Glenn Rivers
EF1
Global Warming and weather extremes
I will state here that I find it a little irksome that some members of this forum complain over and over about the global warming alarmists...one gets the impression that these people are so bothered by believers in Anthropogenic global warming that they feel depressed and feel like these people are literally sucking the life out of them and crushing moral !
What I Believe: I happen to believe that global warming is not just a fad and that the odds are that the planet will continue to warm over the next century or more and that even though there will be some desirable consequences, they will be outweighed by the negative ones.
Now for what I do not believe: I do not believe that individual extreme weather events can be blamed on global warming. In fact, the claims after every extreme event that it must have been caused be global warming are something that bugs me as well.
I also do not believe in blanket statements that there will be much more extreme weather of all kinds. Rather, a more reasonable statement might be that just like the prevailing climate, extreme weather will change as a result of global warming, with some types of extreme weather becoming less common while others become more common. Some examples of extremes may not show any obvious trend, but may change in seasonality or geographic occurrence.
To use just one example: Hurricanes are a believable candidate for an increase under global warming, as it is very likely that SST's will be warmer, but even here there are many ifs and buts. Warm Water is not enough to guaranty stronger hurricanes if problems like dry air ingestion and wind shear also change under Global Warming.
The Tropical North Atlantic seems to be a particularly complicated environment for hurricanes, with some negative factors such as hot dry Saharan air suppressing convection and adverse wind shear sometimes preventing hurricane development even over deep areas of very warm water that could serve as high octane fuel. Recent research suggests that during the latter part of the "little ice age" atlantic hurricanes were very active. Perhaps moister conditions in the Sahel of Africa and or favorable low 900-300 mb wind shear conditions were common, and made up for slightly cooler water. This finding suggests that we can not assume that warmer SST's in the tropical Atlantic will lead to more or stronger hurricanes.
One model simulation of late 21'st century circulation patterns suggested that there would be much more westerly 900-300 mb shear in a big part of the Tropical Atlantic and over the southern half of the Caribbean, with less 900-300mb shear over the northern Caribbean and GOM then in our present climate. If this prediction were to come true, the net result for the U.S. might be fewer Cape Verde Type Hurricanes, but more powerful "home grown" hurricanes developing over the GOM. Of course it is a little early to asses the robustness of these model results. Still this example should serve to illuminate the uncertainties of severe weather in a warmer world, even in systems very sensitive to SST's.
Other forms of severe weather may be even harder to predict in a warmer world and the influences even more convoluted than for Atlantic Hurricanes.
I think that even If our present climate resembled say that of the 1700's, a lot of news would be about how crazy our weather seams to be both at home and abroad.
I will state here that I find it a little irksome that some members of this forum complain over and over about the global warming alarmists...one gets the impression that these people are so bothered by believers in Anthropogenic global warming that they feel depressed and feel like these people are literally sucking the life out of them and crushing moral !
What I Believe: I happen to believe that global warming is not just a fad and that the odds are that the planet will continue to warm over the next century or more and that even though there will be some desirable consequences, they will be outweighed by the negative ones.
Now for what I do not believe: I do not believe that individual extreme weather events can be blamed on global warming. In fact, the claims after every extreme event that it must have been caused be global warming are something that bugs me as well.
I also do not believe in blanket statements that there will be much more extreme weather of all kinds. Rather, a more reasonable statement might be that just like the prevailing climate, extreme weather will change as a result of global warming, with some types of extreme weather becoming less common while others become more common. Some examples of extremes may not show any obvious trend, but may change in seasonality or geographic occurrence.
To use just one example: Hurricanes are a believable candidate for an increase under global warming, as it is very likely that SST's will be warmer, but even here there are many ifs and buts. Warm Water is not enough to guaranty stronger hurricanes if problems like dry air ingestion and wind shear also change under Global Warming.
The Tropical North Atlantic seems to be a particularly complicated environment for hurricanes, with some negative factors such as hot dry Saharan air suppressing convection and adverse wind shear sometimes preventing hurricane development even over deep areas of very warm water that could serve as high octane fuel. Recent research suggests that during the latter part of the "little ice age" atlantic hurricanes were very active. Perhaps moister conditions in the Sahel of Africa and or favorable low 900-300 mb wind shear conditions were common, and made up for slightly cooler water. This finding suggests that we can not assume that warmer SST's in the tropical Atlantic will lead to more or stronger hurricanes.
One model simulation of late 21'st century circulation patterns suggested that there would be much more westerly 900-300 mb shear in a big part of the Tropical Atlantic and over the southern half of the Caribbean, with less 900-300mb shear over the northern Caribbean and GOM then in our present climate. If this prediction were to come true, the net result for the U.S. might be fewer Cape Verde Type Hurricanes, but more powerful "home grown" hurricanes developing over the GOM. Of course it is a little early to asses the robustness of these model results. Still this example should serve to illuminate the uncertainties of severe weather in a warmer world, even in systems very sensitive to SST's.
Other forms of severe weather may be even harder to predict in a warmer world and the influences even more convoluted than for Atlantic Hurricanes.
I think that even If our present climate resembled say that of the 1700's, a lot of news would be about how crazy our weather seams to be both at home and abroad.
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