Weather and climate are not the same

Magnificent clouds and sun over the Willamette Valley

I'm constantly frustrated at the popular media's flawed insistence on interchangeably using the terms "weather" and "climate". They are NOT the same thing. Are they related? Yes. But they are not the same. The (intended?) result of this synonymizing is a relative dumbing down of the public's understanding of the two...and the subsequent dismissal of the realities of a changing climate. I can't tell you how many times I've heard people say something to the effect of "We set record low temperatures here for the month of (pick one)! You can't tell me the earth is heating up!"

Well...yes we can.

You see, it's really not the average global temperature that's the most interesting (but it's what many media outlets report and what many scoff at - "Psh! Who cares if the average temperature increases by 2-3 degrees?!"). Really, it's all about the extremes - the lows and the highs, not averages. So it's the variation around the average that really matters.

Think about it this way. Consider an average of 50 degrees F (close to the average annual temperature in Eugene, OR) derived from an average yearly low temperature of 40F and an average yearly high of 60F. If you're more of a mathematical learner, it'd look something like this:

(temp1+temp2) / number of temps = average temp

OR, from our example above,

[(40+60)/2]=50

But monkeying with the low and high can still produce the same result. For example,

[(10+90)/2]=50

A world in which this low-high scenario plays would be a very different one to live in than the one provided in the first example, no? And while I've exaggerated the low-high in the second example for demonstrative purposes, this low-high concept turns out to be incredibly important to the critters living in an area (i.e., the physiological thermal tolerance range of a species), especially for critters that are already living in environments at or near their ability to survive.

Now let's assume the average goes up a few degrees, as average annual global temperatures are predicted to do (see the most comprehensive report to date). Since it's really the low and high temperatures (the variation) that drive the average, doesn't it make sense for us to be more concerned about these two ends of the spectrum - the extremes? And as it turns out, those two ends are getting further and further apart with only a slight change (an increase) to the average. In other words, the variation around the average is increasing...and we're seeing more and more "extreme weather" events the world over. Welcome to the new norm.

But back to the topic at hand...

Weather takes place on relatively short timescales (e.g., days to months) whereas climate takes place on longer timescales (e.g., seasons and years to millenia). A newsy Q and A blurb from NASA's Global Climate Change program did a good job of explaining it in text. But for many, it's often more helpful to visualize an idea. This short animated video does a good job explaining the difference between the two.



Another analogy would be to think about weather as what clothes you might pack for a weeklong Spring vacation trip to Florida. I'd probably pack a couple of pairs of shorts and a couple of pairs of warmer clothes in case it turned off cooler (weather). But if I were planning to move to Florida, I'd likely get rid of most of my cold weather gear in favor of the shorts and shirt sleeves - so it's the proportion of cool and warm clothes (climate) that would matter to me more.

Perhaps if the popular media could get this little synonymizing nuisance cleared up, we might be able to better understand and accept these extreme weather events (anomalies that are becoming more commonplace) as part of our changing climate.

We all know smokers who live into their eighties, and health nuts that drop dead in their forties. Most people understand and accept anomalies in fields like health care and economics, and we need to do the same with climate issues. ~ Eric Fetzer

Planning for Extreme Weather Events

As I was sitting in the office one fine June day in 2009 watching a severe weather cell steamroll its way through the Willamette Valley, I couldn’t help but marvel at its awesome, enveloping presence and destructive potential. My officemates and I were first alerted to its impending arrival by the rapid darkening of the skies to the East and South of us. Then, almost imperceptibly at first but rapidly building to a crescendo, the riparian songbirds began filling the skies in what can only be described as a frenzy. The office was abuzz with nervous excitement as we all watched the wind begin whipping the waterfront vegetation – gently at first but rapidly increasing to “violent storm” and “hurricane” force winds (literally; 3-4 categories stronger than “gale force” winds on the Beaufort Wind Scale). According to the NOAA Severe Storm Alert for the area, winds had already been measured in excess of 70 mph and a tornado watch was issued for some of the surrounding areas (rumor had it that one had touched down about 5 miles east of us; it was later confirmed by the National Weather Service). And the excitement level in the office was fed by alarming statements in NOAA’s Tornado and Severe Thunderstorm warnings for the area:

DOPPLER RADAR SHOWS CIRCULATING WIND PATTERNS THAT…MAY PRODUCE TORNADOES.

and

PREPARE IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD TO GROUND LIGHTNING.

But what I was most struck by (no, not lightning), was how these sorts of extreme weather events are becoming more commonplace in the Willamette Valley (throughout all of Oregon, the Pacific Northwest, and beyond, really). Indeed, tornadoes touched down in Oregon about 8.5 times per decade from 1950 through 1989, but touched down at three times that rate (~32 per decade) since (see below; data from NOAA’s National Climate Data Center). The trends look similar for Oregon’s extreme wind and precipitation events.

Number of tornadoes, by decade, that touched down in Oregon.

But extreme (think “outlier”) weather events are certainly not unique to Oregon. Globally, extreme weather events are cropping up with alarming regularity. One has only to watch the news for a couple of days to see a new high temperature “record setting day” in this place or that. Moscow, Russia, typically known for its cool (alright, cold) climate, had its first 100 degree Fahrenheit day last July. In fact, it had several 100 degree days this summer while dozens of other countries were also setting record high temperatures (see below). Los Angeles, California just set an all-time record high temperature (113 degrees F) while Seattle, Washington came one degree shy of setting an all-time record high September dewpoint (see an animation of the “moisture river” from October 2010, here).

Countries that set record high temperatures in 2010.

Climatologists indicate “extreme” weather events (think, 100-year flood event or the like) may become more commonplace as our planet experiences climatic changes. And extreme events can play a dramatic role in influencing a suite of biological and economic processes. One has only to search the web to find scores of examples (see some here, here, and here). Unfortunately, many of our biological and economic models do a relatively poor job of incorporating “infrequent” (and/or catastrophic) events. Partly as a result (see "The Black Swan"), natural resource management plans largely overlook these events when estimating future abundance and distribution of species. And disaster management plans are often ill-equipped to deal with large, catastrophic events that occur relatively frequently (project ARkStorm is a notable exception).

What is becoming increasingly clear is that as climate variability increases, the interval of “infrequent,” extreme events is decreasing. Is this novel in recorded human history? Not necessarily (think 1930’s US “Dust Bowl” droughts). We just happen to have recently been through a relatively stable period. But the importance of preparing for more frequent “extreme events” – both from a biological and economic perspective – should follow suit…but with enough urgency to put us ahead on the planning curve. Shouldn’t we at least have a sense for how the natural world might adapt to increases in frequency of these “extreme” events? Granted, extreme events are by their very nature, unpredictable. But we have smoke detectors and fire extinguishers in our houses in calculated anticipation of (and preparedness for) “the event,” even though the probability of it actually occurring is quite low. Shouldn’t we also be planning for these climatic, biological and economic low-probability, extreme events? Are we – as natural resource and economic managers – going to be prepared? Or are we going to maintain the status quo (e.g., crisis management) and be forced to shift our conservation efforts to “managed retreat”?