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Weather v climate

13 May 2020 | OP ED Watch

We often make sport of the ever-shifting and opportunistic definition of “climate” as opposed to “weather”, by which any unusually warm or stormy events are portents of climate whereas, say, a string of blizzards in May is just the meaningless vagaries of weather. Recently a kind adult patted us on the head and explained that we were ignorant of the scientific basis of the difference. To aid in our education they provided a link to a NASA page wherein there is enough hand-waving to power the next Apollo mission. It declares that: “The difference between weather and climate is a measure of time. Weather is what conditions of the atmosphere are over a short period of time, and climate is how the atmosphere ‘behaves’ over relatively long periods of time.” All of which says precisely nothing, which is why the definitions keep changing depending on the day’s weather. But soon it gets worse because their first example to illustrate climate change is something that hasn’t happened.

The page begins with the usual rhubarb: “When we talk about climate change, we talk about changes in long-term averages of daily weather. Today, children always hear stories from their parents and grandparents about how snow was always piled up to their waists as they trudged off to school. Children today in most areas of the country haven’t experienced those kinds of dreadful snow-packed winters, except for the Northeastern U.S. in January 2005. The change in recent winter snows indicate that the climate has changed since their parents were young.” These examples were predictable even though they are invented: As we have noted, there has not actually been a decrease in snow cover in the Northern Hemisphere since 1967. On the contrary, winters have gotten snowier, as have falls, while springs have become less so.

Ah. What of the heat waves? The page again predictably says “If summers seem hotter lately, then the recent climate may have changed.” But as the Spartans said to Philip of Macedon, “If”. NASA sort of hedges here, saying “In various parts of the world, some people have even noticed that springtime comes earlier now than it did 30 years ago. An earlier springtime is indicative of a possible change in the climate.” But in other parts, they haven’t. And summers don’t seem hotter. (See our 1919 or 2019 quiz and our Climate Emergency Tour for more on this point in Canada.) But if they did… nudge nudge.

NASA even acknowledges the jibe that climate is what you expect and weather is what you get. But it overheats both: “climate is what you expect, like a very hot summer, and weather is what you get, like a hot day with pop-up thunderstorms.” Or really cold weather in May in Ottawa including frost warnings.

The NASA page brushes such possibilities aside and goes all in: “The reason studying climate and a changing climate is important, is that will affect people around the world. Rising global temperatures are expected to raise sea levels, and change precipitation and other local climate conditions. Changing regional climate could alter forests, crop yields, and water supplies. It could also affect human health, animals, and many types of ecosystems. Deserts may expand into existing rangelands, and features of some of our National Parks and National Forests may be permanently altered. The National Academy of Sciences, a lead scientific body in the U.S., determined that the Earth’s surface temperature has risen by about 1 degree Fahrenheit in the past century, with accelerated warming during the past two decades. There is new and stronger evidence that most of the warming over the last 50 years is attributable to human activities.”

Scary stuff, huh, kids? Better pester your parents to support the Green New Deal. Except to its credit, after betting the stack NASA suddenly folds. “Yet, there is still some debate about the role of natural cycles and processes. Human activities have altered the chemical composition of the atmosphere through the buildup of greenhouse gases – primarily carbon dioxide, methane, and nitrous oxide. The heat-trapping property of these gases is undisputed although uncertainties exist about exactly how Earth’s climate responds to them. According to the U.S. Climate Change Science Program (http://www.climatescience.gov), factors such as aerosols, land use change and others may play important roles in climate change, but their influence is highly uncertain at the present time.”

So the science isn’t settled. There are uncertainties, there is still debate, their influence is highly uncertain. Why, one day we might even get the role of solar cycles here, or past temperature records, and really have the makings of an intelligent primer.

One comment on “Weather v climate”

  1. Wednesday mornings are spruced up by the levity and wry humour of the CDN.
    To balance the fun with some solid dance floor, having links to the data of, say, snowier winters, will assist greatly in assimilation of the greater scene here on earth, “climate” wise.
    It’s too too easy to get caught up in the swirling tides of incredulity and baseless speculation. Like ascending a tall tree, you need harnesses and belay lines, anchors and crampons. Gravity is relentless.

    Your input to this global discussion is appreciated. Thank you.

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