UPDATED 11 a.m. EST with GFS model forecast.

There is no question the snowstorm just entering New England will be a big one, and that local snowfall totals will set daily records in many locations.

But are we looking at an all-time storm snowfall record event?

There have been only a couple of New York City storm snowfalls which have exceeded 2 feet (24 inches). This one looks like it might exceed that, but with every 6-hourly weather forecast model cycle the story has changed from an epic storm, to a noteworthy one, then back to epic.

For example, last night’s GFS model run looked like maybe a foot or so of snow for NYC. A major inconvenience, but not an all-time record-setter.

Then, this morning’s higher-resolution NAM model is giving Long Island as much as 3 feet of snow by Tuesday evening, and at least 2 feet in NYC (first two graphics courtesy of Weatherbell.com):

Then, the GFS model came out with only 6-12 inches for the NYC area.

This indecision by the computer models has been going on for the last few days. All we know for sure is that the most recent forecast is usually the most accurate, but we now have wildly conflicting forecasts from the two most recent model runs. The GFS model has the heaviest snow total — approaching 2 feet — over southeast Massachusetts. Much of the rest of coastal New England is forecast to get about 1 foot of snow:

Which model is usually better? For this kind of event, the GFS model (less snow) is usually (but not always) more accurate.

Finally, we have the NWS multi-model product (using over 50 different models and model ensemble members…even using ECMWF) which comes up with sort of a best-estimate of the total snowfall (click for full-size):

Note that it is calling for 15-18 inches for the NYC-Long Island area, increasing to 2 feet around Boston.

The Long Island snowfall record was smashed on Dec. 20, 2009 when just over 2 feet of snow piled up.

In New York City, many snowstorms have produced 15 inch snowfalls, but only a couple have produced 2-foot snowfalls. In Feb. 2006, the all-time record was set at just under 27 inches. In 2nd place, December 26-27, 1947 saw a 26 inch snowfall.

High winds will make the current storm worse than normal for a snowstorm, with winds easily gusting over 30 mph in NYC, but Long Island and portions of coastal New England can expect 50+ mph gusts. In this kind of weather situation, it is also likely that lightning and thunder will occur in some locations. Most of the snow will fall tonight and early tomorrow.

What I’m dreading is for the next week reporters are going to be asking me about the role of global warming in all of this. Well, if the weather conditions were only 5 deg. or so warmer, we would be talking about a wind and rain non-event. But with colder air, it will be a major snowstorm.

Now, if you really believe global warming causes colder conditions, I have a snow-covered bridge in Brooklyn I’d like to sell you.

With the media now in full-panic mode, over three thousands flights cancelled, and Connecticut banning all auto travel after 9 p.m., it will be interesting to see how all this plays out. Say, with tomorrow’s photos of the stranded cars:

Tomorrow night an asteroid the size of a small mountain will pass about 3 Moon distances from the Earth, and will be in perfect position for binocular viewing in the U.S. Details and a tracking chart are available at Sky and Telescope. I also use their interactive sky chart to find the locations of constellations, clusters, planets, etc., for specific nights and my location.

Asteroid 2004 BL86 will be moving at about 2.5 deg. per hour generally northward and pass right next to the Beehive Cluster (M44) between 11 p.m. and midnight CST. It is estimated to be over 500 meters in diameter, which is like 5 football fields long (and high and wide).

From what I’ve been able to find on the energy equivalent if one of these bad boys hit the Earth, this one would easily wipe out the entire New York City metro area. (The resulting climate impact would likely be cooling for years, but I don’t believe in the nuclear winter scenarios where most life is wiped out — dust settles out of the atmosphere relatively fast).

