As of Monday, 6-December I received extra credit assignments from 13 students. The average grade was 6/10. A student with the average score gets 6 extra points added to their course total.

In general, most students had closely read the article, and understood it to predict that, because of climate changes which probably result from increased emissions of CO2 into the atmosphere, future winters will see less snowpack development and more rain while summers will be drier (increased chance of drought). As snowpack is the major form of water storage for summer months, summer river flows will be diminished, water temperatures will be higher, and Pacific Northwest inhabitants, fish and crops will suffer. Further, the cited climate models predict broader seasonal variations in temperature and precipitation, and a higher incidence of flooding during winter monthgs.

The majority of student assignments focussed on (and took issue with) the report's recommendations for ways to prepare. The recommendations included ways to alleviate summer water shortages, impacts on salmon runs and forests, and preparations to reduce the effects of increased coastline erosion. This list of recommendations was condemned as too general, too naive and, in some cases, decidedly insufficient.

When I read the article, a few things struck me immediately regarding the science on which the study was based.

1. On page 3 (Climate change in the PNW) the authors speak of an observed "average trend in temperature of 1.4 degrees (C) per century." Figure 5, summarizing climate model studies, predicts an average rise in temperature of about 4 degrees (C) during the next 1/2-century. Even allowing for future increases in population, CO2 production per capita, and exponentially-increasing CO2 concentrations in the atmosphere, I find that sort of predicted rise in PNW average temperatures a bit hard to swallow.

2. The capability of the cited climate models to predict seasonal trends in temperature is given in Figure 6. I question that the model shown has done a very good job of "predicting" seasonal temperature fluxuations during the past century. At the very least, the authors could have quantified further how well their chosen climate model can predict future seasonal variations. The entire study is based upon this capability.

3. Clearly the authors of this report had to make compromises between completeness and accessibility in writing this 12-page summary of a much larger study. Writing such a summary is always very difficult, and the author(s) may have decided that supporting details about the modeling process would have just clouded the picture. Even though the article was very well written (for what it was), my and your own reactions to it serve to point out how difficult it is for the general public to appreciate and react to climate change studies.

I will now go explore the entire study in more detail and report back to this page. To me, the crux of the biscuit (to quote Frank Zappa) is the climate model(s) on which this study has been based.

Thank you all who participated in this project. I hope that you continue to seek out answers and question assumptions in your work to improve our collective future.

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