I received the following question from a loyal, frozen reader:

Uff da, Dr. Roy! Exactly how does global warming cause 50 deg. below zero in Minnesota? – Lars Olsen

Excellent question, Lars! Let me climb down out of my ivory tower and I will attempt to explain it to you….

You see, right now there is a little bit of open water in the Arctic Ocean that isn’t frozen over. This is a bad thing, because Beluga whales are known to surface in these waters where they produce emissions of a potent greenhouse gas, methane.

These methane emissions then drift over land. This, in turn, causes herds of caribou (which have a keen sense of smell), to start moving in a clockwise direction (in the northern hemisphere), transferring anticyclonic vorticity from the Earth to the atmosphere.

As every meteorologist knows, anticyclonic vorticity causes atmospheric high pressure to form, which drags cold air down from the upper atmosphere (kind of like in the Al Gore docudrama, Day After Tomorrow).

In response to this Beluga-Caribou Forcing, polar vortex butterflies start flapping their wings harder. These very rare creatures are seldom seen, but global warming-cooling theory suggests there are trillions of them.
As they do so, the Polar Vortex^® starts spinning erratically and moves southward.

Why southward, you ask? Silly Lars, every direction from the north pole is southward. Sheesh. Now quit interrupting…

What then makes the whole process really get energized, though, is the billions of polar bears that have died, and are no longer blocking the cold Arctic winds from plunging into Minnesota.

Concern over the billions of dead polar bears then causes humans to do stupid things to the environment (as part of their fundraising activities) which then causes the oceans to warm, if ever so slightly.

Scientists do not yet understand why humans behave in this way, but there is sufficient anecdotal and photographic evidence to conclude that they really do:

Finally, all of these effects, together, are believed to be part of a positive feedback loop:

Stupid people warming oceans leads to
=> less sea ice
=> whale farts
=> spinning caribou
=> polar vortex butterfly stimulation
=> reduced wind blocking (dead polar bears)
=> (more) stupid people warming the oceans…

…and the whole process starts over.

So there you have it. This is how global warming is believed to cause 50 below zero temperatures in Minnesota.

And that’s a fact, Jack.

After this next storm system exits the Great Lakes in a couple of days, cold arctic air is going to gradually return to the Eastern U.S., and especially the upper Midwest and Great Lakes.

The 8-day forecast for Thursday night (next week) has -50 deg. F temperatures knocking on the door in Minnesota, and below-freezing temperatures pushing into northern Florida. Awesome GFS model forecast imagery (paywalled) courtesy of our friends at WeatherBELL:

Time to fire up your SUV, sacrifice the groundhog, or something.

This morning’s NASA MODIS image of the northeast U.S., true color (which I’ve enhanced a little…click for large version).

I put together this time lapse of twice-daily images from NASA MODIS (flying on the Terra and Aqua satellites), between 11 Dec. 2013 and 15 Feb. 2014. This is the “721” enhancement, which better separates clouds (white) from snow/ice (blue). (Sorry, but it was too much trouble to put a date stamp on every frame).

Here’s some video I took of large ice falling off a 1,500 ft. TV tower I live next to. This happens every few years after a snowstorm, and is mostly due to supercooled cloud water freezing to the tower and support cables (we didn’t have an ice storm…but did have 6 inches of snow). The falling ice sounds a little like a propeller plane coming in to land.

Best watched full-screen, with HD enabled, turn up your sound, and don’t miss the ending.

In another silly pseudo-science rambling, the President’s science advisor, John Holdren, has recently stated, “Weather practically everywhere is being caused by climate change.”

Drought in California. Record snows in the East. It’s tempting for many to blame it all on our use of fossil fuels.

What Causes Weather?
Let’s start with the basics. Weather is caused by energy imbalances, primarily (1) between the solar heated surface of the Earth and the atmosphere above it, and (2) between different geographic regions (e.g. the tropics vs. high latitudes; the warm oceans versus cold continents in winter).

These energy imbalances have associated temperature differences, which in turn cause atmospheric circulation systems which form clouds, precipitation, and high and low pressure systems.

How much energy is involved? On a global basis the average rate of solar energy absorbed by the Earth is estimated to be about 240 Watts per sq. meter. In order for the climate system to stay at the same average temperature year after year, the Earth has to lose exactly the same amount of energy (240 W m^-2) to outer space, in the form of infrared energy.

It’s all about the energy…and especially about imbalances in energy, which causes “weather” as the ocean and atmosphere seek to reduce those imbalances. On a local basis, those imbalances can be tens or even hundreds of watts per sq. meter.

So, How Much of Weather Could be Caused by Manmade Climate Change?
Our best estimate of how much the climate system has been perturbed from energy balance comes from the slow warming of the oceans, which since the 1950s equates to a 1 part in 1,000 energy imbalance (say, if 240 W m^-2 of solar energy has been absorbed on average, 239.75 W m^-2 has been lost to space…the slight ~0.25 W m^-2 imbalance leads to slow warming).

Now, how exactly can a 1 part in 1,000 energy imbalance lead Holdren to state, “Weather practically everywhere is being caused by climate change”? Well, all I can think of is that his statement is not based in science.

Maybe that imbalance in recent years is somewhat more…say 2 parts in 1,000 (about a 0.5 W m^-2 imbalance). But even that depends upon whether you believe in the measurements of tiny, multi-decadal oceanic warming trends of tenths or hundredths of a degree (depending on depth).

