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 getting 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 move you down hills. But when you try to add force by going faster you start accelerating much faster than just the effort you put in.. 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, you 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 the 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 Natural sources causing Global Warming to accelerate beyond just the greenhouse gases that man creates. Remember that natural sources of greenhouse gases are found in our seas, ice and glaciers, and tundras. When this happens the planet becomes warmer causing more greenhouse gases to be released and further warm the planet causing even more greenhouse gases to be released from nature itself which may eventually be greater than man’s emissions. This is called the Tipping Point whereby nature takes control of runaway Climate Change and man plays a backseat. At this point man will not be able to reverse Climate Change with our current knowledge which could eventually end life as we know on planet Earth. This won’t happen suddenly but over perhaps several hundred years. But it could be devastating all the way up to the end when water boils off the surface of Earth.
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 is no stopping the rockets once the fuse has lit the main rocket (tipping point). There are a number of different factors that are initiated by the greenhouse warming started by man leading to runaway Climate Change. Man initiates a chain reaction of other greenhouse gas emissions from nature which is the topic of this discussion.
I have commented in Part 1 that CO2 is fairly soluble in water in part accounting for its low concentrations in our atmosphere. But as the water becomes more concentrated less CO2 is absorbed in the water and stays in the atmosphere contributing to the increase in the greenhouse gas load resulting in warming the earth. As the earth warms up so do the oceans causing million years and trillions of tons of CO2 to actually come up from the bottom and out of the water since CO2 is less soluble in warmer waters.
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 almost 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 1.5 degrees C 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 become warmer all the ice on the glaciers around the world start to melt adding more water to our oceans and that especially from Antarctica, raising the level of ocean waters flooding all costal landmasses. 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 end 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 over eons start w thaw releasing trapped methane gas that has been trapped in the frozen organic material for tens or hundreds of thousands of years in parts of North Canada, Alaska, Russia, Siberia, Northern Europe, and elsewhere, especially in Antarctica from ancient forests. Remember that methane is 30 times more potent than CO2 as a greenhouse gas.
But it gets even worst. As the tundras thaw the organic matter it contains continues to decay 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 until the tipping point is reached and runaway Climate Change takes over. Since this much greenhouse gas emission has never been observed at this stage on earth as we know scientist do not have a good idea of how long it would take to reverse the greenhouse effect once we stop emitting it. But this is what current models show might happen. The Tipping Point might have passed or may take 30 years to happen but they fear we might be very close and this makes them extremely nervous and even scared. They simply do not have the knowledge to predict this accurately. All they know for certain is that things are getting worse and the longer we continue to produce enormous amounts of greenhouse gases the worst pushing us closer to the Tipping Point.
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 largely methane gas. 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 oil. Breaking up these underground layers liberates both oil and methane gas. Some areas are richer 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 rays 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 Climate Change. Offshore drilling of oil also releases some methane gas.
Links to this Miniseries:-
- Climate Change: Part 1 – The Fundamentals
- Climate Change: Part 2 – Greenhouse Gases
- Climate Change: Part 3 – Runaway Climate Change
- Climate Change: Part 4 – How Storms & Hurricanes Form