For those of us in the central time zone, the asteroid should be visible in binoculars with a fairly dark sky, brightest around 11 p.m. till midnight (when it will be fully illuminated by the sun on the other side of the Earth), and will be almost directly overhead. If the clouds move out of N. Alabama in time, I’ll be doing time lapse photography and will post a video if weather permits. I’ll be using a 200 mm f/2.8 lens at f/4.0, 30 sec exposures, ~ISO 2000, and star tracking with an AstroTrac on my tripod. Those settings provided this view of the Pleaides (about the same size as the Beehive Cluster) last night from my backyard:

No, I’m not talking about how the climate system has helped dummies make money off it.

I’m taking the occasion of continued pestering by our Aussie friend Doug Cotton, and questions I still get about his views, to go over the basics.

The atmosphere is complex enough that, from time-to-time, I try to explain the average operation of the climate system in as simple terms as I can muster. It’s actually quite difficult to simplify it.

I’m going to make some broad generalizations here, and my statements should be accurate to at least the 90% level. Maybe even 97% 😉 What follows is for the “global average” climate system.

The source of energy for the climate system is the sun, primarily in the form of visible sunlight.

About 30% of the sunlight which reaches the Earth is reflected back to space, and most of the rest is absorbed by the land surface and the upper 10 meters or so of the ocean.

The absorbed sunlight would cause the temperature of the land, ocean, and atmosphere to eventually increase without bound unless there were ways to lose the accumulated energy. The most important energy loss mechanism for the climate system as a whole is infrared (IR) radiation (yes, Doug, IR is also “electromagnetic radiation”, as is visible sunlight), which is how the Earth as a whole maintains energy balance and an approximate constant temperature: the total sunlight absorbed by the Earth equals the total IR energy emitted out to space by the Earth. Here “Earth” means the earth-atmosphere system.

Since the rate at which the Earth emits IR radiation goes up as the 4th power of the absolute temperature (measured in Kelvins), this provides the ultimate stabilizing mechanism for the temperature of the climate system. (There can be no “runaway greenhouse effect”. Even Venus has a stable temperature.) In crude terms, the sun warms the climate system up until it emits IR energy to space at the same rate it absorbs solar energy.

Anything that changes the balance between energy input and energy output of the Earth has the potential to change its temperature. This “energy-balance-determines-temperature” concept is basic physics, and is fundamental to the calculation of the temperature (or change in temperature) of anything, and is accounted for in the design of most energy-consuming devices humans have invented.

So, if clouds change, the temperature can change. Or, if the amount of IR-emitting and IR-absorbing gases in the atmosphere (primarily water vapor and CO2) change, the temperature can change. Anything that changes the rates of energy gain or energy loss can change global temperatures.

Now, a good portion of the solar energy that warms the surface causes convective air currents, which transport heat upward (not downward, as Doug claims), which then warms the troposphere. Evaporation of surface water is a major portion of this process: evaporated water at the surface absorbs the “latent heat of evaporation”, which is then released to the atmosphere when the water condenses into clouds and precipitation. This is what drives most clouds, all precipitation systems, thunderstorms, hurricanes, etc. They all convectively transfer heat from the surface to the atmosphere (not from the atmosphere to the surface)

Importantly, with this convective energy input into the atmosphere (and some direct sunlight absorption by the atmosphere), the atmosphere (specifically, the middle and upper troposphere) must have some way of losing this energy, or its temperature would also increase without bound. This cooling mechanism is accomplished by IR emission to outer space by those “greenhouse gases” in the atmosphere I mentioned earlier.

But those gases don’t just emit IR radiation upward to outer space, they also emit downward, reducing the net IR cooling rate of the lower atmosphere and surface. (Sideways emission and absorption are almost exactly the same locally, and are the same in the global average, so are ignored). The net result of all of this up- and down-welling IR radiation is that greenhouse gases make the upper atmosphere cooler, and the lower atmosphere warmer, than they would otherwise be without those greenhouse gases. This was first demonstrated by Manabe and Strickler 50 years ago (a nice summary of their model is here).

