The Latest Storm of Hyperbole

Published April 1, 2000

A mere 20 years ago, climatologists were the offensive guards of the weather world–the dutiful servants whom nobody noticed unless they got flagged for holding, moving before the snap, or popping the line judge with a right hook.

The atmospheric sciences world didn’t really care what climatologists did, since they were largely deemed irrelevant to the important issues of weather forecasting, air pollution meteorology, and codifying the behavior of tropical cyclones. Rarer still was the media coverage of any topic climatic.

Ah, those were the days. . . .

Now, climatologists are not only the quarterbacks, but the owners, general managers, and the Commissioner! Rarely a day goes by without two or three breaking news items, splattered across the airwaves, about the latest and greatest new discoveries in climate science. (With so many remarkable breakthroughs, you’d think we’d have this whole climate business figured out by now.)

These newsy climate items are typically reported using a tried-and-true formula such as the latest two-column spread in Newsweek (January 31) about the Pacific Decadal Oscillation (PDO), entitled: “What’s Up with the Weather? It’s Hot, it’s cold, it’s wet, it’s dry. Scientists say: get used to it.”

We climatologists who’ve been suffering through this breathless media climate panic for the past decade or more can recite that type of article’s content without even reading it. The names of the climate “phenomena” may change–the PDO, global warming, El Niño, La Niña, the Southern Oscillation, the Arctic Oscillation, yadda yadda yadda–but the story is exactly the same. For fun, let’s make it fill-in-the-blank:

Scientist Announces Scary Climate News [insert date here]

Professor [Jason/Helga] Smith of Northeast [Massachusetts/Missouri/Illinois] University at Springfield discovered that [ENSO/ozone hole/the Norwegian Oscillation] is closely linked to global [temperature/snowfall/circulation], and that means trouble! “Our period of pleasant weather is rapidly coming to an end,” Smith said. “Our new analysis, which I just finished before my morning [coffee/espresso/cappuccino] break, shows that the [X/Y/Z] effect is taking a turn for the worse, which means we can expect more [droughts/floods/hurricanes/tornadoes/blizzards] in the [Pacific Northwest/Southeast/New England] and Washington, D.C., than they’ve experienced in decades.”

Exacerbating this problem is the rapid development there since the last time [X/Y/Z] was at similar levels decades ago. And some scientists, including Dr. [Trenberth/Wigley/ Santer/McCracken] are convinced [X/Y/Z] is linked to global warming. Presidential candidate [Bill Bradley/Al Gore/John McCain], who’s campaigning in [California/California/California], has already proposed a $500 million federal program to combat this problem. According to [Bradley/Gore/McCain], “If the Senate doesn’t pass the Kyoto Protocol soon, our children can expect more [droughts/floods/hurricanes/tornadoes/blizzards] than we’ve ever experienced in our planet’s history.”

Today, it’s the PDO

The latest version of this hubbub is about something called the Pacific Decadal Oscillation, or PDO. The idea is that Pacific basin surface water temperatures oscillate between warm and cold phases off the coast of the Americas about every 20 to 40 years. We’ve been in a warm phase since the late 1970s, but some scientists think we’ve already entered the beginning of what will be a prolonged cold phase.

The phrase PDO was coined about four years ago but has only now come into vogue. The PDO is related to something called the North Pacific Oscillation, a long-term pattern of alternating pressure scientists have known about for decades. Some scientists, including Oregon State Climatologist George Taylor, think the PDO is linked to global temperatures. “The PDO explains a great deal of the variation in global air temperatures in the last century,” Taylor says. “Few can explain why temperatures . . . dropped [after 1945], even though CO2 was increasing rapidly.”

But El Niño/La Niña enthusiasts needn’t worry. That cause celebre of every global weather blip from Antarctica to Ellesmere Island will still occur, but perhaps with a differing frequency. The newly formed cool conditions in the eastern Pacific may generate more La Niñas, but where we are in the El Niño/La Niña cycle relative to the PDO cycle is always a matter of speculation. According to University of Washington circulation guru John Wallace, “It’s very hard to know where you are [in the PDO cycle] at the time.”

For example, during the Pacific cold period that lasted from post World War II to pre-Jimmy Carter, “We had this long-lived El Niño in 1958–1959. Now we ignore that episode when looking at the larger record. But at the time, it might have seemed as if we were entering a warm period,” Wallace explained.

In truth, climatologists have been looking for cycles in vain since they were playing the role of offensive lineman. And with few exceptions (such as Bill Gray’s Atlantic hurricane forecasts), despite decades of effort, climate elements are not predictable over large regions of the globe even one month in advance, let alone several years or decades ahead. Of course, it’s quite easy to determine that you’ve been in a cycle a few years after it’s ended.

Perhaps the PDO really is the missing climate link–the key to predicting our climatic future. If so, does this mean we’re now entering the beginning of the end of the era of global warming hysteria and histrionics?

Here, we are willing to offer a prediction in which we have very high confidence: No! The global warming frenzy will not end. There are two very good reasons why.

First, too many federal (and private) employees are paid good bucks to push a forthcoming global warming disaster. The weather is always going to be bad somewhere, and it’s easy to find people making the case that they know what caused it.

Second, we can safely predict that global surface temperatures will continue to rise, and this will keep the global warming presses rolling. The simple facts of population growth and land-use changes will continue to warm the air around weather station thermometers, making every year’s ersatz temperature appear to be well above the long-term mean, even in the theoretically de-urbanized records. This will create an ever-growing disparity between the surface and satellite-measured temperatures (which incorporate data over the entire thickness of the atmosphere), regardless of our status relative to the PDO cycle.

So, until tomorrow or the next day, when the next new climate cycle or global teleconnection is discovered, we can revel in the PDO, and in Newsweek‘s closing spin on the climate change issue, “Chances are we’re going to have to come up with a whole new definition of normal.”

Well, folks, we’re afraid this is it.


Mantua, N.J., et al., 1997. A Pacific interdecadal climate oscillation with impacts on salmon production. Bulletin of the American Meteorological Society, 78, 1069-1079.