Update on Arctic Temperature – RSS July Anomaly
Posted by The Diatribe Guy on September 4, 2009
Since the Arctic always seems to be the “hot” discussion point in the discussion of climate change and global warming (does it seem unusual to anyone else that a discussion of a supposed global phenomenon almost always seems to come back to a discussion of melting ice in the Arctic?) I thought I’d provide an update on the Arctic charts. Since I’ve already mentioned the ice, let’s see what that’s up to (from the IJIS data – link on the right):
I posted this on a comment on The Air Vent but I’ll repeat it here:
Anyway, in looking at the IJIS chart (not only above, but the current one) it seems pretty much as expected. I’m going to reference a post I made in early June: http://digitaldiatribes.wordpress.com/2009/06/04/quick-hit-post-on-the-arctic-ice/
Where I said this: “As of today, June 4, it is below the 2003 level, but holding in second position. As an aside, I wouldn’t at all be surprised to see this tail off quite a bit and dip below most of the years again. Looking at 2008 this happened, but not to the extent that it melted in 2007. It can reasonably be expected that the ice just won’t jump by leaps and bounds at maximum melt, while still in an increasing mode. So, 2009 may well dip below normal before it’s said and done, but my own guess is that it will still end up higher than 2008, thus continuing the upward trend.”
Unless we get some serious meltage going on soon, it looks like I’ll be right. Am I proud? Not really. It’s pretty much common sense along with a rudimentary understanding of Physics, energy requirements, and heat transfer. One doesn’t need to be an expert to look at the temperature trends along with 2007 ice levels and develop the idea that there will be a likely slow positive accumulation of ice over time.
So, what do I mean by these temperature trends? I mean, it’s warming in the Arctic, right?
Let’s take a look. All data is directly from the RSS data link that is located on the right, under resources. I suppose if you believe it to be bogus, you can take it up with them…
July Data Point
The anomaly in July was 0.2380 (in degrees Celsius, heretofore referenced as 23.80 in 0.01 degree Celsius units).
Rank and Average: Of the 367 anomalies, it ranks 179th highest – almost at the 50% median. If you’re wondering about averages, the anomalies don’t average out at zero, as they probably should. This is just a convention, but can cause some confusion, because we naturally think of the zero line as the average anomaly. In fact, the average anomaly in the data is 20.46. So, the July anomaly is basically at both the median and the average.
The 2009 July anomaly ranks 15th of 31 July anomalies in the data. So, all the way around, this was just a boring, average, temperature reading.
Movement:The June anomaly was also right there, at 25.00. So, the July anomaly was only a slight decrease of 1.20 units. The decrease from July 2008 is more pronounced: -17.80 units.
Streak: July showed the third consecutive anomaly that was lower than previous year. Of the last 23 anomalies, 17 of them are lower than the previous year.
12-month Average: The 12-month average anomaly is 44.4. This has been coming down fairly consistently for a while. This is the lowest 12-monthly average since the period ending January 2005.
The overall trend line since inception of the data in 1979 is definitely positive. The recent decline is not enough to offset the long-term warming that has occurred in the region. From 1997 to 2006, you can see the steady increase in the temperature anomaly, which was a sure contributor to continued lower ice extent over that period. The second-highest singular peak anomaly occurred in 2007, at a value of over 2.00 (first place goes to a value in 1981 that was over 2.50). The current trend line over the 30+ years represents 3.20 degrees Celsius warming per Century.
So, the longest term to evaluate that we have is positive, but the current period of time has stagnated (if not reversed). We can draw a line back to April 2001 for which we have a slightly negative trend line. This could mean all sorts of things, from stagnation within a continued warming trend, stagnation moving forward, or a reversal of the trend, where the line is simply being fitted around the peak. (I’ve used the analogy of climbing a mountain. As you walk up, your “trend line” for increasing elevation by time is increasing. When you reach the peak and then start moving down the other side, your trend line actually continues to increase for a time until you meet it again. But it will take some time for it to finally flatten to zero… in fact, if you measure the trend from your starting point, it will only show zero once you’re at the bottom. So even though you spent as much time moving down as you did moving up, you always showed a positive trend line. This is one reason why it is helpful to view how the trend line is shifting over rolling periods.
Anyway, I’m not saying that this is the case here, but I’m not saying it isn’t. Those who suggest it must be one and can’t be the other are either relying on other information to make that statement, or are simply being dishonest. But here’s the statement of fact: For the temperature anomalies produced over the last eight and a half years, the trend line in the Arctic is negative.
I like to show a recent peak or trough trend line to show where we were versus where we are now. Almost six years ago, the short-term trend line (5 years) peaked at a very high slope value of 1.4039, or an alarming 16.85 degrees per Century rate of warming. It’s no surprise that we saw an increase in the amount of ice meltage (is that a word?) earlier in this decade, peaking in 2007. This was also the peak season in advertisements and such showing floating polar bears, and this is when the Arctic became the poster child for global warming.