I have often used the analogy of a blanket over your warm body. A blanket keeps the warm side warmer, and the cool side cooler, than if the blanket was not there. Yes, I know, a blanket primarily works by conduction, but in terms of energy transfer in general, the concept of the atmosphere as a “radiative blanket” is the same. (Real radiative blankets really are used in the design of some instruments flying on satellites, to help keep them from getting too cold when they are not in the sunlight.)

Not to belabor the point, but this is really important, and some people are creating confusion with their misinformation. The rate of energy input alone does not determine the temperature of an object, (Doug). If you can insulate the object sufficiently, you can elevate its temperature arbitrarily high with relatively little energy input. All you have to do is prevent it from losing energy as fast. Temperature is determined by rates of energy gain and energy loss.

Due to greenhouse gases, the rate at which a layer of the atmosphere absorbs IR is relatively independent of its temperature; but the rate at which it loses IR is very dependent on temperature. Thus, layers of the atmosphere are, in general, not emitting IR at the same rate they are absorbing IR.

If not for the emission and absorption of thermal IR by different layers of the atmosphere, we would not have the IR temperature sounders on satellites that provide atmospheric temperature structure data on a global basis that have greatly improved daily weather forecasting. Nor would John Christy and I be able to monitor the temperature of different layers of the atmosphere due to the (extremely weak) thermal microwave emission by oxygen in the atmosphere.

In fact, without the greenhouse effect cooling the upper troposphere and warming the lower troposphere, the atmosphere would not become convectively unstable, and weather as we know it would cease. Sunlight and IR radiation transfers, by themselves, “try” to make the troposphere very unstable to convection, and it is the resulting convective overturning that makes the tropospheric lapse rate somewhere between the dry adiabatic value (9.8 deg C/km) and moist adiabatic (~6 to ~9 deg. C/km).

This is key: without IR absorption and emission by the atmosphere, surface heating by the sun would eventually warm the atmosphere to the same temperature as the surface, and such an “isothermal” atmosphere cannot support convection. The observed tropospheric temperature profile (warm below and cool above) is mostly the result of convective overturning, responding to constant destabilization by surface heating combined with middle- and upper-tropospheric IR cooling to outer space.

Yes, gravity is important to the whole process – but not in the simplistic way a few people think. Gravity is indeed a necessary part of determining what the dry convective lapse rate is, but that lapse rate only occurs in response to convective overturning, which in turn requires the greenhouse effect to destabilize the atmosphere in the first place.

The equations representing all of these physics can be put into a time-dependent one-dimensional model (we and many others have done this) that computes temperature changes at hundreds of different levels throughout the atmosphere. You can initialize the model at absolute zero temperature, or 1,000 Kelvin, it doesn’t matter…the resulting equilibrium temperature profile the model settles down to when it is run looks almost identical to the observed temperature profile.

Until someone does the same time-dependent modeling with their “alternative” physics (which are supported by laboratory measurements, as are [for example] the IR absorption properties of various gases), their hand-waving about gravity explaining lower atmospheric temperatures should be taken by non-specialists with a huge grain of salt. Specialists already ignore it entirely.

I realize the above explanation is too technical for some. But the atmosphere is an amazingly complex place, and atmospheric radiative transfer isn’t easy to grasp with intuition alone. I’ve been down the road of questioning the standard explanation of the “greenhouse effect”, and convinced myself it is, indeed, real.

But whether our ~1% enhancement of the natural greenhouse effect after 100 years of burning fossil fuels will cause enough warming to worry about is another matter entirely.

After almost two months of mostly balmy winter weather, a pair of winter storms will bring a foot or more of snow to much of New England starting this weekend.

The first storm will travel up the East Coast on Saturday as a nor’easter, then an Alberta Clipper type storm will follow on Monday and Tuesday. The second storm could be the more potent one, with higher winds and disrupting the work-week.

