Daisyworld was one of the first climate models that effectively demonstrated that rudimentary biological feedbacks can affect the global climate.
By: Daisyworld , 4:39 AM GMT on February 02, 2014
As we pass into the year of 2014 CE, I recall the first time that I discovered how much of a catastrophe the human race was facing when I picked up the January 1986 copy of Discover magazine in the mail:
Unknown to everyone at the time, our nation was in the waning days of the Cold War, with our attention more focused on an impending nuclear doomsday from a Soviet missile strike rather than the possibility of melting polar ice caps. The entire world had been primed to meet our ultimate fate for nearly forty years, so the Discover magazine cover didn't invoke the chilling effect in most people that it probably should have. "New York becomes the new Venice," I thought at the time, before jadedly tucking the mail under my arm and going inside to catch the evening news and the latest headlines on the continuing famine in Ethiopia.
Nevertheless, the image on the Discover magazine cover stuck with me, eventually leading me to study the article in earnest, mulling over how real the prospect was of a flooded United States coastline. I remember conferring with my grandfather about it at the time, who was a retired executive from global chemical manufacturing firm. "Do you believe everything you read?" he asked me. Well, no I didn't. Not everything, at least. However, I was more likely to believe a popular national science magazine rather than the Midnight Star tabloid on the grocery store news rack. The contrast between the two is a metric that can still be used today, though between much larger news conglomerates...
Two years later, the 1988–89 North American drought hit all of us by surprise, and I found myself holding onto that Discover magazine, reading and re-reading it, wondering and fearing what life would be like when the waters started to rise. The article cited the predicted temperature rise as follows: "(According to the models) after 1985 the temperature shoots upward, reaching 1° F in the early 1990s and almost 2° by 2000." This equates to 0.56°C in the early 1990s, and 1.11°C by 2000.
Source: Maranto, G., (1986, January). "Are we close to the road's end?" Discover, 28-50.
And indeed, the predictions were close. According to the Discover article, one of the models they cited used data from the University of East Anglia for the period 1851-1984. Taking the currently available CRUTEM4 data from East Anglia (source), the temperature anomaly rose to 0.59°C by 1995. While it appeared to plateau a bit afterward (excluding the 0.84°C rise in 1998), the temperature anomaly hit 0.9°C in 2007 and 2010, just 0.2°C shy of the 1986 prediction of 1.11°C for the year 2000. This averages to about 0.42°C for the entire 1990s (don't forget that the eruption of Mt. Pinatubo occurred during that time), and 0.75°C for the 2000-2010 period. Below is a "best guess" reconstruction I performed on the Discovery 1986 article (this is an "eyeball" guess from the image provided on page 39 of the magazine), alongside the current CRUTEM4 data, and with some data from NOAA tossed in for good measure (source):
The correlations are pretty good. Between the CRUTEM4 data and the Discover 1986 data, the R-squared was 0.94 (not bad for "eyeballing" it). Between the CRUTEM4 data and the NOAA data (using only the 1880-1980 timeframe because that's where the NOAA data started), the R-squared was 0.84. Lastly, the NOAA data and the Discover 1986 data had a correlation of 0.75. Perhaps the best comparison that can be made between these data sets are the slopes of the linear regression trendlines: They are all 0.004. This means the temperature trends between them are nearly identical. Oh, we can point fingers at the 0.14°C and 0.36°C offset in the Discover 1986 predictions for the 1990s and 2000s as much as we like, but the overall conclusion is the same: Temperatures spiked upward. Furthermore, the temperature fluctuations were some of the greatest seen since the last ice age according to Greenland Ice Core temperature data (GISP2):
In the above graph, the most recent (roughly decadal) temperature fluctuation that matched the average 1990-2000 trend of 0.42 occurred way back around the year 495 CE. The most recent one that matched the 2000-2010 trend of 0.75 was approximately in the year 9,291 BCE (this date is a very rough calculation to help establish a frame-of-reference). This annual was during the 10th millennium BCE, marking the beginnings of the Mesolithic and Epipaleolithic period in human pre-history, where the first inklings of agriculture were seen in the paleo-record, though most of the world's population of 1 to 10 million humans were still mostly hunter-gatherers. This 1,000-year period also marked the last major climatic shift the Earth has seen: The Younger Dryas stadial. This was a period of abrupt climatic change from a relatively warm, post-ice age period, back to glacial conditions in an interval of only 20 to 50 years... all well within the timespan of a human life.
The sudden onset of the Younger Dryas is as comparable in magnitude to that of it's effect on the planet: Forests turned to tundra, glaciers expanded down mountains, drought ravaged areas of the planet, and many animal species went extinct. The results of the Younger Dryas lasted for over a millennia in some areas of the Earth, and barely altered other areas.
Though the explanations for the cause of the Younger Dryas are many, with theories ranging from changes in ocean circulation to a cometary impact, humans were most certainly not the cause back then. Yet one thing was clear: After it happened, life was not easy.
While I do not hold to the prospect that we are headed towards another Younger Dryas, its impact on our planet should be a chilling reminder that nature's extremes are violent and common throughout Earth's prehistoric past, and often affects a wide swath of the biosphere. Most of all, we humans have barely experienced only a fraction of these extremes at any point during the course of our civilization. We should be concerned with the general rapidity and magnitude of our current climate change, precisely because the past extremes -- the ones that we know are coming -- have yet to fully manifest, and all signs point to things becoming worse.
Fact: Our climate is changing faster than at almost any point in our planet's 4.5 billion-year history. Fact: The decadal average global temperature swings that we're seeing now have never occurred at anytime during the course of human civilization. Fact: We caused this. No natural trend, no change in cosmic rays, no volcanic activity was the perpetrator of our predicament this time around. No other phenomena on Earth has converted such enormous natural stores of solid and liquid carbon within the interstices of our planet back into gaseous form through combustion. It was us; there's no getting around that.
As the past has shown, once rapid and abrupt climate change begins, we're left with few choices. The ecosystems that we've come to know and reply upon over the past several thousand years will change, most for the worst; today's fresh water resources will become unreliable as precipitation patterns shift, mountain glaciers will disappear, and surface freshwater reserves will dry up; sea levels will fluctuate and affect coastal communities; and just like the humans of the Younger Dryas, we all will be forced to make changes to our daily lives in order to survive.
The difference this time is that we know the change is coming. And as mentioned above, we've known for decades.
So, as the unknown future rolls towards us, we can guarantee that it's going to be a bumpy ride to our next climate equilibrium, whether that be another calamitous ice age, or another searing hot house condition. Lest we think it's a problem for tomorrow's generation, remember that the onset of the Younger Dryas took place within the timespan of a human life. Now, as the numbers add up and the predictions of the past point towards the trends of the future, we can either choose to face the onslaught of these extremes and prepare together for our common survival, or we can deny it and live our lives for only the moment of today, thus choosing the path towards extinction.
(Note: All calculations in this blog article were rudimentary comparisons constructed in Microsoft Excel with no actual peer review or statistical analysis performed)
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