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What a brown patch of lawn can teach us about global warming

This perfect crescent of brown lawn shows evidence of a microclimate, a definitive illustration of macroclimate principles.
This perfect crescent of brown lawn shows evidence of a microclimate, a definitive illustration of macroclimate principles.
Christopher Cudworth

In our front yard here in Illinois there is a perfectly shaped crescent of dormant grass. The brown patch exactly follows the shadow pattern of a giant sycamore tree to the south of our yard. The grass beneath this sycamore has hung in there through a summer of drought. But where the sun strikes unimpeded, the ground surface suffered.

One morning while leaving to walk the dog, it struck me: This is a microclimate. This is exactly how microclimates work.


If you are not familiar with microclimates, they can exist anywhere. A microclimate is an environmental circumstance in which varying factors of temperature, wind, sun, moisture, topography and plant and animal activity combine to generate an ecosytem that is unique amid the greater climactic conditions that generally rule an area.

For example, the north-facing side of a steep bluff in northeast Iowa may contain plant communities that are highly dependent on the moisture content of the soil, evaporation, lack of sun and ground water levels that combine to create a hydro-dependent plant community and other biota that depend on it.

That microclimate will likely stay the same, sustaining plant forms and other life that do not exist within the greater ecosystem for as long as the general conditions dictating the north-facing bluff remain the same.

But if the bluff were to be timbered, removing all the birch and cedar trees and undergrowth shrubbery, that community could be radically disturbed. Plants that depend on high moisture levels and shade might wilt and disappear. The chain reaction among other living things would also be impacted, from birds to ants to amphibians living in the moist climate under the trees on a north-facing slope: All might disappear.

Climate factors

So it struck me that a suburban lawn was essentially subject to the same microclimate factors that affect complex communities like that bluff in northeast Iowa. The fact that suburbanites prefer monocultures of grass to diverse prairie vegetation in Illinois is simply a reduction in the overall equation. But it still holds true. Our microclimates in Illinois are much more illustrative in a way than a misty bluff in Iowa. You can see the effects almost in black and white.

Or brown and green, as the case may be.

As illustrated by the photo attached to this article, you can see the results of summer shade cast by the sycamore tree as clear as yin and yang in the brown zone in our lawn. This is not the result of water, but of exposure to a relentless summertime sun that parched not only our lawn, but 63% of the United States suffering the worst drought since 1988.

Lessons from the 1988 drought

The results of that 1988 drought were profound here in Illinois as well. Early that spring, before the drought took effect, a group of us birders were out surveying warblers in May. It was a challenge to hear the songs of the birds over a large chorus of frog species singing from shallow ponds at the north rim of an Illinois forest preserve. Chorus frogs, spring peepers, green frogs, leopard frogs and American toads were all singing so loud you could hardly hear the warblers in the oak grove next to the marsh edge. I clearly recall a woman named Dorothy Brownold, a delightfully distracted lover of nature trying to get us all to forget about the birds for a minute and listen to the frogs and toads.

By the next year, the marsh was completely silent in spring. No frogs or toads survived the massive drought that hit not long after that May chorus rang out. Ponds dried up completely, choking off successful breeding. Cracks formed deep into the peat and mud of the marsh. Lake levels seeped away as well. The drought did not break until well into September that year. By then it had profound effects on local climate.

That next year no frogs at all could be heard singing come spring. And they have never come back. That was 24 years ago.

Larger climate change

We hear warnings of major climactic changes due here in Illinois over the next 20 to 50 years. One writer speculates that the climate in Illinois will someday soon resemble that of New Orleans in terms of heat and humidity. Would be that we were so lucky. Other climate models predict a 100-year drought equal to that of 1988. We got a dose of what drought can do in the short term here in 2012. Millions of acres of corn and soybeans are about to be plowed under in southern Illinois. We got enough rain to perhaps save a few farmers here in northern Illinois, but across much of the Midwest, soils are parched. Dry. Unproductive. Crops have been killed off by drought.

It wasn't that long ago that drought conditions coincided with tough economic times in America. During the Depression the Great Plains became a Dust Bowl. People struggled to survive because the soils were turned over too rapidly and drought conditions took hold so quickly there was no stopping the massive climactic shift that ensued. Dust killed people. Piled up in drifts. Blew in dust storms. Gutted America's wheat crops. It took years of government intervention and vegetative restoration to rescue and repair the Great Plains.

