in the usual climatological manner. The initial concern over natural global climate variation placed the earth at a peak in temperature during the early 1940s. Due to variations in the orbital eccentricity of the earth, its distance from the sun was increasing therefore resulting in an overall cooling (on the order of about one degree per 500 years).

Urbanization occurring at accelerated rates in both developed and lesser developed countries contributed to unnatural variation in the trend of global temperature change. Through the decade of the 70s, it was argued that the portion Of C02 in the atmosphere from the burning of fossil fuels was increasing "the greenhouse effect", causing the air temperature to rise. Contrary to this contention, the increased turbidity of the atmosphere related to increased suspended particulates--a phenomenon associated with the algomeration of animals into herds and humans through urbanization--was thought to cause increased global cooling by contributing to increases in the reflection of incident solar radiation.

The concensus of scientists a few years ago was that the anthropogenic effects were cancelling each other and the earth was following a natural cooling trend. A recent study by a space scientist refers to evidence of global temperature increase due to fossil fuel (coal, oil, and gas) and wood burning. The impact of this warming is greater than was originally predicted for the 21st century. However, predictions of continued warming remain speculative and conditional upon the continued flagrant practices of forest (clearcutting) stripcutting and the excessive burning of wood and fossil fuels. Variation associated with climate change continues to increase.