Here are the currently forecast snow totals ending next Wednesday morning, Jan. 28 (graphic courtesy of Weatherbell.com, click for full-size):

Despite moderate light pollution here in Huntsville, Alabama, I was able to capture 1.9 hours of camera frames to make this time lapse video of Comet Lovejoy last evening. Some thin cirrus clouds and various satellites also pass by. The faint tail extends to the left of the nucleus, and if you watch closely you can see the comet traveling relative to the stars immediately surrounding it:

Constructed from 480 10-sec exposures taken every 14 sec. taken with a Canon 6D, Canon 85mm f/1.2 lens wide open, ISO 400, using an AstroTrac to roughly track the stars. Best viewed full-screen.

I’m seeing a flurry of news articles lately casting conservatives as closet believers in human-caused climate change who are struggling to formulate a global warming policy that is smart, but without looking like Liberals in the process.

Also, Pope Francis, after being advised by a committee of the most left-leaning global warming “experts” one could find, has decided to write an encyclical on global warming and the environment to be released later this year.

This all resonates with under-informed voters who think we already have the infrastructure to sustainably collect and distribute methane emissions from unicorn herds, and who believe solar freakin’ roadways are a good idea.

OK, maybe that was too snarky. I’m referring to those who believe that wind and solar really do provide reasonably priced, large scale alternatives to fossil fuels.

Except that solar and wind do not accomplish this. On an equalized basis, the cost of wind and solar is many times (as much as 10x to 30x) higher than fossil fuels, and we can’t get enough of those renewables to meet a substantial fraction of global energy demand anyway.

Remember, energy isn’t just needed for transportation and home heating/cooling and powering our lights and electronic devices. It’s needed for everything humans do, and when you make it much more expensive, life becomes harder for everyone. Call it trickle-down poverty.

I really don’t know what the underlying motivation of the GOP and the Pope is, but if they really care about the poor, they won’t force them further into poverty – and kill millions unnecessarily – by following a pipe dream which only enriches the renewable snake oil salesmen.

Yes, fossil fuels are a finite resource which will eventually need to be supplanted by other energy sources. But without widespread embrace of nuclear power, those energy sources do not yet exist in abundance or at low cost.

And if there one thing we know that kills poor people, its poverty. The Pope claims he is merely following biblical teaching to help the poor. But the bible teaches us to help to those who cannot help themselves. It doesn’t say to institute government regulations that make poverty even worse.

And in order to share our wealth with the poor, that wealth has to be generated in the first place.

First, do no harm. It’s really not rocket science. The GOP should not (nor should anyone else) accept the premise and narrative dictated to it by journalism majors.

Expensive energy kills people. UNICEF estimates 22,000 children die each day due to poverty. In contrast, no one is known to have ever died due to human-induced climate change. I predict that modest warming (whatever its cause) and more CO2 will turn out to be better for life on Earth.

Now, GOP, go grow a pair, and spread the word. The moral high ground is yours for the taking.

OR: Why I Should Have Been an Engineer Rather than a Climate Scientist

I’ve been inundated with requests this past week to comment on the NOAA and NASA reports that 2014 was the “hottest” year on record. Since I was busy with a Japan space agency meeting in Tokyo, it has been difficult for me to formulate a quick response.

Of course, I’ve addressed the “hottest year” claim before it ever came out, both here on October 21, and here on Dec. 4.

In the three decades I’ve been in the climate research business, it’s been clear that politics have been driving the global warming movement. I knew this from the politically-savvy scientists who helped organize the U.N.’s process for determining what to do about human-caused climate change. (The IPCC wasn’t formed to determine whether it exists or whether is was even a threat, that was a given.)

I will admit the science has always supported the view that slowly increasing carbon dioxide levels in the atmosphere from burning of fossil fuels should cause some warming, but the view that this would is any way be a bad thing for humans or for Nature has been a politically (and even religiously) driven urban legend.

I am embarrassed by the scientific community’s behavior on the subject. I went into science with the misguided belief that science provides answers. Too often, it doesn’t. Some physical problems are simply too difficult. Two scientists can examine the same data and come to exactly opposite conclusions about causation.

