Is our weather changing?

While there are always great uncertainties whenever making predictions about the future, most scientists support the idea that our climate is being affected by emissions of a number of "green house gases."  The most significant of these is carbon dioxide produced by our use of fossil fuels.   

Global warming cannot be modeled with precision and assessments on the scale of a region like the Pacific Northwest are even more uncertain.  However, it is possible to make general predictions about potential changes, and the Council is considering this information as a source of risk in its planning to assure the region an adequate, efficient, economical, and reliable power supply. Many factors and variables will also affect global warming:  how fast the global economy continues to grow and what kinds of energy sources are used to supply that growth. 

Atmospheric and ocean scientists remain uncertain about whether global warming would result in warmer and wetter conditions, or warmer and drier conditions in the Pacific Northwest. In a warmer and drier scenario, overall volume of water passing through the Columbia River Basin hydroelectric system would decrease relative to historic averages, thus increasing the cost to produce power. In a warmer and wetter scenario, the amount of precipitation would increase slightly in the long-term, potentially reducing the cost of power.
Temperature and precipitation changes will have major implications for the region’s river system, the Columbia and its tributaries. In either a warmer and drier or warmer and wetter case, the annual snowpack would decrease, resulting in higher river flows in winter and lower flows in summer. This could lead to many potential problems, from putting pressure on storage reservoirs and the risk of winter flooding, to jeopardizing fish survival — particularly salmon and steelhead — by reducing the ability of the river system to meet minimum flow and maximum temperature requirements during spring, summer, and fall migration. Other possible effects include:

• Boosting winter production of hydropower while Northwest demands are likely to drop due to higher average temperatures (a good thing for power);
• Reducing the size of the spring runoff and shifting its timing to slightly earlier in the year (potentially a bad thing for fish);
• Reducing late spring and summer river flows and causing average water temperatures to rise (a bad thing for fish);
• Reducing the ability of reservoirs to meet demands for irrigation water (a bad thing);
• Reducing summer power generation at hydroelectric dams when Northwest demands and power market values are likely to grow due to higher air conditioning needs in the Northwest and Southwest (a bad thing for revenues); and
• Affecting summer and fall recreation activities in reservoirs (a bad thing).

There are implications for the electricity industry, too. Current scientific knowledge holds that global warming largely results from increased production of carbon dioxide and other greenhouse gasses due to human activities. Because of the widespread use of fossil fuels to produce electricity, the electricity industry worldwide is a principal contributor to the growing atmospheric concentration of carbon dioxide and would be affected by any initiatives to reduce carbon emissions.

As part of its revision of the Northwest Power Plan, the Council is reviewing the status of the global climate change issue, including the current understanding of possible effects on the Northwest power system. The Council is using its planning model to look at projected climate change effects on the hydroelectric system and on the timing and magnitude of the electricity demands it has to meet. In addition, the model is being used to assess the potential effects of control policies aimed at reducing greenhouse gas emissions on the relative cost-effectiveness of resource choices available to the Northwest. This involves incorporating different scenarios about the probability, timing, and magnitude of carbon control measures like a carbon tax into the planning process. This analysis should also shed light on the value of other strategies to address climate change impacts. The power plan will include an assessment of how to minimize the risks posed by potential global climate change mitigation policies.