Kevin Myatt is The Roanoke Times' weather columnist.

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Someone recently left this message on my voice mail: "Well, here's your global warming, what you and these other characters have been pushing for."

A strange message, because I've mentioned the phrase "global warming" in only six of more than 100 columns during the past year. Also, I've repeatedly stated that no short-term weather event can be conclusively linked to any long-term climate trend. Even the most ardent global warming researchers stress that no single event or single season of weather can be attributed to global warming with any certainty.

But the issue has been raised much more widely than by merely one anonymous caller. Is this mild winter the face of global warming in our times?

During this one final spurt of mild weather before major weather pattern changes could forever change the way winter 2006-07 is remembered, I will consider that question.

Global warming refers to the observed rise in worldwide average temperatures of about 1 degree Fahrenheit over the past century, which has been most evident since 1980, and the computer climate model projections that the warming will continue and likely intensify. For this column, we'll leave it at that, and not get into what may be causing it or what, if anything, should be done about it.

It's important to keep in mind that no concept of global warming includes the sudden, total abolition of winter.

Folks in Kansas and Colorado who have had house-burying and cattle-killing snowdrifts in recent weeks would howl at the notion that global warming is causing a less severe winter.

When it comes to weather, our perspectives are local and our memories are short. Those people in Monday's newspaper who were sunbathing on Coney Island pondering global warming are already forgetting that New York last year completed its first recorded run of four consecutive winters with 40 or more inches of snow. And the city is not yet a year removed from its largest 24-hour snowfall on record.

Every winter weather pattern consists of blobs of relatively mild and cold air circling the north pole. Sometimes, the blobs get stuck for a while, and one area basks while another shivers. While we've been wearing shorts and short sleeves, some parts of Alaska and eastern Asia have been in the throes of temperatures below minus 30.

Global warming suggests that, over many years, cold snaps may gradually become less frequent, less severe and shorter, while warm spells may gradually become more frequent, more intense and longer.

Gradual is the key word. Short-term weather makes big jumps up and down. Global warming is more insidious and is mostly seen in a gradual creep upward in average low temperatures rather than in dramatic spikes upward in high temperatures.

In other words, Arctic ice shelves aren't shrinking because of blazing hot temperatures -- they've been melting because it's been getting a little less cold each winter than it once did.

This winter would have been mild with or without global warming. Three major atmospheric oscillations -- the El Nino Southern Oscillation, the Eastern Pacific Oscillation and the North Atlantic Oscillation -- have shifted into phases that have strongly favored mild weather in our region. These oscillations have been going on for centuries, long before anyone invented a combustion engine or former vice presidents started doing climate documentaries.

However, it cannot be ruled out that global warming could be having some effect on day-to-day temperatures. It might be just the difference of a day reaching 68 instead of 66, or a night dropping to 45 instead of 42.

The connection between global warming and temperatures on a specific day or even through a season cannot easily be proved or disproved. But if an effect does exist, it would be in the form of a slight, latent warmth nudging temperatures up just a bit -- not an atmospheric flame thrower that can fuel a warm spell several degrees above normal for multiple weeks.

So an overall conclusion: This winter has not been made mild by global warming, but it is possible that it has been a bit milder that it would have been because of it.

When the new pattern kicks in next week, someone may want to call me and say: "Well, here's your Ice Age."