Earlier this year Wawa-News published a letter of mine on the subject of pipelines, the economy and climate change. My letter was intended to make the case that as we try to create vibrant local, regional and national economies we cannot ignore the growing threat of climate change.
I referred to declines in Lake Superior ice cover, even knowing that this year would be a good year for ice. This seems to have been confusing for those who have not had the privilege to study climate change as thoroughly as I have. So I have prepared a series of short, approachable articles on how to begin thinking about climate change. This will then transition into some articles about why we should care, and what we might do here in Wawa and beyond.
There are a few principles upon which all useful thinking about climate change is built. The next three articles will cover one principle each. Here is the first:
Climate is not limited to what is happening locally, or even regionally, nor is it limited to what is happening right now. Understanding how the climate is changing requires both a broad geographical perspective and that we think across longer time periods.
The classic common sense response to claims about a warming Earth is “well it’s plenty cold outside right now,” or, “there sure was a lot of ice on the lake this year.”
It’s always a good idea to use common sense, as long as you remember that common sense can also be wrong. It used to be common sense that the earth was stationary and that the sun revolved around us; after all the sun moves through the sky, and it doesn’t feel like we’re moving at all! Science has been so revolutionary, because it sometimes undermines common sense, and in doing so drastically reshapes our understanding of the universe. If we don’t remember that common sense can be wrong, that things can be other than what they immediately seem, we become narrow-minded. Narrow mindedness is the opposite of the sort of thinking required to grasp climate change, as well as pretty much anything else in this world.
Wawa has experienced some very cold winters since 2015, and it has been a cold spring by recent standards (I will discuss why in a later article; for now it is enough to say that it is due to rapid changes in the arctic), but the long term trend has seen both an increase in average temperature, and a decrease in the number of days reaching -20 degrees Celsius or below each winter. Over the last decade, the earth as a whole has warmed approximately 0.4 degrees Celsius. That might not sound like a lot, but it is, as will become clear throughout this series of articles.
A warming planet does not mean that there aren’t still cold temperatures; as we all know it still gets plenty cold here in Wawa. In fact, it doesn’t even mean that there aren’t still record cold temperatures. But, as common sense tells us, if the earth is warming (and there is no question that it is), we should see more record hot days than record cold days.
That is exactly what we find when we take a broad perspective. Across the earth in 2018, 66,809 daily record highs (the highest temperature ever recorded at a location for that day of the year) were set, compared to 29,889 daily record lows. That is a ratio of more than 2 to 1.
Moving to the next level of extreme, in 2018 the number of record monthly highs (the highest temperature ever recorded at a location for any day of that month) was 3249, compared to 997 record monthly lows. That is a ratio of more than 3 to 1.
Finally, in 2018, 394 all-time record high temperatures (the highest temperature ever recorded at a location, regardless of the time of year) were set, compared to only 59 all-time record lows. That is a ratio of over 6.5 to 1.
This is exactly as has been predicted for some time: a small change in average temperature results in a disproportionately large change in extreme weather events. So the ratio between hot and cold events goes up as we move from daily, to monthly to all-time records. Note that this data comes from 8209 weather stations; the kind of coverage required to think broadly.
We have already begun to answer why close to 0.4 degrees Celsius of warming in one decade is significant. That is the increase in average temperature and does not represent the shift in extremes that comes with it.
To make this concrete, while we’ve had a cold enough winter (though not as cold as the average winter 60 years ago), Australia had another scorching summer of extremes:
“A total of 206 records were broken over 90 days in the country, including record-high summer temperature in 87 locations, record-low summer total rainfall in 96 locations, and record-high summer rainfall in 15 places…It was the warmest January on record for Australia in terms of mean, maximum and minimum temperatures. The national mean temperature was 2.91 deg C above average”(source: https://www.straitstimes.com/asia/australianz/more-than-200-weather-records-broken-during-australias-angriest-summer).
In keeping with the principle that this article started with, it is also not enough to consider what happened in Australia over one summer, and if I had not provided the record data from 2018, you would be right to object. Why what happened there is of interest to us is to illustrate that: what’s happening in our part of the world may be very different than what’s happening somewhere else at the same time; that the extreme weather events predicted to come with a seemingly small increase in average temperature are occurring, and; that when these extremes occur it causes significant problems. So, for example, we find that in one part of Australia farmer income was cut in half by drought this year (source: https://www.dailytelegraph.com.au/news/nsw/farms-predicted-to-cop-average-69k-loss-this-season/news-story/885c3a8428fa47b9084940845dd97159?nk=442b5ea095ea208b707999d748abcdb1-1557192342).
Raising the average temperature of the earth by approximately 1.2 degrees Celsius since pre-industrial (as we have done), is not like raising the temperature on your thermostat by 1.2 degrees. The earth’s climate has to equalize heat across land, water, air and ice, and it has to do so while the whole earth is spinning around its axis and revolving around the sun. It is a very dynamic and complex system.
So next time you’re not happy with the weather out the window and you’re wondering how it can be snowing in May if the climate is warming, remember to broaden your perspective.
The next article in this series will be on the principle “climate science is not uncertain.”
SOURCE – Leo Lepiano