of the water it uses to backwash itself. This waste has a significant impact on groundwater lev- els and drinking water availability. For example, in arid regions such as Arizona, such waste is part of the cause of extremely low groundwater levels.
What about Weather Extremes?
Although an increase in average global temperature of 1ºC might not have a great impact on the energy bills of many preservation institutions, its effects on their disaster plans and cata- strophic insurance costs will be a major concern. Hurricane Katrina was only a warning to us— there is more to come. Extreme weather changes caused by global warming are the most seri- ous concern for all institutions, no matter where in the world they are located. We have only begun to see the might of destruction in regions known for their weather-related high risk. What will happen in these high-risk regions as their populations continue to expand? An in- crease in extremes of weather is far more dangerous to our historic infrastructure than is a small ambient temperature increase.
A Slow but Good Start
A new movement in sustainability has begun. We are now encouraging clients to go green, and they are, slowly but surely. Geo-exchange projects are becoming very popular, and pho- tovoltaic electric power is right behind. We are now using gray water for reuse—a practice that was a code violation not long ago. New HVAC energy saving techniques are now the norm; they incorporate hot refrigerant gas reheat, heat recovery, variable speed controls, and many more features. The agencies endorsing this movement include the Environmental Pro- tection Agency, in their Energy Star program; various utility companies; and the U.S. Green Building Council, in their Leadership in Energy and Environmental Design (LEED) program.
Conrad Climate Control Systems Design and Climate Change Contribution to the Experts’ Roundtable on Sustainable Climate Management Strategies, held in April 2007, in Tenerife, Spain