Friday, 8 February 2013

Climate Change and Geological History


Does the term "climate change" make sense? It makes about as much sense as the term "wet water." In other words, "climate change" is redundant. So when "climate change" is used, what does it really mean? It really means global warming caused by human activities. Of course climate changes. It always has and it always will on planet earth. As to how much impact human activity has upon changing the global climate is concerned, is another matter altogether.
 
 
Historical Context
 
As far as geological history is concerned we are currently living in an Ice Age. No, the Ice Age did not end, we are still living in it. The current Ice Age we are living in has been going on for the last 2.5 million years. The presence of the ice sheets on Antarctica and Greenland establish the fact that we are still living in the Ice Age.

We are, however, living within an Interglacial episode within an Ice Age. This current Interglacial episode started around 12,000 year ago. The chart below expresses this concept rather well:



This chart spans 415,000 years, and we are in that little orange peak at the far right. There were just 6 Interglacial episodes in the last 415,000 years, and they are far shorter than the periods of Glaciation which last tens of thousands of years. The last Glaciation episode lasted for 100,000 years. During that time 30% of the earth's land surface was under ice sheets equivalent to the thickness found on Antarctica, which ice sheet is about 2 miles high at its centre.

During this current Ice Age, more than 85% of the 2.5 million years, the earth has been consumed within periods of Glaciation which made it most inhospitable and caused the extinction of many species of animals. The Interglacial episodes have been warming periods conducive to allowing life to thrive.

Are we headed for another period of Glaciation? Looking at this chart, and knowing that we are still within this Ice Age, the answer would be "Yes." That is some bad news if you are closely attached to human civilization, because an episode of Glaciation would more than likely destroy it. Also, there is strong evidence to support the scenario that when glaciation starts, it is not a slow process but relatively quick - over a time-frame of just a few decades for huge glaciers to start forming all over the place and making life very unpleasant.


Our Interglacial Episode

Human civilization started with this current Interglacial episode we are living in. Scientists call this episode the Holocene Epoch, if we want to get technical about it. So even though life has thrived during these last 12,000 years, there have also been warming and cooling periods within it. At the present time, we have been within a warming period since around AD 1850. The chart below expresses this current Interglacial episode.

 

We are currently living in that little red area to the far right. Please note all the other red areas on this chart over the last 9,000 years. These red areas reflect warming trends within this Interglacial within which we are living. Some of these warm periods were a lot warmer than our current time period. Also note the pattern for the last 4,000 years - each warming or cooling trend lasts for about 500 years, give or take a century. This could perhaps mean that this warming trend we are now in will last another 300 years or so.

But wait! What about all our human industrial pollution that is causing global warming? Isn't it humans who are making the world warmer?


Taking a Step Back

In order to answer the previous questions, observe the two charts above and ask yourself this question: Where was all this industrial pollution warming the climate during all the other warming periods within our Interglacial episode, and where was it in all the other Interglacial episodes for the last 415,000 years? The answer is plainly simple - it wasn't there. The climate does not need human industrial pollution in order to warm. Mother Nature does it fine all by Herself.

However, my answer may not be satisfying to many since the warming trend we are currently in could be influenced by human activities. You are quite correct, if this was your response. After all, the media has been telling us for decades that the climate is warming because of human activity, and even the UN established the IPCC (Intergovernmental Panel on Climate Change) to explore climate change and global warming, based upon the assumption that mankind is affecting the climate. The United Nations could not be wrong, surely, on such an important issue, could it?

The point this particular blog article wanted to establish was that for the climate to warm, Mother Nature can do this all by Herself. What it also wanted to establish, was that the world was due for a warming trend by AD 1850, since the last cooling period had run its course of about 500 years. We are now in a warming trend, and that is the effect. What we need to establish is the cause, and that is for a future blog article.

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