We still don’t understand what causes natural climate change to occur, so we simply assume it doesn’t exist. This despite abundant evidence that it was just as warm 1,000 and 2,000 years ago as it is today. Forty years ago, “climate change” necessarily implied natural causation; now it only implies human causation.

What changed? Not the science…our estimates of climate sensitivity are about the same as they were 40 years ago.

What changed is the politics. And not just among the politicians. At AMS or AGU scientific conferences, political correctness and advocacy are now just as pervasive as as they have become in journalism school. Many (mostly older) scientists no longer participate and many have even resigned in protest.

Science as a methodology for getting closer to the truth has been all but abandoned. It is now just one more tool to achieve political ends.

Reports that 2014 was the “hottest” year on record feed the insatiable appetite the public has for definitive, alarming headlines. It doesn’t matter that even in the thermometer record, 2014 wasn’t the warmest within the margin of error. Who wants to bother with “margin of error”? Journalists went into journalism so they wouldn’t have to deal with such technical mumbo-jumbo. I said this six weeks ago, as did others, but no one cares unless a mainstream news source stumbles upon it and is objective enough to report it.

In what universe does a temperature change that is too small for anyone to feel over a 50 year period become globally significant? Where we don’t know if the global average temperature is 58 or 59 or 60 deg. F, but we are sure that if it increases by 1 or 2 deg. F, that would be a catastrophe?

Where our only truly global temperature measurements, the satellites, are ignored because they don’t show a record warm year in 2014?

In what universe do the climate models built to guide energy policy are not even adjusted to reflect reality, when they over-forecast past warming by a factor of 2 or 3?

And where people have to lie about severe weather getting worse (it hasn’t)? Or where we have totally forgotten that more CO2 is actually good for life on Earth, leading to increased agricultural productivity, and global greening?:

It’s the universe where political power and the desire to redistribute wealth have taken control of the public discourse. It’s a global society where people believe we can replace fossil fuels with unicorn farts and antigravity-based energy.

Feelings now trump facts.

At least engineers have to prove their ideas work. The widgets and cell phones and cars and jets and bridges they build either work or they don’t.

In climate science, whichever side is favored by politicians and journalism graduates is the side that wins.

And what about those 97% of scientists who agree? Well, what they all agree on is that if their government climate funding goes away, their careers will end.

When it gets as cold as it has been lately (even here in Alabama), I like to find ways to take advantage of it. When I lived in the Upper Peninsula of Michigan 40 years ago, it was card games, beer, and snowmobiles (too often in that order).

Back in November in Alabama it was frost flowers. Today, it’s ice spikes.

Ice spikes form in bird baths and other rigid water containers when a layer of ice on the water thickens, expands, and forces water underneath to spurt up through a small hole that forms naturally in the ice. Some people have found them on their refrigerator ice cubes, although they tend to form more readily with distilled water than with tap water.

I tried my hand at making them two nights ago with the intent of getting better time lapse photography than I have found so far. I got two or three small ones to grow (video at the end of this post). But it was already 15 deg F when I started, and then 5 deg. F by morning, while a more optimum temperature is supposed to be about 20 deg. F.

Ice spikes have even been studied scientifically, at CalTech in Pasadena (yup, the Big Bang Theory nerds at it again). Their experiments were mostly in ice cube trays in a freezer.

But the more spectacular spikes I’ve found on the web have grown in large, shallow containers, mostly bird baths (the first pair below is, coincidently, from here in Huntsville 4 years ago, and the person grew them 2 nights in a row):

Note in rare cases an inverted pyramid of ice forms.

From reading some of what has been written on the physics of their formation, I think a missing ingredient is a heat source from below. Virtually all of the examples on the web have no snow on the ground, and the container almost always has a way of being kept warm from beneath. The water under the thickening ice must stay warm enough to feed the ice tube that forms, without the tube freezing shut. So, most of the instances of large ice spikes reported are from regions where the ground stays relatively warm. For example, cave temperatures here in Huntsville run around 60 deg. F, so the ground here remains quite warm through the winter.

