Of course we had rain before the temperature average increased. And we had snow, and landslides, and wildfires, and lightning. That is not what we are talking about.
We are talking about changes in the previous patterns, and long term trends in all sorts of things. Just like some places are seeing increases in rainfall, others are seeing decreases in rainfall -- long term changes; we are also seeing larger tropical zones (2+ degrees latitude north and south for 8.5 million square miles more tropics) and we are seeing some areas getting colder.
Overall, the average temperatures are warmer, but that does not mean that they are warmer everywhere.
Warmer temperatures mean that water has lower density -- and greater volume. Higher levels of carbon dioxide mean less heat is lost back out into space, and higher acidity on average in the oceans. But even this is is not all over -- it depends on the temperature; colder water absorbs more carbon, which means that the richest fishing areas will be most affected. It depends on the adjacent land -- limestone areas counteract the acidification somewhat, while granite areas will be affected more.
So sure, it cools things to condense water, but there is more heat to evaporate the water. And the clouds that do not produce precipitation -- cause more warming. Because water vapor is GHG, but it depends on carbon dioxide to "get started".
Warming climate melts more ice -- most all glaciers are melting, as are the Arctic and Antarctic and Greenland ice. It is the land ice that will have the greatest affect on ocean level. But the lowered albedo of open water means there is more heat absorbed.
Warming climate melts the tundra, which is releasing lots and lots of trapped methane. Methane is a far more insulating GHG than is carbon dioxide; so we will see more and more warming now that we have passed the probably threshold of 350ppm of carbon dioxide.
Warming climate is causing plants and animals to die off. Plants in particular are on the other side of the carbon dioxide / oxygen balance in the atmosphere. The large boreal forests that have already died are releasing the carbon dioxide they had absorbed at a much higher rate than if they had a "normal" life cycle.
[Edit: I am not panicking; but I am very concerned. I do believe the scientists, though; because they have looked at all the factors, and as time has gone on (in the decades that they have been working on this), the trends are worse than originally thought; and none of the data indicates that this is anything other than anthropomorphic climate change.
Things have already changed, and we need to acknowledge the facts. We need to do whatever is possible to minimize future changes.]
Last edited by NeilBlanchard; 12-23-2010 at 10:03 AM..
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