Atmosphere And Weather

How Weather and Climate Differ



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Global warming, global cooling, the whole debate further makes it difficult than it already is for people to understand the differences between weather and climate. In fact, it fuels the debate. Yet the differences are easy to understand.

A big part of the confusion is how each are used in ways that almost seem interchangeable. For instance, in the debate previously mentioned, some will cite 'proof' of global warming as being the melting of the North Polar ice cap. There is a problem with this (beside the fact that this has been continuing since the end of the last ice age, and not just recently). The word 'warming' refers to heat. Heat is actually a function of weather, not climate. Using the term with the word climate' gives it an unintended and often ignored meaning. We will get to that.

Weather is what happens in the atmosphere in a very specific location at a specific time. This can vary widely over the weather of a location even relatively close by. For instance, at your house, you might have temperatures of 20 with a 5 mph wind, but at the weather station, a couple miles away, the temperatures could be 18 with a 10 mph wind.

Weather can also be produced by the work of man or other factors. For example, near a forest fire, there may be powerful updrafts and wind devils that are produced directly because of the fire.

Your local weather is a combination of barometric pressure, air speed, air direction, precipitation or lack of precipitation and amount of precipitation if there is any, and temperature. Each of these can have a bearing on each of the others, for a given time period.

Climate, on the other hand, is the average of all the weather aspects over a longer period of time, usually at least a year and sometimes much longer than this. This means that just because the weather of one day in the month was -20 degrees, not much can be said regarding the climate, even as compared to an average of the month.

Explained in another way, if the average temperature for the month of January, averaged over the past ten years, is 30 degrees (this would be climate), having a single day at 20 (weather) really means nothing. There are still 29 days in the month that would have to be averaged in order to be able to even compare it to climate. If half of those days were 50 degrees or more, the whole month would be considered unseasonably warm, despite the one extremely cold day that might even break low temperature records.

This is where the unusual meaning comes from when combining "global" and "warming". Since warming is a function of weather, if there was a global warming of 1 degree, by forcing it into terms of climate, it would mean that every point on the earth would have to be 1 degree warmer, for every day, over a protracted period of time, for instance a year. Nothing of this sort has ever been recorded in history.

So for clarity, we can say that there is very bad weather over Antarctica in the middle of the summer. The wind is blowing 100 mph, and the temperature is -40. This would be weather. But the climate of Antarctica is an average of 150 mph winds and a summer temperature of about -10 to 20 degrees. The two cannot be compared unless the weather continues for a long enough period of time to make an honestly direct comparison. If it did, we would then say that the winds weren't as strong as normal, but the temperature range was slightly above normal. (Note: that is temperature range, rather than temperatures, heating, or cooling.)

It seems that much of the confusion over global warming and cooling is driven by the confusion over the difference between weather and climate. Understanding clearly what the differences are is the first step toward arriving at the actual truth.

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