Scenario: How does a railroad operate when the ground underneath is melting? Actually the question might be academic, as this railroad has long since been abandoned. The 196-mile Copper River Northwestern Railway was built in 1908 after copper was discovered in what came to be known as Alaska’s Copper River Valley. The railroad has survived encroaching glaciers and earthquakes. Even when it was built, it was referred to as the “roller coaster railroad” due to the uneven settling of the railroad bed caused by melting of the permafrost beneath.
Now other Alaskan infrastructure faces threats from permafrost melting. The Trans-Alaska pipeline is in danger of shifting due to possible melting of the permafrost over which it was built. The Arctic is experiencing some of the most rapid and severe climate change on earth. According to the Arctic Climate Impact Assessment (2005), “over the next 100 years, climate change is expected to accelerate, contributing to major physical, ecological, social, and economic changes, many of which have already begun. Changes in arctic climate will also affect the rest of the world through increased global warming and rising sea levels."
What exactly is permafrost? It is frozen soil that remains at or below 0 C for at least two consecutive years. Permafrost regions occupy about 20 to 25 percent of the world's land surface, and in parts of northern Siberia, permafrost can be up to a mile (1,600 meters) thick. Permafrost can stay frozen for thousands of years. The layer of soil that sits on top of permafrost and thaws during the summer is called the “active layer.”
In subarctic Sweden, the active layer has been getting thicker since 1970 and in some cases, the permafrost has disappeared. In a 2004 study reported by the GeoBiospheres Science Centre at Lund University in Sweden, it was noted that methane emissions from bogs or mires were increasing by at least 20 percent. This increase was due to the release of methane from the decomposition of plant material under wet, rather than frozen, soil conditions. Global warming and the melting of permafrost has scientists concerned about the amount of greenhouse gases that will be released into the atmosphere.
The melting of permafrost and other changes at the poles, if continued, could have great environmental, social and economic impacts. Is this threat real? Here is an excerpt from the Hydrogen Now Journal:
“So, does methane pose a threat today? Let us review the situation. We know there are extensive methane hydrate and permafrost deposits all around the world. We have evidence that we are at the beginning of a period of global warming that is probably being made worse by the continuing build up of CO2 in the atmosphere due to fossil fuel burning. Recent computer modeling incorporating the feed back effects of global warming that has already occurred suggests that by about 2050 we may start to loose the beneficial effects of the Amazon rain forest as a carbon sink. This could lead to temperature rises of 5 to 8 degrees centigrade by 2100. This would be uncharted territory and no one really knows at present how the world's environmental systems would change but we now have the evidence from the geological past. On the basis of this evidence global warming can lead to methane releases which once started would escalate. This would be the worst possible thing to happen because once started there would be no way of stopping a runaway methane global warming event. We CAN reduce our CO2 emissions from fossil fuels but we COULD NOT reduce methane emissions once they started, huge natural forces would take over and change our world. This would probably result in the melting of the Antarctic icecap which would raise sea levels by 50 metres and would completely change the climates of the world.”
Others are not so sure and are less worried. Here’s an excerpt from an editorial written by Dr. Richard Lindzen, a professor of meteorology at MIT:
“Over the last 100 years or so, globally averaged surface temperature, which is always varying a little, has gone both up and down, but over the whole period it is estimated to have risen about half a degree centigrade (using the US National Climate Data Centre's analysis; other analyses give as much as 0.65C). However, this value is associated with substantial error bars, and the warming is occurring in a system that can vary about that much without any forcing at all - something not surprising in a system that is both turbulent and heterogeneous. Yes, there does appear to be warming, but the amount is hardly certain or indisputable. And the amount found does not appear that alarming. The alarm, I would suppose, comes from the notoriously inadequate climate models.”
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Scenario Images
Tens of billions of tons of carbon move between the atmosphere, hydrosphere, and lithosphere each year. Human activities add about 5.5 billion tons per year of carbon dioxide to the atmosphere. The illustration depicts the total amounts of stored carbon in black, and annual carbon fluxes in purple. (Illustration courtesy NASA Earth Science Enterprise)
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