Discerning a trend from noisy data is one of the most basic processes in scientifc research, so even though this argument has a naive appeal to the majority of us with no statistical training, you can be sure that any scientifically trained individual trying to make a case for cooling out of this graph is not being intellectually honest. Please consider any source of this argument as very unreliable, either by being very uninformed about basic scientific processes, or very dishonest, hoping to tke advantage of less informed people.
I could apply the IDENTICAL argument you’ve made (covering the period 1850 to now) to the temperature graph of the last 1000 years (the one from the IPCC report). In this, the rise of 0.6 would simply be noise, in the same way the drop you point out can also be considered noise. You can’t bang on about how important stats and science are but then make statements like “Climate is generally defined as the weather conditions averaged over a long period, usually around 30 years.” These are not made by people with “statistical training” or “scientifically trained” individuals – where on god’s warming earth does 30 come from, except as a number which aids your argument?
Rather than create a lengthy thread so early in the life of that article, I though it was worth discussing in a brief post of its own.
In a technical sense, he has two reasonable points: first, one person’s signal is another person’s noise and second, 30 is indeed a bit of an arbitrary number when it comes to seperating weather from climate.
WRT the first point, if, say, we wanted to analyze the effect of plate tectonics on global temperature, then yes ineed pretty much everything shown in the latest 1300 yr reconstruction he refers to should be considered noise. What is noise and what is signal depends entirely on what it is you are trying to learn from your data. (And yes, plate tectonics plays a very lare role in climate change! For example, the seperation of the antarctic peninsula from the southern tip of South America seems to be the indirect instigator of the formation of the West and East Antarctic icesheets. This seperation allowed the formation of the circumpolar current that inhibits heat flow from the tropics and keeps the region cold and insulated from the current global climate change.)
But on the timescales that humanity is concerned with, (those that define climate and the abruptness of climate changes), it is senseless to look at the .8oC recent rise as just one more meaningless blip in a noisy signal. So from a practical rather than technical perspective, no it is not reasonable to use my argument on his example.
His second point about 30 years is also interesting to consider. I would say up front though, that I did not just pick “30″ out of thin air. The 30 year figure for averaging weather to define climate is a standard figure and was not choosen so I could make the point of my article, nor was it chosen by the IPCC to aid their scare-mongering drive for world domination. Because this is the accepted definition of climate, my point stands very firmly that a single point to point line of one year in length does not reveal any kind of climatic trend whatsoever. So niether of his objections to my article hold any water.
But at some point, picking 30 years was an arbitrary decision and maybe is not ideal, I don’t know.
Any takers on that question? 30 years is about half a lifetime in [developed parts of] developed nations. Maybe 60 years would have been better? Before we started shaking things up, I think people everywhere counted on some degree of consistency in weather patterns (aka climate) over not just their lifetime, but their childrens and probably even grandchildrens. Maybe 30 years is just the best number to smooth out the weather noise.
It might be interesting to hear some background on this, I don’t have the time to search for it and some things even The Google doesn’t tell you.