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Posted at 11:30 AM ET, 05/24/2010

Hurricane chimp's cheap shot at climate science

* Drier weather develops: CWG's Full Forecast *

Are poor hurricane season forecasts a reason to doubt climate science? A conservative Washington think tank believes the answer is yes, and they are using a monkey -- pardon me, "Dr. James Hansimian" -- to prove it. (The monkey's name, by the way, is a dig at well known NASA climate scientist James Hansen, who incidentally does not forecast hurricanes).

According to the National Center for Public Policy Research (NCPPR), a monkey rolling a pair of dice can more accurately predict the number of hurricanes that will form in a given season than any of the more sophisticated human methods. Moreover, the think tank implied in a press release on May 18, all climate science projections are about as reliable as hurricane season forecasts.

Now I have nothing against monkeys, nor do I nor most climate scientists claim that climate change projections are 100 percent accurate, but NCPPR's comparison between seasonal forecasts of hurricane activity and long-term climate predictions makes no sense -- it's like comparing apples and giraffes -- and falls flat as an effort to attack the credibility of climate science.

The press release makes clear where the "monkeying around" is directed: "The video isn't intended to needle the National Oceanic and Atmospheric Administration (NOAA) for its erroneous forecasts, but to make a larger point about our current understanding of climate."

"NOAA's forecasts have been wrong not because of a lack of dedication or competence of its forecast team, but because climate science is really still in its infancy," NCPPR president Amy Ridenour said. "We should remember this as we consider whether to adopt economically-ruinous caps on energy. If we can't rely on 6-month forecasts, how can we rely on forecasts of what rising carbon concentrations will do to our climate 25, 50 or even 100 years out?"

The think tank's key mistake lies in conflating short-term prediction of small-scale weather events, such as hurricanes and tropical storms, with long-term forecasts of large-scale, global climate (e.g., average seasonal or annual temperature and precipitation for a region or the globe). The geographical scales and timeframes of the two are far different, as are the tools needed to project them with any accuracy.

NCPPR also fails to state exactly what part of climate science is in its "infancy." For example, it's been known since the 19th century that certain gases, such as carbon dioxide, warm Earth's climate and that pumping more of such gases into the air will cause temperatures to increase. That hardly qualifies as a newborn science.

A seasonal hurricane forecast is simply not analogous to a seasonal climate forecast for, say, the summer in Washington, or a multi-decadal climate forecast as cited in NCPPR's press release. Conflating the two is flawed in much the same way it is to argue that because weather forecasters can't predict the weather two days from now with perfect accuracy, that we can't make informed decisions based on climate projections for the more distant future. They are two different things.

Here's how: With hurricane season forecasts, meteorologists examine particular factors that are known to encourage or inhibit tropical storm and hurricane formation. Such factors include the presence or lack of El Nino (warmer-than-average sea-surface temperatures in the equatorial Pacific Ocean), sea-surface temperatures in the area of the Atlantic where most hurricanes form, and other variables. The end forecast is determined in part by looking back to the nature of hurricane activity in previous years when conditions were similar.

This year, forecasters are concerned that the disappearance of El Nino, combined with unusually warm sea-surface temperatures in the Atlantic, will lead to a rude awakening after last year's quiet season.

Although hurricanes are nature's largest and fiercest storms, they are weather phenomena that are significantly influenced by small-scale factors, ranging from ocean eddies to wind shear to the amount of dust in the atmosphere. Predicting how these influences will line up whenever a particular storm tries to develop is no easy task, for man or monkey.

To project climate change, on the other hand, scientists examine the larger factors that influence climate on long time scales. Such natural and manmade factors include variations in solar output, changes in the composition of Earth's atmosphere (including concentrations of greenhouse gases), and variations in Earth's rotational axis around the sun, among others. These natural and manmade factors are fed into long-term climate models, which are first calibrated by making sure they accurately simulate past climate.

While some sources of climate variability are not so predictable, such as volcanic eruptions that can cool the climate for several years, many of the factors are actually measured quite well, and there is a high degree of confidence in how they will change in the future. For example, in 2007 the U.N. Intergovernmental Panel on Climate Change concluded that there is a 90 percent chance or greater that recent warming is mainly due to human activities, and a high likelihood that more significant climate change is on tap for coming decades.

Determining the number of hurricanes that will form in a season is actually more complex than projecting that the global climate will be warmer in 20 years than it is now, based on the likelihood that climate-warming gases will continue to increase due to industrial activities.

Interestingly, NCPPR is not far off in its contention that hurricane season outlooks have little accuracy, at least when issued far in advance of the season's June 1 start. Last year, for example, NOAA's initial hurricane season forecast called for between nine and 14 named storms to form in the Atlantic Basin, with four to seven hurricanes and two major hurricanes (Category 3 or greater). In reality the season underperformed, due in large part to rapidly strengthening El Nino conditions in the Pacific.

However, the think tank's effort -- presumably politically motivated -- to spread the message that climate scientists know as much about Earth's future climate as a monkey rolling a pair of dice is laughable. Not just because monkeys are funny, but because predicting that the climate will warm in the next several decades, due largely to increased concentrations of greenhouse gases such as carbon dioxide, is fundamentally different than forecasting a particular hurricane season, regardless of whether a human or monkey issues the outlook.

The views expressed here are the author's alone and do not represent any position of the Washington Post, its news staff or the Capital Weather Gang.

By  |  11:30 AM ET, 05/24/2010

Categories:  Climate Change, Climate Change, Climate Change

 
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