When Are We Due For It?

History has seen the rise and fall of many large and powerful cultures. Romans, Mayans, Akkadians, none of these historic empires have lasted in much more than memory and artifacts. But their decline and eventual disappearance is often a source of intense study and speculation, since many of them don't have clear records of their declining years. However, recent evidence has shown correlations between shifts in the local climate and the disappearance of these large civilizations.

The Mayan empire existed in Central America for around 2000 years before it faded back into the mists of time. The reason? Well, that is still a matter of speculation, to some degree. However, there are some theories that are particularly prominent.
"Some believe that by the ninth century the Maya had exhausted the environment around them to the point that it could no longer sustain a very large population. Other Maya scholars argue that constant warfare among competing city-states led the complicated military, family (by marriage) and trade alliances between them to break down, along with the traditional system of dynastic power. As the stature of the holy lords diminished, their complex traditions of rituals and ceremonies dissolved into chaos. Finally, some catastrophic environmental change--like an extremely long, intense period of drought--may have wiped out the Classic Maya civilization. Drought would have hit cities like Tikal--where rainwater was necessary for drinking as well as for crop irrigation--especially hard."
 If you take some additional time to look at these theories, it is easier to see that they could all be part of the same sequence of events. If we start with the drought, then that would lead to the exhaustion of agricultural supplies and means, as well as drinking water and possibly a primary means of transportation. No longer able to sustain the population that exploded with the preceding period of high rainfall and agricultural windfalls, the land began to lose potency, and the people began to suffer. This situation usually leads to civil unrest, and considering the leaders of the culture were also holy figures, they might even be seen as part of the cause of the people's misery. This would lead to the breakdown of government and trade alliances, as people stop listening to distant authorities, and start keeping supplies that might have been previously sent to the capital. As you can see, these possible causes don't have to be mutually exclusive, and in fact become more plausible when combined. This particular series of events has seen increased scientific evidence to its viability as well, with the time of the drought correlating with the time frame of the Mayan civilization's decline. As this hopefully demonstrates, a shift in the climate patterns can have a sudden and drastic impact on a society, to the point that it collapses.

Another example of such shifts in climate causing a societal collapse is the Indus (or Harappan) civilization that was established in the area of modern day "Pakistan, northwestern India and eastern Afghanistan." However, climate shifts also contributed to the establishment of the civilization, since the region was formerly inhospitable due to extreme weather and flooding that was strong enough to sweep away what people would try to build. However, as the monsoons responsible for this extreme weather became more gentle over the years, the flooding became gentle enough that it became an integral part of the farming process in the region. However, this process continued instead of halting in this "Goldilocks status," and since the river that supplied and nourished the region was apparently only fed by rain, with no large body source, the decline in rainfall also meant a decline in available water. In this case, as the river dried up, many people moved to other regions. Some were able to continue farming, since the rains still came, they just would not have been able to produce enough food to feed the city populations that had peaked during the prosperous period of the civilization's history. In this case, the fall of the civilization was a matter of time and circumstance. Unfortunately, without much cause to notice the gradual (oh so very gradual!) change in the weather patterns over the years, and no records to provide a warning (writing was developed during its time, but not from the start), the civilization was doomed to fall as the climate continued its drying trend. So, it becomes difficult to blame the fall of the civilization on their lack of foresight, when they didn't have much hindsight either. Besides, the society lasted for around 2000 years, which would probably span hundreds of generations of people, who didn't have any reason not to take advantage of such a pleasant, fertile region. At least their activities (supposedly) didn't contribute to the climate shift, since it was already part of an established trend.

Which brings up my last point- if a society can collapse due to climate shifts that are already occurring due to shifts in global temperature currents and the like, what will happen when something like this happens on a global scale? Unlike the Harrappans, we won't have anywhere to go if we are managing to afflict the climate processes of entire regions of the globe. We have already seen some of the warning signs of radical changes in the weather- the drought over the summer, Hurricane Sandy's impact on a region that normally doesn't see such violent weather, and generally rising temperatures. Unlike the civilizations of the past, we can tell what is driving the shifts in the climate now- heck, we can even identify contributing factors to their climate shifts. The question is, will we do anything about it, to prevent a permanent shift in global habitability, or will we simply continue along our current path of self destruction?

Extra links:
Roman Empire studies
http://www.groundwatergo.com/blog/the-top-5-ancient-civilizations-destroyed-by-climate-change/
Decline of Akkadian Empire at start of 300 year long dry spell

Can Coal Be Clean?