And it’s far from clear that even that is entirely our fault.

Now, how that tiny imbalance gets translated into a change in weather is, admittedly, not well understood. But, ultimately, weather is still related to energy imbalances, and mankind’s role in changing those rates of energy flow is miniscule.

You might say, “But what about global warming causing a warmer Gulf Stream, which then clashes with the cold air masses and makes bigger East Coast snowstorms?” The trouble with that argument is that “global warming” warms those winter air masses more than it warms the oceans, reducing the temperature contrast. So, if the opposite is happening this winter, then it’s not due to global warming.

The idea that any of the weather we are seeing is in any significant way due to humanity’s greenhouse gas emissions verges on irrationality.

Yesterday’s NASA MODIS imagery from the Terra and Aqua satellites revealed relatively cloud free conditions over Lake Superior, which is unusual since the cold air sitting over the relatively warmer ice and water causes almost continuous cloud formation. Here’s the Aqua MODIS true-color image, which I’ve enhanced somewhat (click for large version):

The MODIS “721” color enhancement product does a better job of distinguishing between clouds and ice (click for large version):

Note that it is difficult to distinguish between open water and new ice formed during low wind conditions, which is relatively clear.

GLERL’s model analysis suggests about 94.3% ice coverage of Lake Superior today, and some lake watchers are forecasting complete coverage in the near future.

I’m seeing a lot of wrangling over the recent (15+ year) pause in global average warming…when did it start, is it a full pause, shouldn’t we be taking the longer view, etc.

These are all interesting exercises, but they miss the most important point: the climate models that governments base policy decisions on have failed miserably.

I’ve updated our comparison of 90 climate models versus observations for global average surface temperatures through 2013, and we still see that >95% of the models have over-forecast the warming trend since 1979, whether we use their own surface temperature dataset (HadCRUT4), or our satellite dataset of lower tropospheric temperatures (UAH):

Whether humans are the cause of 100% of the observed warming or not, the conclusion is that global warming isn’t as bad as was predicted. That should have major policy implications…assuming policy is still informed by facts more than emotions and political aspirations.

And if humans are the cause of only, say, 50% of the warming (e.g. our published paper), then there is even less reason to force expensive and prosperity-destroying energy policies down our throats.

I am growing weary of the variety of emotional, misleading, and policy-useless statements like “most warming since the 1950s is human caused” or “97% of climate scientists agree humans are contributing to warming”, neither of which leads to the conclusion we need to substantially increase energy prices and freeze and starve more poor people to death for the greater good.

Yet, that is the direction we are heading.

And even if the extra energy is being stored in the deep ocean (if you have faith in long-term measured warming trends of thousandths or hundredths of a degree), I say “great!”. Because that extra heat is in the form of a tiny temperature change spread throughout an unimaginably large heat sink, which can never have an appreciable effect on future surface climate.

If the deep ocean ends up averaging 4.1 deg. C, rather than 4.0 deg. C, it won’t really matter.

The Version 5.6 global average lower tropospheric temperature (LT) anomaly for January, 2014 is +0.29 deg. C, little changed from December (click for full size version):

The global, hemispheric, and tropical LT anomalies from the 30-year (1981-2010) average for the last 13 months are:

YR MON GLOBAL NH SH TROPICS
2013 1 +0.497 +0.517 +0.478 +0.386
2013 2 +0.203 +0.372 +0.033 +0.195
2013 3 +0.200 +0.333 +0.067 +0.243
2013 4 +0.114 +0.128 +0.101 +0.165
2013 5 +0.082 +0.180 -0.015 +0.112
2013 6 +0.295 +0.335 +0.255 +0.220
2013 7 +0.173 +0.134 +0.211 +0.074
2013 8 +0.158 +0.111 +0.206 +0.009
2013 9 +0.365 +0.339 +0.390 +0.190
2013 10 +0.290 +0.331 +0.249 +0.031
2013 11 +0.193 +0.160 +0.226 +0.020
2013 12 +0.266 +0.272 +0.260 +0.057
2014 1 +0.291 +0.386 +0.196 -0.027

The global image for January 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)

Yes, Virginia, it really has been a cold winter.

The winter months of December 2013 and January 2014 averaged over the contiguous 48 United States were the 3rd coldest Dec/Jan in the last 30 years.

The analysis is based upon ~350 NOAA/NWS stations that measure temperatures every 6 hours (or more frequently), many located at airports. This is different from the official NOAA temperature product (update not yet available), which is based upon daily max/min temperatures measured at 1,000+ co-op stations. Those stations have had large adjustments made due to (among other things) changing time of observation (TOBS) over the years.

Here’s a plot of the Dec/Jan averages for the last 41 years (click for large version):

An interesting feature is that 5 of the last 7 years have been below the 41-year average, which has happened only one other time in the 41-year period.

The data I use are adjusted for average spurious urban heat island (UHI) warming that increases with population density around the thermometer site. That relationship is shown at the end of this article. The analysis starts in only 1973 since that is the first year with a large amount of quality-controlled 6-hourly temperature data archived at NOAA.

So, does the cold winter disprove global warming theory? No more than an unusually warm winter proves the theory. It’s just what we used to call “weather”.

UPDATE: John Christy has been running NOAA’s USHCN station data, and with a couple days still missing from the end of January, it looks like the official data will have Dec/Jan (’13/’14) as the 4th (rather than 3rd) coldest in the last 30 years.