Clearly, had this rate continued, the entire cap would have melted on schedule. And the issue here isn’t that there wasn’t indeed spike in warming. The issue is that those who saw this five-year trend and prognosticated doom were breaking their own rules – a five year period is wrought with fluctuation. It’s unreasonable to use that to extrapolate to long-term projections.
So, what happened since that peak? The chart above shows us that, since 2003, we have come down from that peak 5-year slope value to a current clope value of -0.7093. That’s a cooling rate of 8.51 degrees per Century. Of course, the people today that are strong AGW proponents will be the first to tell you that the 5-year trend line can’t be used to extrapolate out such things. And they’re right. A pity we can’t get uniform consistency on this issue.
So, how do these 5-year slopes track over time? Until recently, they were consistently positive to one level or another for about 8 years. Prior to the little dip before that, there was another period of a positive trend line for about 5 years, and while not as long, this one showed a 5-year trend at nearly 2! This chart certainly shows enough consistency in the positive trend lines to indicate that the temperatures have been rising for a period of time. There are two points to make on this, though: (1) I reiterate that the actual average anomaly is over 0.2, no zero. That shift would give the chart a slightly different flavor, though it still leads to similar conclusions; (2) We’re looking at a span of 30 years. It’s silly to draw too many conclusions. As we see, the right side of the graph has trrended down consistently now for six years, and the current 5-year slope is the lowest we’ve seen since the period ending March 1994. In the ice extent chart at the top of the post, we see the early appearance of a rebound in ice, with corresponds with these temperature trends. Do we really need to panic?
So, we’ve seen temperatures decline in recent years from the high levels they achieved. However, since that’s recent enough, and since we haven’t quite made it to the “bottom of the mountain” we will still continue to see positive trend lines on the longer time frames. Maybe we won’t reach the bottom, and the next mountain starts above the level of the first one. Time will tell. But the current 10-year trend line is at a rate of 2.40 degrees Celsius warming per Century. This trend line is currently the lowest value it’s been since the period ending August 1995. That speaks both to the extent of recent cooling, as well as to the persistency of increasing values over that time prior to the recent cooling period.
We can see the 10-year slop values over time here, and it will now be interesting to see if the lower slopes continue downward in similar fashion to the speed with which they increased in the early 1990s.
The most recent 180-month trend line is showing a rate of warming of 3.27 degrees Celsius. Despite the level, the slope value is also trending down, and is at its lowest point since the period ending July 1998.
The 20-year peak value occurred in January 2007, just preceding the minimum ice extent occurring the subsequent summer. While the short-term trend was turning negative even at that time, the anomalies themselves were still high enough to increase the trend line and induce additional melting, even if starting to come down (If your oven is 450 degrees and you cool it to 400 degrees, it may have cooled down, but it can still bake a pizza… but if you keep cooling it off, at some point it will stop baking.)
The 300-month slopes are shown here to demonstrate that it takes a while for these longer-term slopes to reflect short-term changes. We know the 5-year slope is quite negative at the moment, and yet the 300-month slopes have only fallen a little bit, and aren’t far off from where they’ve been for the last 2-3 years, and above the periods before that. One reason why people do like these longer-term periods is the stability they have against random fluctuations. This is the positive aspect. The downside is that the longer your term, the slower it is to react to an actual change in the trend. So are the current short-term results a random fluctuation, or the actual reversal of a trend? That’s the rub, isn’t it? The only way to really know, despite what the fancy modelers say (who are usually wrong) is to see what happens. But.. but… we need to act NOW!!!
Yeah… call me a nut, but I find that a dumb argument. Suppose you have an illness, as of yet diagnosed. There are certain things you can do that are beneficial to you regardless of your diagnosis: eat right, get enough rest, drink fluids, etc. But if a doctor says “but we have to do something!” and gives you a medication and put you through expensive and painful procedures that might help you, but on the other hand, could do more harm than good, then why would you do it? Just because we have to do something? No, you only do those things that you know are beneficial to you, and you wait for a firm diagnosis before engaging in expensive procedures that will be miserable to you that might just kill you anyway if the diagnosis is wrong.
And this is how I view environmentalism and the planet. I am all for restricting pollutants that we know are bad for us and for the surrounding ecosystems. I am all for encouraging a wise use of our resources through education and incentives. What I don’t want to do is implement carbon taxes and spend billions of dollars on a misdiagnosis. Maybe that’s just me.
Finally, if we take the worst-case 30-year trend line (though keep in mind there are only a handful of data points so far) we see a warming trend of 3.37 degrees per Century. I suppose one can see this as an ominous harbinger of things to come for the rest of the globe that, for whatever reason, has started in the Arctic and will be working its way down. Or, someone can look at it as a regional phenomenon that is simply unstustainable in the context of the rest of the globe, which should at some point act to moderate and/or counteract it. I personally take the second view, though I admit to this being more opinion than science.
To all in the U.S., enjoy your Labor Day weekend! I am pretty excited to actually see beautiful weather and temps forecast for the entirety of the weekend. Lawnmowing, fishing, fairs, and general entertainment are on the docket for this individual.