There's a slight Autumn mist today. Just enough so you barely feel it, cool flecks on your face as you walk. Yesterday we had a drizzle. Several days before that a decent shower, carrying the musty scent of earth and water-steeped leaves, and a rhythmic ambient background to the usual cacophony that goes with a visit to the farmer's market.
I admit a fondness for rain. I write about it often enough. It's like another sibling. Something to bring comfort. Something to keep secrets. But here along the coast of Lake Michigan it has a darker side. The Lakes are evaporating.
If it seems by my stories like there is a lot of precipitation in Muskegon, part of it is due to my affection for the rain, and my particular focus on it. But part of it is also because there is more and more precipitation here...snow and rain.
The dark truth behind the precipitation in Michigan is a warming global climate. The evaporation that causes the rain also threatens to lower Great Lakes and other lake levels, damaging the ecosystems.
There are these bodies of water surrounding the State of Michigan, the Great Lakes, so vast they influence the weather. They cool and warm slower than the land so they lengthen the growing seasons along the coasts, making the productive West Michigan Fruit Belt a possibility: cherries, peaches, apples, pears, blueberries, plums flood the farmers markets by the bushelful in their various seasons. The Lakes also cool the summers, creating mild 80 degree days on the lee side, the windward side, of the water bodies.
The Lakes also produce what is known as Lake Effect Snow or Lake Effect Rain. Air sweeps across the vast body of water, picking up moisture and then dropping it on the land in the form of precipitation. It's this Lake Effect precipitation we're seeing more of.
Ironically, as the climate heats up, Michigan is going to see more snow. That's because when the lakes freeze in the winter it usually restricts the amount of moisture the winds can pick up as they cross. But the lakes haven't been freezing as much, due to warmer winters. It leaves more liquid water exposed, so the winds evaporate more of the water from the lake and dump more of it onto the land. Worse...some of the water vapor is carried far away on the winds, never to return to the water shed, slowly evaporating the lakes over time.
A recent hydrologic modeling study tells us that precipitation has increased by 6% since 1940
Observations across the watershed show long-term trends of increasing temperature and precipitation during the 20th century. These two trends have altered the hydro-logic cycle in the MRW in a variety of ways.
There have been significant trends in precipitation over the last century in areas that receive lake effect precipitation. For example, Big Rapids experienced a 6% increase in precipitation from 1940 to 2001
The greater threat here is the dropping water levels of the lakes. Dropping water levels threaten wetland ecosystems, the wildlife they harbor, and the natural flood protection and filtration they offer.
Global warming will drop the Great Lakes water levels. It's already happening.
It seems counter-intuitive to many that the Great Lakes water levels would drop while the oceans are rising. But the Great Lakes are far above sea level. By and large they won't be affected by the rising of the oceans. They WILL be subject to increasing evaporation, however, as the weather heats up.
Note the lighthouse that used to be on the shoreline.
This year the water levels were up, after several years of record lows. Water levels are cyclical. But that didn't stop global warming deniers from crowing about how an uptick in water levels disproves Climate Change. I have a diary about that, if you'd like to read it. But in the end, the study cited by the global warming denier in question flat out states that climate change is real...
In its most recent assessment, the Intergovernmental Panel on Climate Change concluded that scientific evidence based on well-established theory and observations from long-term monitoring networks indicates that climate change is occurring, though the effects differ regionally (Brekke et al., 2009). The Intergovernmental Panel also noted that climate trends since about 1970 have been driven predominantly by greenhouse gas concentrations in the atmosphere and that this will
continue to be the case in future decades.
Most environmental studies show the Great Lakes levels dropping even as precipitation climbs
"Climate projections say the lakes will go up and down around a decreasing average," said Don Scavia, director of the University of Michigan's Graham Environmental Sustainability Institute. "The lows will be lower than in the past and the highs will be lower than in the past."
Article
Now...I say all this, not to rain on anybody's appreciation of the rain, but because each raindrop should be a reminder of how urgent global warming is, how it's affecting our world Right Now. It's happening at an ever increasing rate, and we are witnessing its effects Right Now.