Last night I tried again with a large tray like those found under large plant pots, sitting on a thick slab of Styrofoam, and used a three-probe quality digital thermometer to monitor temperatures. Without a heat source below, the water at the bottom of the 18” diameter shallow plastic tray rapidly approached 32 deg. F, and the surface of the water formed a uniformly thick sheet of ice. No spikes.

So, exactly how a small hole forms and is maintained as most of the ice thickens and the spike grows remains a mystery to me, although I suspect a weak heat source at the bottom is key to growing large spikes.

The small ones I grew with distilled water are on the right side of the dark bowl in the time lapse video, below. (The large bowl to the right losing water is made of bamboo…I thought it looked cool when I bought it, but it leaks). I placed a chemical-type hand warmer under each bowl:

I thought it would be useful to again outline the basic reasons why different satellite global temperature datasets (say, UAH and RSS) produce somewhat different temperature trends.

They all stem from the fact that there is not a single satellite which has been operating continuously, in a stable orbit, measuring a constant layer of the atmosphere, at the same local time every day, with no instrumental calibration drifts.

Instead, what we have is multiple satellites (we use 14 of them for the UAH processing) with relatively short lifetimes (2 to 16+ years), most of which have decaying orbits which causes the local time of measurement to slowly change over the years, slightly different layers sampled by the earlier (pre-1998) MSU instruments compared to the later (post-1998) AMSU instruments, and some evidence of small calibration drifts in a few of the instruments.

An additional complication is that subsequent satellites are launched into alternating sun-synchronous orbit times, nominally 1:30 a.m. and p.m., then 7:30 a.m. and p.m., then back to 1:30 a.m. and p.m., etc. Furthermore, as the instruments scan across the Earth, the altitude in the atmosphere that is sampled changes as the Earth incidence angle of view changes.

All of these effects must be accounted for, and there is no demonstrably “best” method to handle any of them. For example, RSS uses a climate model to correct for the changing time of day the observations are made (the so-called diurnal drift problem), while we use an empirical approach. This correction is particularly difficult because it varies with geographic location, time of year, terrain altitude, etc. RSS does not use exactly the same satellites as we do, nor do they use the same formula for computing a lower tropospheric (“LT”) layer temperature from the different view angles of AMSU channel 5.

We have been working hard on producing our new Version 6 dataset, revamping virtually all of the processing steps, and it has taken much longer than expected. We have learned a lot over the years, but with only 2-3 people working part time with very little funding, progress is slow.

In just the last month, we have had what amounts to a paradigm shift on how to analyze the data. We are very hopeful that the resulting dataset will be demonstrably better than our current version. Only time will tell.

2014 was Third Warmest Year Since 1979, but Just Barely
(with input from John Christy and Phil Gentry)

The Version 5.6 global average lower tropospheric temperature (LT) anomaly for December, 2014 is +0.32 deg. C, essentially the same as the November value of +0.33 deg. C (click for full size version):

The global, hemispheric, and tropical LT anomalies from the 30-year (1981-2010) average for the last 12 months are:

YR MON GLOBAL NH SH TROPICS
2014 1 +0.291 +0.387 +0.194 -0.029
2014 2 +0.170 +0.320 +0.020 -0.103
2014 3 +0.170 +0.338 +0.002 -0.001
2014 4 +0.190 +0.358 +0.022 +0.092
2014 5 +0.326 +0.325 +0.328 +0.175
2014 6 +0.305 +0.315 +0.295 +0.510
2014 7 +0.304 +0.289 +0.319 +0.451
2014 8 +0.199 +0.244 +0.153 +0.061
2014 9 +0.294 +0.187 +0.401 +0.181
2014 10 +0.365 +0.333 +0.396 +0.189
2014 11 +0.329 +0.354 +0.303 +0.247
2014 12 +0.320 +0.464 +0.177 +0.298

Notes on data released Jan. 6, 2015:

2014 was the third warmest year in the 36-year global satellite temperature record, but by such a small margin (0.01 C) as to be statistically similar to other recent years, according to Dr. John Christy, a professor of atmospheric science and director of the Earth System Science Center at The University of Alabama in Huntsville. “2014 was warm, but not special. The 0.01 C difference between 2014 and 2005, or the 0.02 difference with 2013 are not statistically different from zero. That might not be a very satisfying conclusion, but it is at least accurate.”

