Africa, Drought and Global Temperature


I have seen a large number of discussions recently about droughts and how they will be getting worse with a warmer Earth.  This of course is based on the Global Climate Models (GCMs), that were created for the purpose of showing that CO2 emissions, will cause the Earth to become nearly uninhabitable, if we don’t stop CO2 emissions today.  The sad thing is how little the GCMs match up with what is known about the Earth’s climate.  In my book I touch upon Africa and how it behaved from glacial to interglacial, but I would like to expand upon that now.

The source for this information has been useful at various times and I recommend taking a longer look at it, but for now I would like to compare the stages of Africa and how the Sahara Desert has evolved, during the different global temperatures, that have existed in the past 20,000 years.  It will be obvious that Africa fairs far better when the Earth is warmer than it does when the Earth is cooler.  To put global temperatures into perspective over this time, I will show the GRIP ice core from Greenland.

 

The Inconvenient Skeptic

 

20,000 years ago the Earth was very cold in comparison to what it is today.  So what was Africa like then?

 

Africa during the last glacial. It was not wetter then, it was far drier than it is today.

 

So a much colder Earth, resulted in a much dried Africa, with far less forests and far more desert.  So as of 16,000 years ago, Africa was a far more inhospitable place than it is today and not because the Earth was warmer.  Fast forward to 9,000 years ago when the Earth had drastically warmed up.  On average the Earth was likely 1-2 degC warmer than it is today.  So how did Africa respond?

 

Africa with a warmer Earth. Far less desert and more of everything else.

 

For thousands of years while the Earth was warmer than it is today, Africa had more water and less desert.  About 7,000 years ago is when the Sahara had almost completely vanished from existence.  Consider that a warmer Earth, resulted in less desert.  That is real, actual data instead of a model, but here is what Africa looked like at the wettest it has been in the past 110,000 years.

 

Minimum time of desert, maximum expansion of the forest, grasslands and everything green.

 

It would take hundreds if not thousands of years of steady, regular rainfall to change the entire climate of a continent.  For the past 5,000 years the Earth has been cooling.  How has Africa behaved in that period of time?  The deserts have returned and they are growing.  This started long before mankind had any influence over the climate (if one assumes that we do today).  Today Africa is represented in the same method below.

 

Africa as it is today. Is it drying out? Yes, but it has been doing so for thousands of years. Only when the Earth is warmer is Africa not a desert.

 

Africa today is closer to the glacial condition than it is to the warm Earth condition.  That it continues to dry out is more evidence that the Earth is in a long-term cooling trend than one of warming.  There is no question that Africa is wetter when the Earth is warm, that the GCMs say otherwise points more to a flaw in the GCMs than it does to global warming.

One other thing to consider.  Glaciers require regular moisture to persist.  Without precipitation, glaciers will eventually evaporate away.  The glacier on Kilimanjaro is 11,700 years old.  Ask yourself, why did the glacier form then when the Earth was colder before that?  The answer is rather simple, there wasn’t sufficient moisture to maintain a glacier on Kilimanjaro during the last glacial period.  It was cold enough, but without regular moisture, sublimation will wipe out a small glacier over thousands of years.  It was only when there was sufficient moisture, that Kilimanjaro formed a glacier.  So yes, that glacier will not last, but the problem will not be temperature, but the real droughts that take place during glacial periods.

Posted in Climate by inconvenientskeptic on May 5th, 2014 at 12:28 pm.

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