Warming trends

Industrial farming now reigns across not only the Great Plains, but the more temperate Midwest as well. It is easy to assume the Dust Bowl could never come to Illinois. But the 2012 drought is a reminder that no one is safe from broad-based climactic change. We had one of the warmest winters on record here in the Midwest. Now we've had one the hottest summers, with months of 90+ temperatures and no rain for weeks and weeks. In fact the last 10 years combine to form one of the hottest decades in all history.

When it did rain this year, the winds that arrived tore trees from their roots. The sycamore next door in our yard is showing the strain of its age. It has a giant gash up its side, perhaps the product of the drought, or the stress of holding up against major winds. Should it come down, the entire microclimate it generates for our yard would be changed. My wife would cheer of course. She hates the tree. It is messy and its big leaves come down so late in fall we can never seem to rake them up in time for winter. So we normally finish the job come spring. But this winter was so warm and snow-free that we easily raked up the last of the sycamore leaves on a calm, warm day in December. That mostly creeped us out.

Ideology versus patterns in nature

People with common sense (not even scientific training...) can see the relationship between the dynamic evidence of microclimates and the bigger climactic changes going on in the world. Just as the patterns of alluvial erosion in the childhood dirtpile mimic the flow of alpine debris down a mountain, people without arrogant presumptions or ideological preconceptions know that the little things we see happening around us directly reflect the bigger picture of global climate change.

All it takes is basic study of our solar system to realize that Earth occupies a unique niche in the universe. The conditions for life here really are fragile. For the most part, they do not exist on Venus, Mercury or Mars, the nearest planets to Earth, for their conditions are either too cold or too hot to sustain plant and animal life, the vital mixture for human existence.

We've begun to look deeper into the universe with massive, space-borne telescopes to scout for planets that resemble Earth, but as yet we have not found any. To the profound disappointment of Chewbacca fans, we must acknowledge that the fantasies wrought by Star Wars are an intensely dangerous lie.

Simple changes--too hard from some to conceive?

We have just one Earth and one fragile climate to depend upon. The hopes of space travel to another galaxy are just pipe dreams. The practical response of backing off on just our most egregious behaviors in burning fossil fuels unrelentlessly are by comparison a simple act that would protect our humble lifestyles, prevent our atmosphere (just 7 miles thin!) from becoming too weak or poisoned, and from creating conditions where earth could overheat, turning our whole "frontyard" into something parched and useless like the corn fields we are now plowing under.

So here's the truth if we regard our position in infinite space with any perspective of maturity at all, we recognize that the Earth itself is a microclimate, subject to the same risks and quick vanishings as any microclimate within the whole.

Supposedly astute economists and ideological thinkers of a largely "conservative" bent keep trying to tell us that global climate change is an impossibility. These climate change deniers cite economics as the most important factor to consider when legislating auto and/or industrial emissions standards. Yet economists cannot even predict the next quarter of financial results with any sort of accuracy or consistency, so why should we trust such flighty minds to dictate the future of the human race, and perhaps earth itself?

It only took one silent spring devoid of frogs for this author to realize that microclimates are models for macroclimates. The earth is not too big at a macro level to reflect the critical failures we see at the micro level. In other words, people like Rush Limbaugh are pathetic blowhards without a clue about how nature actually works.

Systemic failures

Perhaps it is the failure on the part of such people (and their politics, and their religion) to understand even basic evolutionary theory, or to acknowledge the simplest patterns of geology and earth history to teach us that the "little" climates we observe are directly related to the "bigger" climate of Earth. The earth's climate is not so big if you undertstand that we are a tiny speck in a massive system driven by universal change. It is all about energy, heat and laws of thermodynamics. As a result, some insist that earth is too big for mankind to affect in terms of climate. But if a mile-long asteroid striking earth can screw things up enough climactically to kill off the dinosaurs, it stands to reason that a population of 7 billion human beings kicking out exhaust fumes and other pollutants can do just as effective a job.

Or are we too perfect in our makeup to make a mess of things. Are humans beyond reproach? Somehow the climate deniers seem to think we are immune to the pains of our own actions. But even the Bible tells us we are not. Original sin has no limits set upon it, and if humans can screw the pooch on a place as nice as Eden, we can surely mess up the rest of earth as well.

Every time we walk out onto a brown patch of lawn, we should not forget how fast it all can change. In the twinkling of an eye, really. The signs are right before our eyes.


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