For some reason, I don't find it surprising that Oregon is a hotbed of climate alarmism. Thus, when the Portland Tribune recently published an article describing how Oregon's “warmer climate imperils our health,” it seemed appropriate to look further into the claims being made.

Apparently, climate change in Oregon will lead to “less snow on Mount Hood? [but] we can live with that.” Interesting, given how there has been no significant trend in maximum overwinter snowpack on Mount Hood since records began in 1981. Indeed, according to an article in 2012 at ABC News Cleveland, snowpack in the Cascade Mountains has been increasing since the mid-1970s.

The Tribune's article references the latest “Oregon Climate and Health Profile Report” produced by the Public Health Division of the Oregon Health Authority. I found this document most illuminating.

We can take a number of statements in the Oregon climate and health report and examine them individually.

Claim: “Summers are getting hotter and drier.” There has been no significant decline in Oregon's summertime precipitation since records began in 1895. In fact, the correlation is positive towards increasing summertime precipitation, not declining.

Claim: “The last freeze of winter is occurring earlier, while the first freeze of fall is starting later... Similarly, the freeze-free season is expected to lengthen throughout the region. The largest changes are projected in northwest Oregon and the southern coast, both of which are expected to see an increase of more than 40 freeze-free days.” The historical climate trends on this subject (i.e., length of the growing/freeze-free season) are not as simple as this quote makes it sound. The following table shows the trends in length of the freeze-free season throughout Oregon since records began, and over the past three decades.

There are equal numbers of regions in the state having statistically significant trends towards lengthening (i.e., warming climate) and shortening (i.e., cooling climate) growing seasons. Over the last three decades, it is a similar tie with one each for regions with their growing seasons becoming longer and shorter, respectively. But more of the climate regions have correlations over the past 30 years towards shorter -- not longer -- freeze-free seasons.

As the table above also shows, the Pendleton climate region has seen an overall trend towards a longer growing season since records began back in 1893, but the trend over the past three decades has been the opposite -- towards a shorter growing season. A look at the actual data provides some useful insights, and nicely exemplifies why broad generalizations regarding climate change in the state are difficult to make with any reasonable degree of confidence.

Between the 1890s and 1940s, there was a substantial lengthening of the growing season in this region of Oregon. But since the 1940s, the growing season has gotten much shorter -- even appearing to accelerate in the shortening over the past several decades. Yes, overall since the 1890s the trend has been towards a longer growing season. But even a superficial look at the data tells us this is not the full story with regard to purported anthropogenic climate change impacts.

All of the increase in the frost-free season length took place prior to the 1950s, when anthropogenic greenhouse gas emissions were negligible. Since the 1940s, as man-made GHG emissions have accelerated, the length of the growing season has accelerated in the opposite direction to what the alarmists would expect. Good luck explaining this time series of data within the context of AGW theory, and thus, generalizations about Oregon's climate break down when we get into the raw data. The devil is always in the details for good science.

Claim: “By mid-century, much of Oregon is projected to have 20 fewer days below freezing per year... A large decrease in the annual number of freezing days <0 C (<32 F) is expected throughout most of the Northwest. The Northwest is projected to have a decrease of 35 freezing days. Except for coastal areas, most of Oregon is projected to experience at least 20 fewer days below freezing, with higher elevation areas in the Cascades experiencing more than 40 fewer freezing days.”

Well, according to the data, there are more regions of Oregon with an increasing -- rather than decreasing -- number of freezing days since records began. Even over the last three decades, the only statistically significant trend is one towards more -- not fewer -- freezing days, and the correlations are split about evenly around cooling versus warming trends.

This would be another dataset that fails climate generalizations. For most of Oregon, there are still more freezing days each year -- on average -- than there were a century or more ago, and for much of the state the number of freezing days are still increasing.

Claim: “Extreme cold <-12.2 C (<10 F) is expected to diminish. While western parts of Oregon will experience little change, much of southeastern Oregon will experience 10 to 15 fewer days of extreme cold per year during the period of 2041-2070.” Over the last three decades, none of the state's climate sub-regions have seen a significant change in the number of extreme cold days each year. Since records began, one region has a significant decline, one has a significant increase, and the remaining five regions have no significant trends. Overall, this looks like an absence of a crisis as well.

Claim: “One measure of extreme precipitation is the number of days per year with precipitation exceeding 1 inch. For most of Oregon, models of scenario A2 indicate that changes in days with more than 1 inch of precipitation will be less than normal year-to-year variation. There is greater confidence in projections for central and northeastern Oregon, which show an increase of more than 40% in the number of days per year with precipitation exceeding 1 inch. Findings suggest that southeastern Oregon will experience an increase of approximately 15% days per year with precipitation of more than 1 inch.”

Since records began, only one climate region (the Eugene area) has seen a significant increase in the number of days per year with more than 1 inch of precipitation. Another region (the Astoria area) has experienced a significant decline. The other five regions have no significant trends since records began. During the last three decades, the only significant trends have been two climate regions of the state with significant declining trends in number of days with “extreme precipitation.” The remainder of the state has no significant trend. Overall, it does not appear that such “extreme precipitation” events are increasing in the state, particularly in recent decades.

Claim: “Oregon is likely to experience more extreme events like heat waves... Extreme heat days/nights will likely increase.” Only the small Burns climate sub-region in the southeastern part of the state has a significant trend towards “extreme heat days” (>95 F) over the last three decades. The rest of the state has seen no increase in the numbers of extreme heat days over this time frame -- on the contrary, much of the state has negative correlations towards fewer extreme heat days.

On a lighter note, the Oregon climate and health report states that “in Oregon, about 6 percent of the population speaks English less than very well,” which itself seems grammatically problematic. As well, under the “Causal Pathways” section of the report, which describes the “direct and indirect correspondence between projected climate exposures and health outcomes,” there is this gem:

“Recreational swimming in Oregon is not without risk for those seeking relief from heat. Most drowning deaths occur during the heat of summer months and drowning deaths in cold-running rivers fed by snow melt can be frequent. Cold shock from entering water below 70 F can cause involuntary gasping, severe hyperventilation and severe cardiac stress. Increased heat events could lead to more people entering hazardously cold waters that contribute to drowning deaths.”

So, in other words, anthropogenic global warming will lead to more heat events during the summer in Oregon, and in response, members of the public will be led to jump into ice-cold rivers in a desperate attempt to cool off, and will subsequently drown? OK then, although I will confess I experienced “involuntary gasping, severe hyperventilation and severe cardiac stress” from reading Oregon's climate and health report. Perhaps having to read the climate reporting is the real public health risk from climate change.