This miniseries is a layman’s explanation of the causes of Climate Change and its effects upon Global Warming.
Positive Feedback Loops exists extensively in many aspects of engineering, science, everyday life, and nature. It occurs when a small part of the energy of something that starts gets siphoned off into something that makes what is happening get larger and larger. An easy example to understand this better is the act of running downhills. Putting a little more effort into running downhills will make one go downhill faster and faster. Gravity serves to enhance the effort of acceleration. Too much effort placed on running downhills will result in one going out of control and even trying to slow down does not help. Eventually one stumbles and falls and continues to roll down the hill possibly resulting in serious injuries until eventually coming to a stop at the bottom. Why do I bring this up? Because Positive Feedback Loop is the mechanism or Engine that drives Runaway Climate Change
Let me explain very simplistically. Local Climate Change and Global Warming can trigger a positive feedback loop effect from a number of sources causing Global Warming to accelerate beyond just the greenhouse gases that man creates. When this happens more greenhouse gases continue to accelerate due to nature itself which may eventually be greater than man’s emissions. It is like a match igniting the fuse of a rocket which ignites the rocket fuel which produces the gas which causes the rocket to propel itself forward. There are a number of different factors that are initiated by the greenhouse warming started by man leading to runaway Global Warming. Man’s Global Warming initiates a chain reaction of other greenhouse gas emissions from nature which is the topic of this discussion.
I have comment in Part 1 that CO2 is very soluble in water accounting for its low concentrations in our atmosphere. But as the water becomes more saturated with CO2 less gets absorbed in the water and stays in the atmosphere contributing to the increase in the greenhouse gas load resulting in Global Warming. As the earth warms up so do the oceans causing million years and trillions of tons of CO2 to actually come out of the water since CO2 is less soluble in warmer water.
This is true of our lakes and other water bodies as well. As they become warmer more CO2 comes out of the water into the atmosphere. 200 years ago the CO2 in the atmosphere was about 270 ppm which is about normal. Today it exceeds 400 ppm which is the highest seen in about a million years and continues to rise. This added CO2 in our atmosphere is accentuating the Greenhouse effect causing the earth’s temperature to increase almost 3 degrees over the last 50 years. This may not seem very much but it is enough to heat the vastness of our oceans release huge stores of CO2.
But as the air and oceans gets warmer all the ice in the polar caps and glaciers around the world start to melt adding more water to our oceans and that from glaciers especially in Antarctica raising the level of ocean waters. But something else also happens. Remember in Part 1 and Part 2 I talked about CO2 being locked in the ice crystals of ice core samples? All ice on earth has CO2 trapped in the ice crystals that was once water. When the ice melts this trapped CO2 is also liberated into the atmosphere adding to the total atmospheric CO2 load. So as glaciers melt they also release CO2.
But it doesn’t stop here. As the frozen grounds (permafrost) of the northern continents start to defrost the once frozen tundras which contain ancient vegetation frozen in the ground thaw releasing trapped methane gas that has been trapped in the frozen organic material for tens of thousands of years in parts of Canada, Russia, Siberia, Northern Europe, and elsewhere, even in Antarctica from ancient forests. Remember that methane is 40 time more potent than CO2 as a greenhouse gas.
But it get even worst. As the tundras thaw the organic matter it contains continues to decay again liberating even more methane gas. So even if man were to completely cease producing CO2 today the greenhouse gas effects will continue on their own for some time. But the longer we postpone our bans on fossil fuel emissions the longer it will take to reverse the greenhouse effect. Since this much greenhouse gas emissions has never been observed in the state of earth as it stands in recent geologic times scientist do not have a good idea of how long it would take to reverse the greenhouse effect once we stop emitting it. It might take 50 years or 500 years or even 5000 years or longer. It is more likely somewhere between 50 and 500 years but they simply do not have the knowledge to predict. All they know for certain is that it is getting worst and the longer we continue to produce enormous amounts of greenhouse gases the worst thing will get and the longer it will take to reverse.
There are other new sources of anthropogenic (man-made) greenhouse gases that were also mentioned in Part 2 related to methane leaks from fracking operations used to extract natural gas which is mostly methane. Water under very high pressure is injected into shale rich areas where methane gas is stored in countless microscopic pockets. Shale is actually a mixture of sandstone and fossil fuel. Breaking up these underground layers liberates both oil and methane gas. Some areas are more rich in methane and others more rich in oil. It is all part of the same chemical process of decaying ancient vegetation millions of years old. But there is always a certain amount of methane that leaks out into our atmosphere. This all gets added to the total load of greenhouse gases. Fortunately for us UV from the sun does eventually break some of the methane gas down into non-greenhouse gas but the amount we are adding to the atmosphere is exceeding the rate of breakdown by the sun. So over time more will accumulate from natural as well as anthropogenic sources. This is all not very good news for trying to reverse Global Warming.
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