Medford and Jackson County Climate Projections

Summary:

A review of the historic climate trends and projections for Jackson County through the century assuming humanity continues the Business-as-Usual behavior of contributing increasing climate pollution to our atmosphere reveals that conditions by 2100 may approach an annual average nearly 10⁰F above the 1981-2010 baseline. Summers will likely warm more than the other seasons increasing evaporation. Precipitation will likely continue at the same overall annual average as historically with greater variability between wet and dry years. Winters will likely see an increase in precipitation with the summer dropping slightly and spring and fall declining marginally. The number of days annually over 100⁰F will likely rise, possibly reaching over 40 days by the end of the century. This will probably be accompanied by an increasing number of frost and freeze-free days and an expanded growing season though countered by reduced water availability during summer and fall.

Snowfall is expected to decline substantially during the century, dropping to near zero at lower elevations by its end with precipitation falling as rain at lower elevations rather than snow at higher elevations. The reduced snowpack, with its reduced water content will likely reduce stream flow during late summer and fall and reduce water availability downstream for domestic, commercial/industrial, recreation, and agricultural use. With reduced stream flow, waters will likely be warmer and contain less oxygen compromising the habitat for aquatic species. As the climate warms through summer with little or no increase in annual precipitation, evaporative deficit will climb and both soil and vegetation moisture will decrease.

Among an array of problems generated, this combination of future conditions will compromise health, and water supplies, and elevate the risk of both drought and wildfires spreading rapidly once ignited.

The Historic Average. Those discussing climatic conditions frequently relate current conditions and hopes for the future to some normal or historically average condition. If there is one lesson to be learned from a review of the trends and projections for Medford and Jackson County climatic variables it is that hoping that current harsh conditions will return to historic patterns are unreasonably optimistic. Rather than thinking of our future in terms of some historic ‘normal’ or ‘average’ condition we need to think in terms of the trends and what those trends indicate the future is likely to bring.

Medford and Jackson County Climate Trends and Projections The pdf file