Clean coal is kind of a pipe dream. It's pretty much a rock that can be burned, and since it can be burned without any kind of purification process (in fact, I'm not sure if you can do anything to purify a solid like that) it is bound to have all sorts of nasty things, like heavy metals, mercury, arsenic, sulfur dioxide (which is one of the worst ingredients for acid rain) and the like. That's not even mentioning the significant quantity of CO2 that is released from burning coal. Most so-called "clean coal" tech has focused on removing the toxic compounds and dangerous particulate from emissions, and to a lesser degree reducing CO2 in emissions. In the past, coal burning plants used to respond to complaints in the local communities about their smoke and dust by making their smokestacks taller, thus making it so that the smoke and gasses would be blown further away from the local populace... thus spreading the problem into a larger area, and affecting more sensitive habitats. Nowadays, they try to improve filters and carbon capturing systems, which is only mitigating the larger problem. And while it is just about impossible to burn something that doesn't produce CO2, the sheer quantity that coal is able to produce gives it unique status as an especially dirty pollutant.

Something that may have an impact on how coal can be used is a method known as the Fischer-Tropsch process. It is a process that can be used to make liquid hydrocarbons from pretty much any combustible carbon-containing compound, such as biomass, natural gas, and coal. It does so by first generating carbon monoxide, then combining it with hydrogen. The process was first discovered by German scientists during the 1920's, and was subsequently used to convert coal to liquid fuel during WWII to power German war machines. While CO2 is still produced during the production and combustion of Fischer-Tropsch fuels, it can be captured more easily in the lab, and the other pollutants can be stripped from the gas stream during the production process as well, thus making a cleaner burning fuel. The process has been considered for mass use several times throughout US history, though economic aspects usually brought any advancement to a halt. In fact, some of these events may have been engineered to some degree: "The last time investors started lining up money for Fischer-Tropsch plants, in the 1970s, the OPEC oil cartel opened up its spigots and pushed the price of crude down to $10 a barrel, and that was that". Meanwhile, South Africa has based the majority of their fuel consumption on Fishcer-Tropsch fuels produced from local coal deposits. While it isn't the best alternative to petrol based fuels in terms of CO2 emissions, synthetic fuels are comparable in power, have fewer side products, and in some ways are easier to obtain than oil. After all, we would be able to make it from local sources, instead of having to import most of the ingredients.

While there wouldn't be a need to import most of the materials for Fischer-Tropsch fuels, and they can arguably be made cleaner than many current petrol based fuels, I would be remiss to overlook the aspect of how coal is obtained (though the making of such fuels from biomass would be a nice way to take care of garbage disposal at the same time). One of the greatest impacts coal has on the environment, while it has a more localized effect than the spreading of emissions, can be the mining of the coal from the ground. Whether it's shaft mining, strip mining, or the charmingly named "mountain top removal," there is usually some sort of impact on the surrounding area. Shaft mining, while there seems to be a relatively minimal effect on the ecosystem, can be dangerous work. And while one may think that the shaft is usually left behind after the work, most modern projects fill in the shaft after they leave to prevent some sort of collapse on the surface when the tunnel supports give. Strip mining leaves a massive gouge in the earth, which nature will be slow to reclaim due to the solid rock surfaces left behind with development, and often the rock that they can't use just gets dumped into nearby areas, managing to kill off another area, or perhaps blocking a source of water for a region and spreading the devastation further indirectly. Perhaps the one way this could be made productive is if someone found a way to make a city in the walls, kind of like the ancient city of Mesa Verde. But then, mountain top removal is just destructive, and unfortunately cheap enough that companies will use it anyway. So, even if we found a way to make synthetic fuels with coal feedstock, there would be the issue of how we would obtain it without causing more direct destruction than the insidious elements from the burning of fossil fuels could hope to match. In fact, it may compound the issue, as there would be less living plant biomass to take up the CO2 being produced.

Whatever the case, the one thing that is easiest to take from what I've learned is this: If there's a trick to clean coal, it is to not burn it as coal.

Extra links:
http://www.afdc.energy.gov/pdfs/epa_fischer.pdf 
http://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_process
http://www.economist.com/node/13235041?story_id=13235041

Rainy Days... is the drizzle smoking?

To me, acid rain seems like a highly unpleasant concept. Rainwater, usually one of the most reliably clean sources of water on earth, becoming caustic enough to increase erosion rates of stone and metal. Also, changing the soil of the plants that it waters in such a way that they die off, and few things if any are capable of growing in the ground thereafter. It just seems wrong, like a perversion of nature in a way; one of the most necessary elements in biological systems, and an invaluable delivery system for cycling and delivering water to regions where it doesn't last long on the surface, becoming a vector for killing off otherwise hardy ecosystems. It's a twisted version of the cycle that is so necessary for life.

