It's probably that we take the short view.

"There are times when I don't want to be proven right, and this is one of them," said Tony Lupo, University of Missouri-Columbia atmospheric scientist, who last winter forecast warmer, dryer weather through spring and most of summer. "I think we can expect dryer-than-normal weather for the balance of summer. May was exceptionally dry in central and eastern Missouri, and the trend is for summer to be drier and warmer than normal when May is dry."

A dry spring and early summer doesn't necessarily mean drought for the balance of the growing season, but weather patterns feed on one another, and tend to perpetuate themselves, added Lupo, giving credence to the old country adage that "all signs fail in dry weather."

By contrast take 2004, with the fifth mildest summer on record in much of the Midwest. Ample, timely rains over most of the mid-continent helped produce all-time record corn and soybean crops.

"Last year, we experienced typical pre-El Nino conditions that brought regular rainfall and mild temperatures," said Lupo. "El Nino pretty well ran its course during winter and into spring and has now declined into a neutral condition."

Lupo is referring to the phenomenon when vast tracts of the eastern Pacific Ocean heat up or cool down. This oscillation has been going on forever, but its effect on North American weather has only been well understood for the past 25 years or so.

El Nino describes the warming of Pacific waters along the equator. As the ocean warms, a terrific amount of energy-and moisture-is released and can have a profound effect on North American weather. In El Nino years, precipitation occurs about every week or 10 days; frequent, lighter rains are better for crops than now-and-then gully-washers.

El Nino's cantankerous little sister, La Nina, refers to just the opposite. The equatorial Pacific cools down and induces hotter weather and longer rainless periods over the North American mid-continent.

"And we have other influences on our weather and on our climate," said Lupo. "Climate is not static-it's always changing, so that we have cycles within cycles. Variations in solar output, for example, can affect climate dramatically."

Until the 1990s, the popular view of climate change was that climates change gradually, over a period of centuries.

"However, evidence pieced together over the last few decades shows that climate has changed much more rapidly-sometimes abruptly-in the past and therefore could do so again in the future," reads a report from the National Research Council.

In the context of past abrupt climate changes, rapidly typically means on the order of a decade or two, rather than hundreds of years, the report continued. Examples of abrupt changes in the 20th Century include the rapid warming of the North Atlantic from 1920 to 1930 and the Dust Bowl droughts of the 1930s.

There's pretty good evidence that we may be in one of those abrupt climactic changes now. During the last decade of the 20th century, the earth's surface temperature records were set and broken more than once, giving good evidence that we are in a period of what's popularly called "Global Warming"-at least for the time being.

While most scientists now agree that the globe's average temperature has climbed by a degree or two during the past few years, there isn't much consensus on the long-term implications. And there's even less agreement on whether, or how much, human activity is contributing to the earth running a temperature.

On one side of the argument are those adherents who often seem to be more concerned about the earth than about earthlings. These include environmentalists who believe such activities as internal-combustion engines, electrical power generation and industrial plant smokestacks and the carbon dioxide they spew into the atmosphere are causing radical climate jumps that will trigger meteorological chaos.

"I have studied climate change, or Global Warming," said Lupo. "I don't see a warming climate as being necessarily man-induced. My hunch is that these changes have occurred before and are well within what Nature is capable of doing on her own.

"If the earth is warming up slightly, I don't know that is at all a bad thing," he added. "More important is how precipitation patterns may be affected."

Lupo points out that the earth has had prior relatively balmy periods, long before man was burning much fossil fuel. For example, between about 900 A.D. and 1200 A.D., the globe's average temperature increased by about three degrees, during what is called the Medieval Climate Optimum. Vikings colonized Greenland around 950 A.D. and it was so warm there that those Scandinavian settlers grew crops and pastured livestock on what had been frozen tundra.

And would be frozen tundra again. Not too many years (in climactic terms) after the Medieval warm-up, the earth cooled down sharply and entered what has become known as the "Little Ice Age." The Vikings had to pack up and leave Greenland.

Those of us with 35-year-old memories may take the doomsday predictions of Global Warming with a large grain of salt. Back in the late 60s and early 70s, we had three or four winters in a row with below-normal temperatures, followed by exceptionally mild summers. At least half of the conventional wisdom then had us going into another Ice Age.

And, if your view of weather and climate is shaped by media meteorologists, remember that those guys thrive on superlatives and their jobs depend on their generating a certain amount of alarm. In 1993, we had a 500-year flood in the Midwest and the "Storm of the Century" that paralyzed the East Coast that winter. In 1995, there was the "Great Chicago Heat Wave." A year later, we had another "Great East Coast Blizzard."

Tony Lupo said that it would be a mistake to read too much into any long-range forecast-including his own regarding the rest of the 2005 growing season.

"We cannot really rely on it," he observed. "Long-range weather forecasting is still a dicey proposition, and I have rolled snake-eyes before."