Climate change will undoubtedly affect the water cycle in the Pacific Northwest.
- The most visible and direct effect of a warmer world on our region’s hydrological cycle will be on the snowpack. For basins whose winter snowpacks are historically near the melting point of water, such as those in Cascades, the consequences are greater: increased and more variable streamflow in winter, and decreased streamflow in late spring and summer.
- Climate change brings a propensity for more intense storms, increasing the likelihood of flooding. However, the magnitude of these changes may be small in comparison to natural variability and so our ability to detect the affect of climate change on storm intensity our observations is restricted.
- Climate change will also impact the how water moves from the land back to the atmosphere through evaporation and transpiration. However, the net effect of climate change on plant transpiration is difficult to anticipate because it depends not only on the changing atmospheric demand but also on how plants’ water use efficiency during photosynthesis responds to increasing CO2, how total vegetation cover will change, and how plant species distributions will be altered.