Posted by jlwile on December 8, 2011
As I have mentioned previously (here, here, here, and here), the earth has a wide array of negative feedback mechanisms that help it cope with change. This, of course, is exactly what you would expect for a system that was designed by an incredibly intelligent Designer. Unfortunately, many people who study the earth don’t understand these negative feedback mechanisms or don’t appreciate how incredibly powerful they are. As a result, they overstate the severity of certain trends that scientists observe. One excellent example of this comes from the observation that in recent years, the amount of sea ice in the Arctic has dropped significantly.
In the graph above, a 21-year average of Arctic sea ice extent is shown with the heavy gray line. The gray band that extends above and below that line shows the variation one would expect from random fluctuations. Now look at the green dashed line. That’s what was measured in 2007. Clearly it is far, far below the average, and it is well below what you would expect from random fluctuations. As a result, the drop in sea ice is probably the result of a systematic change that is occurring in the Arctic. Not surprisingly, some doomsayers went off the deep end when they saw such data.
One research team told an American Geophysical Union meeting that the Arctic could be ice-free by the summer of 2013. In fact, they claimed that this estimate came before the sea ice extent was measured in 2007, so it might be a bit conservative! Al Gore, in his 2007 Nobel Prize acceptance speech said:
Last September 21, as the Northern Hemisphere tilted away from the sun, scientists reported with unprecedented distress that the North Polar ice cap is “falling off a cliff.” One study estimated that it could be completely gone during summer in less than 22 years. Another new study, to be presented by U.S. Navy researchers later this week, warns it could happen in as little as 7 years.
Obviously, it looks like the doomsayers were wrong. While 2007 was an incredibly dramatic year of low sea ice in the Arctic, the trend hasn’t continued. Instead, 2008 saw a marked recovery of sea ice, and while 2011 has less ice than 2008, it still isn’t as low as 2007.
Why did the loss of sea ice seem to halt after its precipitous drop in 2007? Why weren’t the doomsayers correct in their prediction of a rapid drop in sea ice that would eventually lead to no summer sea ice in the Arctic in the very near future? Most likely, because of one of the many negative feedback mechanisms with which the earth has been designed. In fact, J.‐É. Tremblay and colleagues might have even uncovered which negative feedback mechanism is at play here.
They surveyed the Arctic in 2007 and 2008, and they found that as the sea ice retreated, many organisms in the Arctic such as ice algae, phytoplankton, and zooplankton started increasing the amount of photosynthesis they were doing.1 After all, as the ice went away, more ocean was exposed to sunlight. In addition, the climatic changes that caused the loss of sea ice also caused changes in the local ocean currents. These changes brought in nutrients that the Arctic organisms needed to increase their photosynthesis.
Of course, photosynthesis takes carbon dioxide out of the atmosphere and replaces it with oxygen. Thus, if atmospheric carbon dioxide really is driving an increase in the temperature of the Arctic, the increased photosynthesis caused by the retreating sea ice and the changes in the ocean currents ended up reducing carbon dioxide levels. If this is really what happened, it is a classic example of a negative feedback mechanism, and once again, it demonstrates how well-designed the earth really is.
Now I personally don’t think that carbon dioxide is driving the loss of sea ice, but I am still willing to believe that the change in photosynthesis rates could reduce the melting of the sea ice in some other way. If nothing else, the energy of sunlight that is absorbed by the photosynthesizers can’t be used to increase the temperature of the surroundings. Instead, it is used to make glucose. Thus, increased photosynthesis itself could result in a reduction of local temperature.
The main point here is not how increased photosynthesis might reduce sea ice loss or even if increased photosynthesis reduces sea ice loss. The point is that when the Arctic loses sea ice, lots of other changes occur. Tremblay and colleagues have found one process that has changed. There are probably lots of others. Since we know the earth is incredibly well designed, it is reasonable to conclude that at least some of those changes are part of earth’s elaborate negative feedback mechanisms which make the earth a very, very robust environment.
If we honestly look at the scientific data we have, it is clear that the earth has been designed with a lot of forethought. As a result, rather than flying off the handle as soon as we see the earth undergoing a systematic change, we should think about the negative feedback mechanisms that exist in any well designed system. If we do that, we will lose the hysteria and will be able to concentrate on serious scientific analysis.
1. J.-É. Tremblay, et al., “Climate forcing multiplies biological productivity in the coastal Arctic Ocean,” Geophysical Research Letters 38:doi:10.1029/2011GL048825, 2011
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