The 2014 average temperature anomaly is also in keeping with temperatures since late 2001, when the global average temperature rose to a level that is generally warmer than the 30-year baseline average. The most recent 13 complete calendar years, from 2002 through 2014, have averaged 0.18 C (about 0.33 degrees Fahrenheit) warmer than the 30-year baseline average, while the global temperature trend during that span was a warming trend at the rate of +0.05 C per decade — which is also statistically insignificant.

Compared to seasonal norms, the coldest annual average temperature on Earth throughout 2014 was just south of Wilmar, Minnesota. The average 2014 temperature there was –1.27 C (about 2.29 degrees F) colder than normal. The ‘warmest’ place throughout 2014 was just south of the North Pole along the International Date Line. Temperatures there averaged 1.65 C (about 2.97 degrees F) warmer than normal for the year.

Annual Global Temperature Anomalies, ranked

1. 1998 0.42
2. 2010 0.40
3. 2014 0.27
4. 2005 0.26
5. 2013 0.24
6. 2002 0.22
7. 2009 0.21
8. 2007 0.20
9. 2003 0.19
10. 2006 0.19
11. 2012 0.17
12. 2011 0.13
13. 2004 0.11
14. 2001 0.11
15. 1991 0.02
16. 1987 0.01
17. 1995 0.01
18. 1988 0.01
19. 1980 -0.01
20. 2008 -0.01
21. 1990 -0.02
22. 1981 -0.05
23. 1997 -0.05
24. 1999 -0.06
25. 1983 -0.06
26. 2000 -0.06
27. 1996 -0.08
28. 1994 -0.11
29. 1979 -0.17
30. 1989 -0.21
31. 1986 -0.24
32. 1993 -0.25
33. 1982 -0.25
34. 1992 -0.29
36. 1985 -0.31
37. 1984 -0.35

With a global average temperature that was 0.32 C (about 0.58 degrees Fahrenheit) warmer than seasonal norms, December 2014 trailed only December 2003, which averaged 0.37 C (about 0.67 degrees Fahrenheit) warmer than seasonal norms, among the warmest Decembers in the satellite temperature record. While December 2014 ranked second warmest for both the globe and the Northern Hemisphere, it was only the sixth warmest December in the tropics despite an El Niño Pacific Ocean warming event that seems to be forming there.

Warmest Decembers (1979-2014)
(Global average, warmer than seasonal norms)

1. 2003 +0.37 C
2. 2014 +0.32 C
3. 1987 +0.27 C
2013 +0.27 C
5. 2009 +0.24 C
6. 2012 +0.23 C
7. 1997 +0.22 C
2006 +0.22 C
9. 1998 +0.19 C
2005 +0.19 C

Compared to seasonal norms, the coldest place in Earth’s atmosphere in December was in northwestern Greenland, where temperatures were as much as 2.70 C (about 4.86 degrees Fahrenheit) colder than seasonal norms. Compared to seasonal norms, the warmest departure from average in December was in central Russia, north of the town of Yeniseysk. Temperatures there were as much as 2.75 C (about 4.86 degrees Fahrenheit) warmer than seasonal norms.

The global image for December should be available in the next day or so here.

Popular monthly data files (these might take a few days to update):

uahncdc_lt_5.6.txt (Lower Troposphere)
uahncdc_mt_5.6.txt (Mid-Troposphere)
uahncdc_ls_5.6.txt (Lower Stratosphere)