If we had used the dustbowl of the 1930s as an indication, how many people would believe that the Midwest has come back to be the most productive farmland in the world? For the very same reason, taking the last decade's temperatures and using them for a long-term climate outlook is unwise.
The dust bowl was mostly a 'man made' phenomenon. Too much clear cutting and poor agricultural methods in terms of planting and planning. They stripped the soil, tried to plant too much crop, and when the rains went away, you got the dust bowl because nothing was left to hold the soil. There was a natural reason that the natural Prairie Plants had roots that went 6 and 10 feet into the soil. It was to ensure they had a source of water because of the drought cycles. That's also what made the soil so fertile, it was 'deep'. With different planting methods, improved irrigation, etc the likelihood of a 'dust bowl' has been greatly lessened. Doesn't mean you don't get cyclical drought, but you're not seeing widespread stripping of the soil when the rains stop.
The reason the dust bowl happened in the first place was because of the deep soil that the plains states enjoy. The Department of Agriculture saw the potential of this 'natural resource' and helped farmers in the area improve their methods to keep it from happening again. I don't think there was ever any doubt in anyone's mind that the plains wasn't going to be the "Breadbasket to the World". This was probably one of the first examples of the Government enacting Environmental protection to keep this natural resource from disappearing altogether.
Nature love cycles. The fluctuations in the lake level is no exception. Sure dredging of outflow rivers has some effect, and that low levels will hurt shipping if they go lower, but saying they will never come up again is quite likely false.
There is a theory that the reason the Great Lakes level is dropping isn't necessarily because of a lack of rain, but rather "Crustal Rebound". The weight of the ice during the ice age compressed the tectonic plates that the Great Lakes sit on. This depression, helped keep the Great Lakes where they are. If you go back several thousand years, the shore of Lake Michigan was considerably further inland, so saying its dropped 6' in 150 isn't looking at the 'big picture' of it. It has dropped several hundred feet over 10,000 or 15,000 years, so 6 feet in only 150 could be a drastic increase in the levels dropping. So, without the weight of the ice and water on the plate, the magma below the crust is pushing the plate up. This forces the base level of the lake 'above sea level' further up, thereby causing more water to drain out of the lakes and towards the Atlantic Ocean. This natural 'rebound' may be part of the reason why the Great Lakes have been dropping. If that is the case, then it is likely that Great Lake water levels will continue to drop, and be extremely difficult to get back up to previous levels. Going to be tough to force that plate back down without some extreme weight on top of it to force it down. Problem is exacerbated because as you remove the weight of the water (drainage, evaporation, drought), there is less weight pushing on the mantle, therefore the rate of rebound increases.
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