Global warming can never hope to be understood properly by assessing the temperature or trends in temperature or precipitation in a single locality or region. That is because the effects of warming do not affect all regions equally. In fact, it should be understood by the true scientist that warming will NOT affect all areas in the same way.
Let's look at that last example posted by kland first: heavy ice near the North Pole. Why would global warming predict that?
Consider the following:
1) The warmer the planet, the warmer the oceans, and the more evaporation they experience.
2) The warmest regions of the earth being those nearest the equator, the greatest evaporations take place there, which also factors into the potential for tropical storm generation in that same region.
3) The moisture-laden clouds that form in the tropical regions are blown great distances, forming the bulk of precipitation received in northern latitudes.
4) Rainwater is, of course, fresh water.
5) With much higher levels of evaporation in the equatorial regions, particularly the areas just north and south of the equator, and greater precipitations in northern latitudes, electrolytes and salts will concentrate more quickly in the tropics, effectually increasing the discrepancy in sea salinity between the poles and the tropics.
6) The reductions in salinity in the polar regions cause greater amounts of ice to develop, even without a reduction in overall temperatures, because higher salinity reduces the temperature required to form ice.
To understand how much effect salinity has upon the ocean in terms of other aspects, namely ocean currents generated by the salinity differences, the following article is a good primer on the subject.
http://ocean.stanford.edu/courses/bomc/chem/lecture_03.pdfNow, let's consider the earlier examples of increased snow precipitation.
Snow, like rain or other forms of precipitation, comes from water which must first have evaporated. Higher temperatures increase the evaporation of water, making heavier snowfalls possible. Furthermore, higher temperatures increase the capacity of the atmosphere to absorb evaporation from the ocean, i.e. the saturation point, and thus make possible the heavier precipitations from weather systems, including both rain and snow. The fact that "snow is cold" does little to mitigate the more significant fact that snow would not exist if it did not first evaporate, and evaporation happens best in a warm environment.
Consider this: heavier snows come at temperatures nearer the freezing point. When the weather is extremely cold, snow is rare. Thus, even an unusually heavy snow is itself, temperature-wise, an indication of warming.
Blessings,
Green Cochoa.
