Current Wisdom

NO FACT CHECKS PLEASE

One of the readily available newspapers we often pick up is the Richmond Times-Dispatch. We like the RTD for its no-nonsense reporting on matters climatic (and maybe because they quote us all the time).

So we were rather surprised to see on June 16, in the “World Focus” section an AP story which said this:

1. The Chinese government believed a seismologist (that’s a guy who studies earthquakes) who said there would be big floods last year, “perhaps the worst in 100 years.”

2. He predicted the floods by the relationship (???) between clouds and earthquakes. According to the story, “over years of looking at a special type of cloud, Huang [the seismologist] found that the areas where clouds were concentrated received a drought the following year.”

3. Global warming was involved in the floods, which are getting worse. According to AP, “As hurricanes, floods, and other disasters become more common—perhaps because of global warming...”

4. There will be more floods in China this summer: “This year, one expert has warned that southwest China will have floods in July and August.”

Here are a few bits of contrapuntal reality.

1. Earthquakes do not cause floods unless they bust a dam. The Yangtze river, site of the 1998 floods, had similar or greater floods 10 times in the last 50 years.

2. Where it is cloudy one year says nothing about the next year. Otherwise, forecasting next year’s weather would be a snap. If Huang were correct, he would have cornered the Pork Belly market long ago, and wouldn’t be gaming the Chinese government for a living.

3. A zillion articles in the refereed scientific literature show no increase in hurricane strength or frequency. The United Nations Intergovernmental Panel on Climate Change (a self-appointed “consensus of scientists”) also finds no evidence for an increase in extreme weather.

4. If it is summer in China and there are no floods, we are on a different planet.

HEARD HERE FIRST

Our Wisdom boilerplate about “spinning against some popular grain” sure applied to our take on El Niño published in the Advisory that hit your mailbox in early Spring, 1998, or some 18 months ago. We boldly said:

• “It’s not at all clear that this Niño has imposed a net cost, either in terms of dollars or lives, on the United States,”

• That El Niño’s suppression of strong Atlantic hurricanes would result in less damage and mortality than average, saving several billion dollars, and

• That the warm winter saved about 5 billion dollars in heating expenses, and many more lives than were cost by increased storminess associated with El Niño.

In a newspaper op-ed that printed nationally in April, 1998, we opined that El Niño probably saved the nation about $15 billion.

The most recent issue of the Bulletin of the American Meteorological Society contains an article by renowned climatologist Stan Changnon. According to Stan, because of El Niño:

• “Benefits included an estimated saving of 850 lives because of the lack of bad winter weather,” and

• “The estimated direct losses were about $4 billion and the benefits were approximately $19 billion.”

After October, 1997, Changnon wrote, “The press blamed all weather events on El Niño, and the concept that generally benign weather conditions would exist in the northern United States and be beneficial disappeared from the media stories.” Changnones comment was based upon an extensive content analysis of 2000 news stories in an upcoming book, El Niño 1997-98, from Oxford University Press.

We’re in especial agreement with Changnones conclusion:

STORMS IN DECLINE?

We’re not the only ones who have noticed that many radio news programs in August began with a story about this or that terrible storm or this or that terrible drought or terrible wildfire. Tropical Storm Dennis probably garnered more air time per mile per hour of wind than any storm in history.

Writing in a recent issue of Geophysical Research Letters, Boston University’s Jeffrey Key and Alan Chan describe statistically significant decline in the number of midlatitude low pressure systems in both winter and spring. It’s interesting to contrast this with studies from the National Climatic Data Center (NCDC) that show an increase in national rainfall of about 10%. Few doubt that NCDC’s finding is real. So either we’re getting more rain out of fewer lows, or the frequency and/or intensity of non-low-pressure- related rain, such as summer thunderstorms, may be increasing.

Midlatitude low pressure systems, Advisory readers do not have to be told, derive their energy from the jet stream, which itself is governed by the temperature contrast between tropical and polar latitudes. Greenhouse warming should be much larger in the high latitudes than in the tropics, reducing this contrast and therefore reducing the jet stream’s energy. Which, of course, should weaken the strength of midlatitude low pressure systems.

Spring cylcone frequencies in the mid latitudes of the Northern Hemisphere have been declining over the last four decades.

COVERING UP

One of the side issues that has been simmering while the greenhouse effect boils over has to do with another potential cause of climate alteration: changes in land use. When blacktop or housing developments replace forests, the local temperature regime changes considerably. A more subtle (but real) effect occurs when farms replace forest.

Canadian researchers Walter Skinner and Jacek Majorowicz, writing in the journal Climate Research, explored the relationship between climate change and land use in northwestern North America. Both that region and Siberia have experienced the largest winter warmings this century. They examined the relationship between surface air temperatures in long term historical records and ground surface readings taken from wells.

The more traditional temperature records show much less warming than the ground surface records, because the ground-based records tend to be in settings that have been disturbed, usually where forest or grassland has been turned into farms. The authors argue that the additional warming which results from this changeover is, perhaps erroneously, generally attributed to the greenhouse effect.

Another researcher, T. J. Lewis, writing in Geophysical Research Letters, calculated the amount of local warming that results from deforestation of boreal (Siberian and Canadian) lands. They found that it resulted in 0.5°C to 2.0°C of warming.

It turns out that this range of temperature change they attributed to deforestation isn’t much different than what one might expect from greenhouse effect changes. It’s interesting to note that the area that has experienced the most warming, Siberia, has also experienced the largest deforestation.