The dangers we face

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By Alex Waheed

The impacts on global climate change on the environment are often difficult to predict or imagine. New research, however, offers a glimpse as to how dramatic such changes have the potential to be.

According to Atlantic magazine (Oct. 16), new climate analysis methods prove that the Sahara Desert rapidly transitioned from a Serengeti-like environment into the most arid region on Earth about 5,000 years ago.

Researchers, led by Jessica Tierney and Peter de Menocal, analyzed decaying hydrogen and carbon isotopes in fossilized leaf wax buried in ocean sediments near the Horn of Africa to document the climate of the region during the past 20,000 years. The advantage of using such a method is that ocean samples are less susceptible than land samples to degradation by chemical and geological processes.

The most stunning find of their research is that this once-humid area became a vast desert in only 100 to 200 years, a relatively swift transformation on a geological time scale. Scientists believe this brisk transition was the result of positive feedback loops. The implications of this research are alarming; if desertification occurred so swiftly in the Sahara, how dramatically could today's world be altered, given the current trend of global warming?

Positive feedback loops in the environment will likely play a large hand in the near future, regardless of the causes of contemporary climate change, be they human induced or naturally driven. A positive feedback loop is created when the effects of a system are enhanced by the products of that system. For example, earning interest on a savings account and then saving that interest to earn more interest is a positive feedback loop.

In terms of climate change, melting ice caps constitute a major positive feedback loop. When ice in the Arctic melts faster than it is replaced the following winter, less sunlight is reflected, and an increasing amount of darker land or ocean is exposed to sunlight, causing further warming and increased melting of the ice.

Another example of positive feedback is the melting of permafrost. According to a New York Times article (Dec. 16, 2011), there are about 1.5 trillion tons of carbon frozen in permafrost in the Arctic tundra, which is around two and a half times as much carbon currently present in the atmosphere. As the planet gradually warms, the permafrost thaws, releasing carbon dioxide and methane into the atmosphere. Given that these are both greenhouse gases, their presence in the atmosphere will exacerbate the melting of the permafrost, releasing even more carbon into the atmosphere.

Other positive feedback loops exist, including potentially unknown ones, but the lesson is unmistakable. To avoid the dangerous effects of positive feedback, it is best to make an effort now to slow climate change rather than risk the dramatic change the Sahara underwent 5,000 years ago.

Alex Waheed is an Oak Park resident.

Reader Comments

13 Comments - Add Your Comment

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Degreed Environmental Engineer from Oak Park  

Posted: November 15th, 2013 12:09 PM

Brian: I don't have a bibliograpy to offer, but here's where I found the answer the question you pose below, easily found by googling Tierney and Menocal, Mr. Waheed's sources: "Green Sahara: African Humid Periods Paced by Earth's Orbital Changes". http://www.nature.com/scitable/knowledge/library/green-sahara-african-humid-periods-paced-by-82884405

Brian Slowiak from Oak parjk  

Posted: November 14th, 2013 4:27 PM

@ Degreed. Thanks for the broad base discussion and clear thought process.. If possible, please provide a bibliography of books that you have read to help me with this issue.

Degreed Environmental Engineer  

Posted: November 14th, 2013 3:10 PM

And Mr. Waheed is just cherry picking information and ignoring a 2012 article by the same authors he cites which states that the rapid climate change in the Sahara was due to a shift in the earth's orbit - hardly something we can do anything about. Such selective presentation (or more aptly: mispresentation) of the facts as a call to action undermines the credibility of those who DO make a valid scientific argument for antropogenic climate change and the possibility to do something about it.

Jim Coughlin from Oak Park, Illinois  

Posted: November 14th, 2013 2:21 PM

You are just parroting the talking points offered by those special interests who want the public to ignore scientific evidence and allow them to continue to poison our air, water and water without oversight or restraint. Check out who is funding the "research" and "experts" offering claims there's no need to worry. Don't turn a blind eye to the dumping of mercury and coal ash into Lake Michigan. We should not be asking future generations to cope with a toxic environment.. There are workable solutions but those might slightly reduce corporate profits so that makes doing something now totally unacceptable to those most responsible.

Uncommon Sense  

Posted: November 14th, 2013 2:02 PM

Jim, the science has not been "accepted". Much of the data has been fudged and alternate evidence ignored. No one is against conservativorship of the environment. People are against using unproven hysterics as an excuse to over regulate and tax industries. There have been warming and cooling periods throughout history, well before industrialization which brings to question the "man made" global warming.

Jim Coughlin from Oak Park, Illinois  

Posted: November 14th, 2013 1:40 PM

There's been great deal of concern expressed about future generations inheriting a huge federal debt. I agree that it is unfair to pass this burden along to our grandchildren and their families. Sadly, we may be leaving them with a poisoned planet. The individuals and multi-national corporations who fund climate change deniers are also directly responsible for the pollution of our air, soil and water. What motivates these special interests to challenge accepted science,ignore evidence and block any effort to clean up the environment? Greed!

W from Oak Park  

Posted: November 14th, 2013 12:39 PM

Simple solution to reduce CO2....plant more trees or get rid of all those humans that breath out CO2. The internet is a wonderful thing, I read that Alaska had it's coolest year in the last 100 years, same with Europe.

Degreed Environmental Engineer from Oak Park  

Posted: November 14th, 2013 10:45 AM

On a related note: I couldn't believe my eyes this morning when I saw one of those roving billboard trucks driving around downtown Chicago lambasting a certain media outlet as a climate change denier. I've always seen those billboard trucks as the ultimate symbol of wasteful, needless emissions, and here some misguided environmental group thinks this is the best way to get their message out. Looks far worse for the environmental group than the media outlet they were attempting to discredit.

Degreed Environmental Engineer from Oak Park  

Posted: November 13th, 2013 12:04 PM

While there may be a scientific basis for anthropogenic climate change, no evidence of it is given here to support the author's conclusion that action is needed. Quite the contrary: If there is an "unmistakable lesson" of the data quoted, it's that some climate change events have 'natural' causes (for those that don't consider mankind a part of nature).

Brian Slowiak from Oak Park  

Posted: November 13th, 2013 11:31 AM

About 5000 years ago within 100-200 years span the lush Sahara plain changed to desert. How and why did this happen and how did man, it all effect, the change?

OP Resident # 545 from Oak Park  

Posted: November 13th, 2013 11:25 AM

A wonderfully thoughtful response, MichaelO. Thank you for contributing great substance to the discussion. My background (BS in Enviro Science; MS in Chem) is quite opposite of your clearly knee-jerk reply. It gets frustrating when "climate junkies" spew random snippets of unrelated data, in a feeble attempt to claim some moral high ground. Again, this piece, while I'll recognize it took at least a little effort to create, made no substantive point. The planet is going to change. Duh!

MichaelO from Oak Park  

Posted: November 13th, 2013 11:11 AM

Alex, Nice piece. Disregard OP545. He appears to be a no-nothing reactionary twit.

OP Resident # 545 from Oak Park  

Posted: November 12th, 2013 11:23 PM

Great, Alex. Lots of unrelated factoids pulled from the internet, painting a picture of imminent doom, apparently for which we had no part in creating, & no chance of reversing. In other words, we're all dead. OK, thanks for that revelation. So much sound & fury signifying nothing. Next time, try to have something resembling a point. It's so much more interesting for the reader.

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