The MWP Is Important, But Maybe Not What You Think For

In the raging debate about CACC (Catastrophic Anthropogenic Climate Change) formerly known as CAGW (Catastrophic Anthropogenic Global Warming) you keep hearing about something called the Medieval Warm Period (MWP). Now one side of the debate says it’s important and the other says it isn’t and IMHO both sides are right and both are wrong.

Now that I got you confused because you are scratching your head and saying “They can’t be both right and wrong”, I’ll explain how that is a true statement.

Skeptics say the MWP is important. The reason they typically say it’s important is that it shows the late 20^th century warming is not unprecedented. The reason they are wrong is the fact you don’t need the MWP to prove that, the earlier Roman, and Holocene Optimum warm periods show that the 20^th century warming is not unprecedented. Also the previous interglacial’s show that as well, so you don’t need the MWP for that which is where the Alarmists get it right.

Now where the Alarmists are wrong and the Skeptics are right in that the MWP is important is not strictly for how high the temperatures were during that time. It has been shown in numerous studies that there was a MWP and even Dr. Keith Briffa of the CRU believes there is one, so what makes it important is not how high the temps rose but that they did rise and the relationship between Temperature and CO2. If you remember back to the famous graph in Al Gore’s fiction film “An Inconvenient Truth” where you saw a graph where one followed the other one of the things he got wrong about them is that he had them backwards. In the film he showed temperature rising, after an increase in CO2 when in fact the opposite occurs. It should be well known by now that an increase in Temperature gets a corresponding increase in CO2 800 to 1000 years later. So if the temperatures did rise during the MWP then 800 to 1000 years later there should have been a corresponding natural rise in the CO2 level in the atmosphere. So first things first when did the MWP occur?

Well according to NOAA the MWP occurred between the 9^th and 13^th centuries:

Medieval Warm Period – 9th to 13th Centuries Norse seafaring and colonization around the North Atlantic at the end of the 9th century indicated that regional North Atlantic climate was warmer during medieval times than during the cooler “Little Ice Age” of the 15th – 19th centuries. As paleoclimatic records have become more numerous, it has become apparent that “Medieval Warm Period” or “Medieval Optimum” temperatures were warmer over the Northern Hemisphere than during the subsequent “Little Ice Age”, and also comparable to temperatures during the early 20th century. The regional patterns and the magnitude of this warmth remain an area of active research because the data become sparse going back in time prior to the last four centuries. http://www.ncdc.noaa.gov/paleo/globalwarming/medieval.html So that means that the MWP occurred between the years 801 AD and 1300 AD. It also states that it started towards the end of the 9th century so that definitely means it’s between 850 AD and 900 AD. Now take the time lag for the corresponding rise in CO2 and what years do you get: 1650 to 1900 AD before you see a rise at the earliest. These are rough estimates from the range of the MWP. So lets take a look at what the US Government says the historic CO2 levels have been during that time period: This graph was taken from a US government report here: http://clinton4.nara.gov/Initiatives/Climate/greenhouse.html

Now look at that according to this the CO2 started rising around the year 1860 AD, hey what do you know that corresponds to the lag you get from the MWP (860 AD to 1060 AD). So if you go from there the rise of CO2 that would naturally occur from the natural rise in temps in the MWP could end between: 2001 AD and 2300 AD. To get this subtract the earliest end point year with the latests start point year 1201 – 1060 = 141 then add in the 1860 start point for the CO2 = 2001. Now repeat with subtracting the earliest start point year from the latest end point, 1300 – 860 = 440 then add in the 1860 start point for the CO2 = 2300.

So what does that mean? It means this:

Yes Humans are pumping out CO2, however unlike what the Alarmists want you to believe the rise in CO2 levels is not all due to man, part of it is the natural rise you get from the MWP. How much of a rise I haven’t myself calculated or seen somewhere else calculated, but you will get a natural rise and it might even be large enough that we could continue emitting CO2 and see CO2 levels drop in the next coming years. Maybe that is why the UN and the Alarmists wanted the Copenhagen accords signed so badly, if the CO2 levels start dropping without some over arching UN made, global governance mandate for man made emissions reduction and the levels drop on their own there goes the whole CAGW theory out the window. So if the warming during the 20^th century was natural and not caused by man made CO2, you could see temps still rising with a reduction of the CO2 levels with out Human emission reductions. That is why the MWP is important it could explain the majority of the CO2 rise during the 20^th century without a correlation in 20^th century temperature rise.

So until someone does a study on how much of a bump the MWP could cause in CO2, what I just posted might come to pass. Of course I might have missed a study on this that says it was small and won’t play any major role and if any one knows of one post it in a comment so I can read it.