Seems our faux Lord has once again been caught lying about the data. Monckton Chronicles Part IV? Medieval Warm Period? Now we will turn the clock back to a time that is often referred to as the medieval optimum, or the Medieval Warm Period. It is well known that approximately 1000 years ago, there was a warm period which spanned at least part of the northern hemisphere. This warm period is often used by climate deniers such as Christopher Monckton to incorrectly assert that todays warmth is not unusual. Since there were no thermometers around at the time, researchers have to use what are often called proxies to measure temperatures. Proxies are indirect measurements, they are never as accurate as real thermometer data, however, they at least give us an idea about past climate. A graph showing different researchers temperature estimations is shown in Figure 1. The measurements extend back to 800AD. Modern time is on the right side of the graph. Each line represents a different researchers reconstruction. What you can see is that there is a lot of uncertainty in the proxies. You will also notice that as we approach modern times, the amount of uncertainty decreases significantly. What you should also notice is that the curves generally agree that there was a warm period from about 950-1150AD. This period is the so-called Medieval Warm Period.