View topic - Climate predictions, low water in Great Lakes for 20 years

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PostPosted: August 14th, 2013, 7:43 am 
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Predictions made by a recognized climatologist on North American climate patterns over several decades include western droughts and wildfires, and lowered Great Lakes water levels, with effects on economy (and recreation for canoeing here).

For the Great Lakes, a 50-60 year climate cycle corelates with rising and falling levels, in addition to any effects of climate change. The low water in Lake Huron and Georgian Bay today was matched by low water during the fifties... if this cycle repeats, then another twenty years of low water are predicted before lake levels start rising again.



Quote:
The New Normal — Some Expensive Consequences

Excerpted from The Browning Newsletter, August 2013, Vol. 38, No. 8

SUMMARY

From the Western wildfires to the Great Lakes, from insurance to transportation, real estate values, and fuel, the "New Normal" is having a major negative impact on certain sectors of the North American economy.

Long-term planning, using 20+ years of data, is biased towards climate conditions that no longer exist. If long-term planners look at 60-80 years of climate data, they should make different and better decisions.

Climate change is affecting the bottom line. The changes in two long-term trends are raising costs and cutting profits for a number of industries. As long as each bad year is accepted as a one-off, rather than the New Normal, these "unexpected" losses will continue.

• THE ATLANTIC – The waters in the Gulf Stream are flowing faster, carrying more hot tropical waters along US shores.

• THE PACIFIC – The Pacific has a 50-60 year cycle, called the Pacific Decadal Oscillation (PDO), that shifts warmer waters through the Northern Pacific. Starting in 1999 and tipping in 2006, the PDO has shifted cooler waters to US shores. Although occasionally interrupted by a warm El Niño, this creates drier Western weather.

...

Great Lakes Water Levels

The Western US is not the only region with low lake levels. Lakes Michigan and Huron set new record-low water levels last December, while the other Great Lakes dropped as well. Although some of this is due to the low snowfall levels of the winter of 2011/2012, the real problem is that the lakes have endured 14 years of below-average levels.

For the last 14 years, Great Lakes water levels have been severely reduced since 1999. This historically correlates to the negative PDO.

http://www.glerl.noaa.gov/data/now/wlevels/levels.html

There is no scientific literature that ties the lower Great Lakes levels to the negative PDO, but the two correlate historically. If the negative PDO is a large factor in reducing water levels, then these lower levels will continue another 20 years.

The economic impact of these falling levels is hard to overstate. The lower levels pose economic threats to numerous industries that rely on the lakes' water supply, including, shipping, electric, (especially hydroelectric) power generation, tourism, and recreational boating.

Both US and Canadian industries that rely on bulk materials such as iron ore, coal, limestone, and salt are hugely dependent on lake travel. Lakers move products at prices that beat rail or road by as much as $20 per ton of cargo. Lower lake levels, however, force ships to lighten their loads, making hauling less efficient. It is estimated, for example, that a large laker, 1,000 feet long, would ship 324,000 fewer tons per season for each inch lost from Great Lake levels.

The lower Great Lakes levels, combined with hotter summer temperatures, have had serious impacts on energy production. The cost of shipping coal has increased, and a recent Department of Energy study reports that multiple Midwestern electrical plants have been affected. Oil, coal, gas, and nuclear generators that depend on the lakes' waters for cooling have seen lower water levels and higher temperatures affect their efficiency, which in turn has raised the cost of electricity to consumers.

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PostPosted: August 14th, 2013, 9:14 am 
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The PDO is a total red herring.
Shame on that author for mentioning it in the same article as the present level of the Great Lakes. S/he places the same level of confidence in correlations as in scientific investigations.

There is a scientifically understood cause for the present low levels in the Great Lake, namely climate change (formerly called global warming, that formerly called the greenhouse effect) due mostly to increased levels of carbon dioxide in the atmosphere.

Here's a short version:
More carbon dioxide in the atmosphere warms the planet, on average. That's the greenhouse effect.
Due to the warming, ice forms on the Great Lakes later and melts earlier; as well, the ice covers a smaller area.
Water evaporates far more slowly from ice than from the liquid.
I omit a number of other effects; some decrease the effect and others enhance it. And there are feedback effects, both positive and negative. A detailed prediction requires extensive modelling.
But put those three sentences together and you come up with the following.
The result of the increased level of carbon dioxide in the atmosphere is then more water evaporating rather than staying in the lakes.

Please have a look at the IPCC (Intergovernmental Panel on Climate Change)
http://www.ipcc.ch/
report before claiming that the present low levels are just part of a cycle.

Here's an excerpt regarding the effects:
Lower water levels in the Great Lakes are likely to influence many sectors, with multi-dimensional, interacting impacts (Figure 14.2) (high confidence). Many, but not all, assessments project lower net basin supplies and water levels for the Great Lakes – St. Lawrence Basin (Mortsch et al., 2000; Quinn and Lofgren, 2000; Lofgren et al., 2002; Croley, 2003). In addition to differences due to climate scenarios, uncertainties include atmosphere-lake interactions (Wetherald and Manabe, 2002; Kutzbach et al., 2005). Adapting infrastructure and dredging to cope with altered water levels would entail a range of costs (Changnon, 1993; Schwartz et al., 2004b). Adaptations sufficient to maintain commercial navigation on the St. Lawrence River could range from minimal adjustments to costly, extensive structural changes (St. Lawrence River-Lake Ontario Plan of Study Team, 1999; D’Arcy et al., 2005). There have been controversies in the Great Lakes region over diversions of water, particularly at Chicago, to address water quality, navigation, water demand and drought mitigation outside the region. Climate change will exacerbate these issues and create new challenges for bi-national co-operation (very high confidence) (Changnon and Glantz, 1996; Koshida et al., 2005).

Incidentally, the greenhouse-effect alarm was sounded first by Alexander Graham Bell (he of the telephone).
http://en.wikipedia.org/wiki/Greenhouse_effect
In 1917 Alexander Graham Bell wrote “[The unchecked burning of fossil fuels] would have a sort of greenhouse effect”, and “The net result is the greenhouse becomes a sort of hot-house.”[14][15] Bell went on to also advocate for the use of alternate energy sources, such as solar energy.[16]

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PostPosted: August 14th, 2013, 10:11 am 
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I will add amonkeywrench. Lake Superior is running six inches ABOVE normal this year. No doubt climate is changing. Whether or not excessive and persistent rain is part of that or not


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PostPosted: August 14th, 2013, 10:26 am 
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Hey Allan, I agree that corelation does not imply causation. She does say that...

Quote:
There is no scientific literature that ties the lower Great Lakes levels to the negative PDO, but the two correlate historically.


So based on corelation alone, she is predicting that GL water levels will rebound after twenty years... I don't know that I'll still be around to see that if it does happen.

In the NOAA link she added above, Lake Huron water levels (chart below) were at times lower than post-2000, during a period from the 30s to the 60s... that might suggest some kind of cyclical rise and fall but there is a lot of variability from year to year, and some of that could also have been caused by dredging at the outflow.

http://www.glerl.noaa.gov/data/now/wlev ... hHuron.jpg

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