Citizen Runner wrote:
fisky wrote:
My question is how do you explain the Roman Warm Period, the Medieval Warm Period, the Little Ice Age, and the subsequent warming from 1700 to roughly 1900 when CO2 levels changed very little?
In the off chance that you really care about the current understanding these events are discussed in the IPCC WG1 AR5 report in (at least) chapter 5-paleoclimate and chapter 10-attribution.
Thank you. I just reviewed IPCC AR5 Ch 5 Paleoclimate and Chapter 10 Attribution. I found it humorous that their charts clearly showed the Medieval Warm Period, but they referred to it as the "Medieval Climate Anomaly (MCA)".
Here is a quote from IPCC AR5 Ch5...
"The median of the NH temperature reconstructions (Figure 5.7) indicates mostly warm conditions from about 950 to about 1250 and colder conditions from about 1450 to about 1850; these time intervals are chosen here to represent the MCA and the LIA, respectively."
It then goes on to state that the "NH temperature of the last 30 or 50 years very likely exceeded any previous 30- or 50-year mean during the past 800 years."
That's beside the point. The MCA and the LIA are clearly shown in charts in that same chapter and clearly show significant warming and cooling without a change in CO2 levels.
I did not see an explanation for the MCA and LIA in Chapter 10. Then again, when scientists refer to the Medieval Warm Period as the "Medieval Climate Anomaly," it's obvious they can't explain it... that's the definition of anomaly. Oh, and then there's the rise from 1700 to 1850 also before the rise in CO2 levels started.
Citizen Runner, you seem like a very smart guy. Surely, you can't just ignore three major changes in global temperature in the past 2000 years as "anomalies" and then believe, without reservation, that CO2 is the driving force this time. We have four changes... MCA, LIA, 1700-1850, and 1850 to present... and you're ignoring the first three.