While rain itself is naturally more acidic than neutral due to naturally occurring weak acids generated from atmospheric gases, it usually falls within a certain range that organisms have evolved to operate within. If the natural acidity is pushed too far, or reduced to a basic nature, organisms typically suffer from various functions becoming inhibited as the proteins and enzymes within the cells of any organisms subjected to the changed pH become inert or inoperable, if they aren't killed outright by possible corrosive effects. Plants that don't suffer from effects such as these are often victim to either toxic compounds being solvated and absorbed, or to atrophy as vital nutrients are dissolved to the point that they flow away before they can be taken up (http://www.epa.gov/acidrain/effects/forests.html). Bodies of water are also subject to such sensitivity, with similar reasons- fish are susceptible to poisoning by aluminum and acidic conditions, while microorganisms suffer from their medium being changed (http://www.epa.gov/acidrain/effects/surface_water.html).

It's not just the environment that is degrading due to acid rain, either. Various man-made structures are subject to damage from acid rain, especially those made from rocks primarily composed of calcium carbonate, and ferric and cupric metals. "Calcium carbonate in certain stones dissolves in dilute sulphuric acid [from rain] to form calcium sulphate." (http://www.air-quality.org.uk/12.php) Calcium sulphate, often known as gypsum, is a much more brittle stone, and is subject to falling off of the afflicted stonework, leaving an exposed area that is subjected to further reaction with acid rain. Besides the effects upon statues, various buildings of note are feeling the effects, including the Taj Mahal, Notre Dame cathedral, and the roman Colosseum.

Acid rain is generated in various ways, some natural. However, natural acidity is usually caused by carbonic acid, a much weaker acid than the sulfuric and nitric acids that typically causes problems. These are often generated by the release of industrial chemicals from smokestacks, or from the exhaust of motor vehicles. Though both can occur naturally, the quantity of these compounds in the air has increased and been generated more frequently, as compared to being generated from less common events such as wildfires and volcanic eruptions, which combined produce roughly 1/7th of the quantity of sulfur dioxide released from human activities per year. And while the phenomenon is typically referred to as acid "rain," it doesn't necessarily need to come down in aqueous conditions- sometimes these acids occur in gaseous or solid forms and reaches the ground long enough to either stick to something or react with something. When this happens, it's usually referred to as dry deposition. However, it's effects can be just as much, if not more noticeable in the long run, since the quantity deposited will most likely be fully unleashed when exposed to water, and when that occurs, the dry material will solvate and add up to a much higher concentration being administered all at once. When this happens, the pH drops even more dramatically, and the organisms subjected to this treatment will most likely not be able to cope. And while humans may not be susceptible to direct health effects from increased acidification of the environment, it is the gaseous and dry particulate that can cause various severe health issues, as these will dissolve in the mucous lining of the respiratory system, and cause heart and lung problems.

Unlike climate change, this matter has received political attention and study, though not without it's own share of political turmoil. In 1980, a program was put together to try and assess the extent and impact of acid deposition on the environment. This program was called the National Acidic Precipitation Assessment Program(NAPAP), and was supposed to perform a long-term study into the matter of acid precipitation and it's effects on the environment, and come up with a "credible evaluation of the consequences of various policy options"  While it seemed to serve it's purpose by the end of it's term, although "advocates from all sides attempted to use the program to support their own policy marketing efforts, or to disparage those of their opponents." (http://www.epa.gov/wed/pages/staff/lackey/pubs/ACID-RAIN-SCIENCE-POLICY-LACKEY-BLAIR-JOURNAL-REPRINT-1997.pdf). Another study, by the DENR, found in 1991 that large bodies of freshwater are becoming more acidic, enough so that some species of fish can no longer survive within them. Meanwhile, the Clean Air Act was passed in 1989, which introduced the concept of "cap and trade," a system where permits are issued for how much of a pollutant gas can be released into the atmosphere by a company per year, and if they don't expect to reach that limit, they can trade those permits to another company for something. This allows for companies with the means to make the large scale changes to their operating facilities to clean their emissions can do so, trading to the companies that don't yet have the capacity to do the same until they do have the capability. It seems to have been a success for this program, and apparently at a lower cost than was initially expected. However, the success may be attributed to certain changes in the industries that were actually subject to exuding the compounds responsible for the acidity in the air. A similar system is being proposed to try and handle greenhouse gases, but part of the reason they are so hard to handle is that they aren't as reactive as sulfur dioxide, and can be harder to contain. There is also the matter of the time that such a plan needs to be effective, as gradual changes come about; climate change is already at an advanced stage of progression, and if this program even had a chance to work here as well, is it too late to help? But that is a different matter.

While sulfur dioxide emissions by human activity haven't been reduced to zero, they have been reduced significantly, perhaps even to the point where our impact on the environment through that vector is minimal. Hopefully our impact will be less than those of natural causes one day, but in the meantime, it's good to be able to celebrate our victories while we can... as long as we don't backslide in the process.