Post by Dr. Ryan N. Maue
December global surface temperatures cratered after the Cancun climate confab, which ended a string of above-average months. However, until the government temperature keepers put out their 2010 autopsy and bubble plot with the appropriate fanfare and press release, I am going to use the tools at my disposal to come up with a reasonable estimate of the recent global temperature.
From operational and reanalysis numerical weather prediction best-estimates of the atmosphere-ocean state, the global mean temperature for December 2010 [image link] was actually below the previous 30-year mean pushing 2010 down the list of the hottest ever. Europe, North America, and Australia saw much below average December temperatures, while the Arctic saw much above average temperatures (but that’s relative, it’s still really cold)
You must look at the weather — weather is part of the climate — and understand the high-frequency redistribution of heat, moisture, and momentum on the order of days and weeks. I will show you now why the weather matters.
Temperature Fluctuates Wildly on Short Time Scales: Weather
Here is a daily trace of the JRA-25 reanalysis near-surface temperature anomalies for 2009 and 2010 based upon a climatology of 1980-2009, a 30-year chunk of climate. Reanalysis datasets do have their issues, but also advantages, which are beyond the scope of this simple show-and-tell. There’s nothing sketchy going on here; no hiding of any declines; just showing you the data!
The blue-line is the zero-line corresponding to the 30-year mean. Blow it up and you see, what people can observe is the weather, and weather is not climate — except when it is. This plot shows you how temperature changes due to the global weather flow-regimes, which are modulated by all of the natural climate actors like El Nino, La Nina, the NAO, AO, AAO, etc. The daily temperature time series is extremely noisy and fluctuates wildly, but there appears to be a rhythm to the madness. I’ll leave that as homework exercise to explain the ups-and-downs (hint it’s weather). I find it rather discouraging that the entire time series I plot up is boiled down to one annual number, and an AGW signal is somehow sucked out — with a blizzard attributed to it no less! Even the IPCC AR4 models say we have many decades to go before seeing such visible changes.
Since we are using the previous 30-years as the baseline, the anomalies have course decreased in magnitude in the recent 1980-2009 period. The usage of 1961-1990 or 1971-2000 will provide the same qualitative picture, but there will be some important differences (future post). The Earth didn’t warm uniformly between the separate “climate normals”, and it isn’t expected to. That’s part of the point of my message here.
Temperature Fluctuates Spatially: Weather
Spatially, you can see the action of the temperature anomalies from the plot at the beginning of the post:
This is a great way to visualize all of that global warming going on. The image at the top is the most recent 14-day average ending December 30, 2010 showing the extreme Arctic warmth of +15 to +20C, and of course the northern Eurasian chill. If you mouse over the plot, you can watch the course of the past year go by. The development of the La Nina in the Pacific is apparent as the summer wanes. You can find the Russian Heat Wave pretty easily in July, even though 2010 ended up pretty much average there. If you desire, you can change the URL in your browser to see similar animations for the past 30-years: 1979 … 1989 … 1999 … 2009. Have fun with the weekly animations of temperature — all of the major cold blasts are in there for the USA…
What’s the Temperature Right Now?
But, what is the actual temperature: if it is 15 degrees C above normal in the Arctic, what does that mean: well, here is a global temperature analysis and 7-day forecast from my Florida State Weather Map page. Also, below this image, is the departure from normal, so you can see in real-time just how hot the planet is — and watch as 2011 starts off as just an average year. You’ll hear a lot about the historically warm Arctic, but who cares at this point, no one lives there and it is still plenty cold. Is that a global warming signal in winter up there? I doubt it, how about storm tracks, blocks, the NAO, and some natural climate variability manifested in the weather?
We are talking hundredths here? Really?
It’s a foregone conclusion that the official government data from whatever nation or agency will show that 2010 was the hottest year ever. It just has to be that way — please don’t look at that snow burying NYC or the bone-chilling historical cold throughout the UK and Europe, that’s just the weather. Instead, look at the articulate press releases with the bubble-plots from NOAA/NASA to see the real story of 2010, the hottest year ever by a few hundredths of a degree C. Yes, we are talking about hundredths and tenths of a degree during the past 10 to 30 years– that’s all. The Earth’s temperature varies a lot, from hour to hour, day to day, season to season, year to year for a bunch of reasons of which the sun is order 1, but even through all of that, you must know that the global temperature has changed only on the order of a 1-3 percent during the past 30-years. And, it isn’t a spatially homogeneous change, either. Not even close. AGW is built upon the premise of a slow, very slow upward trend that will eventually accelerate. But, that’s a long ways off — today, we are talking about hundredths of a degree C. How many trillions of dollars is that worth to you?