release and substantial variations in global circulation patterns for extremely large heat releases. However, the simulations represented extreme cases, and the ability of models to give statistically significant results for more realistic experiments is currently limited. It is possible that the magnitude of heat release impacts is dependent on the season. During the winter, when more stable atmospheric conditions prevail, the impacts of waste heat occur mainly in the boundary layer and have a larger impact on surface temperature. In the summer, an increased vertical mixing of the excess heat and a smaller perturbation of surface temperature is likely. Thermal pollution cannot be examined in isolation when one is considering global climate changes.® Certainly, other climate-forcing parameters play important roles. Carbon dioxide and atmospheric aerosols will be discussed later in this report, and natural climatic fluctuations must also be taken into account. In addition, it is not possible to calculate reliably an atmospheric temperature increase due to added heat without considering the total response of the atmosphere and potential feedback mechanisms. For example, if the surface temperature increases because of heat added to the atmosphere, evaporation will increase, and this could lead to increased global cloudiness. The clouds could provide negative feedback by reflecting more incoming solar radiation into space. On the other hand, a warming of the earth's surface could result in a decrease of surface albedo due to melting of snow and ice cover. This would lead to increased surface absorption of solar radiation and enhance the warming trend. It is not clear from current knowledge whether anthropogenic heat rejection at any time in the future will significantly alter global climate. It can be said with reasonable confidence that significant global impacts from waste heat are unlikely in the next 50 to 100 years. Beyond that time frame, if energy use continues to grow, global impacts of a noticeable, if not substantial, magnitude are possible. 2.1.3 Regional Impacts Although it is apparent that man's worldwide energy release is not particularly large in comparison to the incoming solar flux, this is not
RkJQdWJsaXNoZXIy MTU5NjU0Mg==