Shifting Baseline Syndrome and its Effect on Normalizing Increasingly Extreme Temperatures

September 26, 2022

Shifting Baseline Syndrome – it sounds like a medical problem, but it’s not.

It’s a term coined to describe the psychological and sociological changing of people’s thresholds of what is considered normal – or the “baseline” – in the absence of experience or information regarding what has occurred in the past. An article by Soga and Gaston in the journal Frontiers in Ecology and the Environment says that Shifting Baseline Syndrome (SBS) is “increasingly recognized as one of the fundamental obstacles to addressing a wide range of today’s global environmental issues.” Originally coined by oceanographers, global climate change also fits squarely into the scope of one of those global environmental issues.

A vast majority of people live in the “here and now” – in other words, their attention is focused on what is happening right now, in the place where they currently are. When related to the atmosphere, what is happening at the current time, in any given location, is weather. It is difficult for many to relate to climate – what has or will be happening on a long-term scale, and even harder to relate to climate on a global scale. Even without relating globally, when temperatures continue to get hotter in a single location, hotter temperatures become the normal in many people’s eyes so they have a difficult time perceiving their climate as warming.

Consider a case in point of the Pacific Northwest of the United States, which experienced one of the most impactful heat waves in record-keeping history in June 2021. Temperatures were 20-40° F above 1981-2020 averages, overnight low temperatures exceeded normal high temperatures in many locations, all-time record temperatures were broken multiple days in a row over a widespread area, and over 1400 deaths were linked to this heat wave. In Portland, Oregon alone, one of the hardest-hit areas from the heat wave in the United States, nearly 100 deaths were linked to the heat wave and the previous all-time record of 107° F was broken multiple days in a row with high temperatures of 108° F, 112° F, and 116° F.

In 2022, Portland did not see these exceptional high temperatures, but the summer again will finish as one of the hottest on record. This year, it was more about the frequency and duration of heat instead of the sheer intensity of a historic heat wave like last year. August 2022 in fact shattered the all-time hottest August on record by a full degree and a half, and the hottest month on record by about a full degree Fahrenheit. July 25-31 was the hottest week ever in Portland, and the entire July 25-August 31 period crushed the record for the previous hottest such time period by over 3 degrees. The combined July-August period was also the hottest on record. Possibly most frightening is that July 2022 broke the previous monthly record for the warmest average daily overnight low temperature, only for that to be broken by over a degree in August. In a land with less air conditioning than most of the United States – and a good proportion of elderly and others who have moved to the region because of the purported more mild climate – the increasing inability to cool down at night is increasing danger of heat-related illnesses and other issues. Even drought and wildfire concerns have cropped back up after a wetter La Niña spring – Portland hasn’t seen measurable rainfall since early July, the 3rd longest dry stretch on record as of September 1.

Most of these previous broken records have occurred since 2015. From 1941-1970, the first 30 years of observations at Portland, the average August temperature was 66.9° F. From 1993-2022, the most recent 30 years, the average August temperature was 70.6° F, an increase of nearly 4 F°. In 2022, the average August temperature was 75.1° F. 30-year average low temperatures in August have increased even more, from 55.5° F to 59.1° F (August 2022 was 62.9° F). The summer of 2022 has seen five days of 100° F or higher, tied with three other years, including 2021, with the most on record. It has also broken records for the greatest number of 99°+, 98°+, 97°+, 96°+, 94°+ and 93°+ days in one year, largely due to a persistent ridge over the West Coast as has been the case for most years since 2015. Of course, one year or even the past 8 years doesn’t constitute climate, but these temperatures are becoming much more normal in the Pacific Northwest.

Except for a few who have lived in the area long enough to remember the mid-20th century (less than half of the population of the Portland metropolitan area was even born in Oregon, let alone have lived in the area long enough and possess the ability to recall the weather from personal experience 50-70 years ago), the hot summers are normal for the region. Gone are the days when, in the mid-20th century, Portland averaged less than 10 days a year with high temperatures of at least 90°. Now Portland averages around 20 such days per year. Seattle’s average has also doubled, from 2 days per year of 90° or higher per year in 1945-1974 to over 4 per year from 1993-2022. Since 1995, Seattle has averaged 8 90-degree days per year over the past 8 years, including record breaking numbers of 90°+ days of 12 days in 2015, 11 days in 2018, and 12 days again in 2022. No other year before 2015 saw more than 9 in a single year dating back to 1945. In the mid-20th century, the Pacific Northwest was in fact the mild corner of the country where summer high temperatures averaged in the 70s and summer low temperatures in the low to mid 50s, and “nature’s air conditioning” as the locals call it, otherwise known as onshore flow from the Pacific Ocean, kept any hot days to a minimum and in only brief bursts. Those days are disappearing rapidly.

And while more urban development naturally increases temperatures at weather stations in urban areas, other weather stations in more rural areas exhibit signs of increasing temperatures as well at a lower rate, so the warming is real, with urban development increasing the urban heat island effect. Besides, where most people live in these urban areas are where the effects are felt by the most people, so it is still very important to look at changes in these urban observations.

There are other places around the country and the world that exhibit this same phenomenon. The Pacific Northwest was simply chosen because of the extremely historic recent 2021 heat wave and because it is one of the most vulnerable and unprepared regions in the U.S. for increasing heat as well as the region of the U.S. and even the world that appears to have the highest upward trend in summer temperatures and highest trend downward in summer precipitation.

But many local residents don’t necessarily feel the same way. Call it climate amnesia or being blind to what’s happened in the past, or before they remember or lived in the area. This is the new normal for the Pacific Northwest and many areas around the world, and for many, that’s what they know and accept as normal now. Climate researchers combed through over 2 billion posts on Twitter in the U.S. and found that although initially people will tweet about temperature extremes, even after just a year or two, people get “blind” to those new normal temperatures and stop posting about them. Even media outlets begin treating the heat as normal; after the historic 2021 heat wave, the frequency of temperatures in the 90s to near 100 in the Portland area in 2022 was not such a big deal to some, despite the record average temperatures and frequencies of this heat.

It’s enough to make one wonder – what would people’s reactions be if a place like Portland were to suddenly revert back to what used to be a normal summer in the mid-1900s, such as July-August 1943, which was very close to the 1941-1970 average. During those two months, there were more days with highs in the 60s (4) than in the 90s (3), with 91 being the highest temperature and 61 the highest low temperature. A few days even had low temperatures in the 40s. July 26, during the peak of the average hottest time of year, saw a high of 68. The coolest year on record, 1954, only saw three days above 80 during July and August, with 82 the highest temperature! – and 21 days with highs in the 60s. One can only imagine what residents nowadays would think of such weather in the summer.

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