>Figure 1 is a time-series graph of Global Temperature Anomalies (land and sea surface temperature) and linear trend from January 1850 to February 2010. Also listed on the graph is the calculation of the rise in global temperature (0.624 deg C) based on the linear trend over the term of the data. The year-to-year variations from El Nino and La Nina events are visible, as are the multidecadal variations caused by the Atlantic Multidecadal Oscillation. And if you study the last 30+ years of the graph closely, you can note the upward shift in global temperatures in 1976 from what is called the Great Pacific Climate Shift, and you can make out the upward steps caused by the ENSO events of 1986/87/88 and 1997/98.
The Hadley Centre’s HadCET Central England Temperature is included in the KNMI Climate Explorer webpage of Daily climate indices. Figures 2 and 3 show the daily high and low Central England Temperature from 2001 to 2009. Figure 2 presents the data in deg C, and for those who are more familiar with temperatures in deg F, I converted the data to that scale in Figure 3. The annual seasonal cycles are very apparent. Over this period, the highest temperature was 32.9 deg C (~91 deg F), and the lowest temperature was -7.3 deg C (~19 deg F), balmy by some standards. Note the red line.
THE WIDTH OF THE RED LINE EQUALS THE RISE IN GLOBAL TEMPERATURES (0.624 deg C or 1.123 deg F) FROM 1850 TO 2010 BASED ON THE LINEAR TREND IN FIGURE 1.
And yes, I got the idea for this post from an illustration used by Dr. Richard Lindzen in many of his presentations. A YouTube version of Dr. Lindzen’s November 17, 2009 lecture at Oberlin College follows.
The global temperature anomaly data is available through the KNMI Climate Explorer:
>Regarding your Figure 1, what is the value of drawing a linear trend through 160 years of data? Since it doesn't reflect any of the changes in solar activity, atmospheric aerosols, long-lived greenhouse gases etc., it's hard to see how it can tell us anything meaningful about global climate.
>Icarus: You asked, "Regarding your Figure 1, what is the value of drawing a linear trend through 160 years of data?"I used the linear trend to determine the rise in global temperature, which was then compared to the annual variation in Central England Temperature in Figures 2 and 3. The intent was to put the rise in global temperatures in perspective. That's all this simple post was about. Nothing more, nothing less.
>The increase in global average temperature is indeed small compared to the range of temperatures in the HadCET record. You could also compare it to *global* record high and record low temperatures (-89C to 58C) to make it look even smaller.
>Hi Bob,In regards to your Figure 1 time series chart where your discussion emphasizes the effects of the Great Pacific Climate Shift post 1976 to describe the increase in global temperatures. What I find interesting is that the approximately 0.4C rise in maximum temperatures post 1976 (compared to peak around 1930-40) is similar to the approximately 0.4C rise in minimum temps when comparing those minimums in the 1910-1930 period to the minimums in the 1950-1970 period. Why is that earlier period of increasing minimums not considered a reflection of some other great climatic shift also since it has a similar magnitude change over a similar 60 year period? Or does that fact ruin the nice story being pushed by the anti-AGW crowd?Dennis H.
>Hi Dennis. It’s been a while since you’ve commented on one of my posts. You wrote, "Why is that earlier period of increasing minimums not considered a reflection of some other great climatic shift also since it has a similar magnitude change over a similar 60 year period? Or does that fact ruin the nice story being pushed by the anti-AGW crowd?"What nice story is that, Dennis? I was simply making an observation about the period since 1976. Those three steps since 1976 looked obvious to me in the graph. If YOU would like to explain the rise in temperature from ~1910 to ~1945 as a natural climate shift followed by a series of natural upward step changes caused by ENSO events, please feel free to do so, Dennis.
>Bob,I was just expressing my surprise that you even mentioned things like the GPCS, since in some of our previous discussions you always seemed to not put much faith into the PDO index cycles (even recently back in your March 15 posting) and even seemed to fully disagree with Joe D'Aleo's (and even Joe Bastardi's) apparently full faith in it's cyclicallity:http://icecap.us/images/uploads/More_on_The_Great_Pacific_Climate_Shift_and_the_Relationship_of_Oceans_on_Global_Temperatures.pdfI suppose in your world the general 60-year cyclical pattern within the SST plot, somewhat related to the general trendless 60-year oscillation (cyclical) pattern of the PDO index, that the overall linear SST trendline (smoothing out of the shorter-term PDO cycles) has trended in an upward slope over the past 100+ years. I find it interesting that these general 60-year PDO index oscillations (or cycles) are generally trendless at the same time the global SST and the global CO2 concentrations have increased over that same time. Yet to you, this positively correlated upward linear trend relationship between these global SST and CO2 concentrations appears to be just a coincidence in time and you do not think they have any direct relationship with each other. But you find the GPCS has some credibility for you despite the fact that a similar 0.4C temperature increase occurred (comparing the minimums) back around the 1910-1960 period despite the fact the PDO cycles were increasingly negative: http://i44.tinypic.com/2eyb1xs.pngI have often criticized Joe Bastardi's attempts at trying to forecast the period and strength of the next PDO cycle based only on past cycles and trying to extrapolate those cycles out into the future (like he does in all his longer term forecasts) because they are so ridiculous. In that sense I agree with your point on the PDO index not being hard-wired to the 60-year cycles and Joe is really sticking his neck out there when he makes that assumption.Looking at your plot of global SST continue to positively increase over the last 29 years:http://i40.tinypic.com/4rav48.pngalong with the negative trendline of the Nino3.4 SST anomalies at the same time:http://i44.tinypic.com/24yvcrt.pngTo you it seems these negatively correlated global SST and NINO3.4 trendlines are all right and their negative linear correlations can be ignored due to some weirdly accepted naturally occurring negative relationship between them. But when confronted with the long-term, positively correlated SST's linear trendlines and the ever increasing global CO2 concentrations, they are not even considered by you to have any direct relationship with each other. That is what I find myself being highly critical of your selective logic, just like Joe Bastardi’s illogical PDO index forecasts.Dennis H.
>Dennis: You wrote, "I was just expressing my surprise that you even mentioned things like the GPCS, since in some of our previous discussions you always seemed to not put much faith into the PDO index cycles (even recently back in your March 15 posting) and even seemed to fully disagree with Joe D'Aleo's (and even Joe Bastardi's) apparently full faith in it's cyclicallity…"You’re assuming a few things, Dennis. I accept that the PDO exists, but since it portrays the pattern of SST anomalies, not SST anomalies, I don't accept that the PDO (the pattern of North Pacific SST anomalies north of 20N) impacts global temperature in and of itself. You also assume my reference to the Great Pacific Climate Shift is a reference to the PDO. It is not. The SST anomalies of the entire eastern Pacific Ocean (not just the portion measured as part of the PDO) jumped 0.2 deg C in 1976/77. That's the shift I'm referring to. It's discussed in a number of studies that make no mention of the PDO. The SST anomalies for the entire eastern Pacific cannot rise 0.2 deg C without causing global temperatures to rise at the same time:http://i41.tinypic.com/r7kgsx.pngI’ll not comment on the rest of your reply since it is based on your incorrect assumption that I was referring to the PDO.Regards
>Bob,in what way does this grouping of graphics offer a "perspective" on global warming? How does a the movement seen in the global metric over 150 years relate to nine years of daily,monthly and annual variation seen in a local record? Will you explain why combining this information is meaningful?
>Anonymous: You asked, "Bob,in what way does this grouping of graphics offer a 'perspective' on global warming?"It simply illustrates that 0.6 deg C is small by comparison to the variations in the daily high and low temperatures over the course of a year.