With Global Warming, Will Cold Outbreaks Be Less Common?

Maybe, maybe not. There is a new paper that looks at what climate scientists call “synoptic midlatitude temperature variability” and the rest of us call “cold snaps” and “heat waves.” The term “synoptic” simply means over a reasonably large area like you might expect a cold snap or heat wave to be. Specifically, the paper (Physics of Changes in Synoptic Midlatitude Temperature Variability, by Tapio Schneider, Tobias Bischoff and Hanna Plotka, published in Journal of Climate) concludes that as human-caused greenhouse gas pollution increases, the frequency of cold snaps in the northern hemisphere will go down. Naturally, as temperatures warm up we would expect the highs to get higher, the averages to be higher, and the lows to be higher as well (and thus fewer cold spells). But the new research actually argues that the cold spells (the cold extremes at synoptic spacial scales) will become even less common. This is potentially controversial and conflicts with other recently published research.

The paper is rather technical so, I’ll give you the abstract so you can go take a class in climate science, then come back and read it:

This paper examines the physical processes controlling how synoptic midlatitude temperature variability near the surface changes with climate. Because synoptic temperature variability is primarily generated by advection, it can be related to mean potential temperature gradients and mixing lengths near the surface. Scaling arguments show that the reduction of meridional potential temperature gradients that accompanies polar amplification of global warming leads to a reduction of the synoptic temperature variance near the surface. This is confirmed in simulations of a wide range of climates with an idealized GCM. In comprehensive climate simulations (CMIP5), Arctic amplification of global warming similarly entails a large-scale reduction of the near-surface temperature variance in Northern Hemisphere midlatitudes, especially in winter. The probability density functions of synoptic near-surface temperature variations in midlatitudes are statistically indistinguishable from Gaussian, both in reanalysis data and in a range of climates simulated with idealized and comprehensive GCMs. This indicates that changes in mean values and variances suffice to account for changes even in extreme synoptic temperature variations. Taken together, the results indicate that Arctic amplification of global warming leads to even less frequent cold outbreaks in Northern Hemisphere winter than a shift toward a warmer mean climate implies by itself.

Why is this controversial? Because we have seen research in recent years indicating that with Arctic Amplification (the Arctic getting relatively warmer than the rest of the planet as global warming commences) the manner in which warm air is redistributed from sun-facing Equatorial regions towards the poles changes, which in turn changes the behavior of the Polar jet stream. Rather than being relatively straight as it rushes around the globe, separating temperate and sub-polar regions (and defining the boundaries of trade winds, and moving along storms) it is thought that the jet stream has become more often very curvy, forming what are called Rossby waves. These waves, recent research has suggested, can become stationary and the wind within the waves moves relatively slowly. A curvy jet stream forms meteorological features such as the “ridiculously resilient ridge” which has brought California nearly continuous dry conditions for at least two years now, resulting in an unprecedented drought. A curvy jet stream also forms meteorological features called “troughs” such as the excursion known last year (incorrectly) as the Polar Vortex, which also returned in less severe form this year; a bend in the jet stream that brings polar air farther south than usual, causing a synoptic cold spell of extensive duration. These changes in the jet stream also seem to have brought some unusual winter weather to the American Southeast last year, and have been implicated in steering Super Storm Sandy into the US Northeast a few years ago. And that flood in Boulder, and the flood in Calgary, and the June Of All Rain here in Minnesota last year, and so on. This is the main global warming caused change in weather systems responsible for what has been termed “Weather Whiplash” and may rank up there with increased sea surface temperatures as factors underlying the observable, day to day effects of human caused climate disruption.

I’ve talked about jet streams, Rossby waves, and such in a few places:

Even more recently was a paper by Dim Coumou, Jascha Lehmann, and Johanna Beckmann, “The weakening summer circulation in the Northern Hemisphere mid-latitudes” that argued:

Rapid warming in the Arctic could influence mid-latitude circulation by reducing the poleward temperature gradient. The largest changes are generally expected in autumn or winter but whether significant changes have occurred is debated. Here we report significant weakening of summer circulation detected in three key dynamical quantities: (i) the zonal-mean zonal wind, (ii) the eddy kinetic energy (EKE) and (iii) the amplitude of fast-moving Rossby waves. Weakening of the zonal wind is explained by a reduction in poleward temperature gradient. Changes in Rossby waves and EKE are consistent with regression analyses of climate model projections and changes over the seasonal cycle. Monthly heat extremes are associated with low EKE and thus the observed weakening might have contributed to more persistent heat waves in recent summers.

Coumou notes that “when the great air streams in the sky above us get disturbed by climate change, this can have severe effects on the ground. While you might expect reduced storm activity to be something good, it turns out that this reduction leads to a greater persistence of weather systems in the Northern hemisphere mid-latitudes. In summer, storms transport moist and cool air from the oceans to the continents bringing relief after periods of oppressive heat. Slack periods, in contrast, make warm weather conditions endure, resulting in the buildup of heat and drought.” Co-author Jascha Lehmann adds, “Unabated climate change will probably further weaken summer circulation patterns which could thus aggravate the risk of heat waves. Remarkably, climate simulations for the next decades, the CMIP5, show the same link that we found in observations. So the warm temperature extremes we’ve experienced in recent years might be just a beginning.”

These seem to be conflicting views.

So, how do the scientists who have published the recent paper that stands in stark contrast with these other recent findings explain the difference? I asked lead author Tapio Schneider to comment.

He told me that yes, there is a tension between the other work (the Comou et al paper) and his work, but there is also overlap and similarity. “Coumou et al. state that amplified warming of the Arctic should lead to reduced zonal jet speeds at fixed levels in the troposphere. This is an uncontroversial and well known consequence of thermal wind balance. Then they say that the reduced zonal jet speeds may lead to reductions in eddy kinetic energy (EKE), which is a measure of Rossby wave amplitude. That this can happen is likewise well documented. What affects eddy kinetic energies is a quantity known as the mean available potential energy (MAPE), which depends on temperature gradients (which also affect jet speeds) and other quantities, such as the vertical temperature stratification. Coumou et al. focus only on one factor influencing the EKE, the temperature gradient.”

The tension, he told me, is in what the other researchers (Coumou et al) draw from their results. “They show that warm summer months usually are associated with low EKE in the current climate, consistent with common knowledge: unusually warm conditions are associated with relatively stagnant air. They use this correlation in the current climate to suggest that reduced EKE in a future climate may also imply more (monthly) heat waves. While intuitive, this is not necessarily so. They say their suggestion is not in contradiction with our results because we considered temperature variability on shorter timescales (up to about two weeks), while their suggestion for more heat waves is made for monthly timescales. However, why the longer timescales should behave so differently is not made clear. “

As an onlooker, I take the following from this. First, there may be differences in time (and maybe space) scales of the analyses that might make them less comparable than ideal. Second, Schneider and Bischoff seem to be emphasizing synoptic cold outbreaks specifically. Schneider told me that they did look at temperature variability over longer time scales, but that did not make it into the paper. He said, “Even on monthly timescales, midlatitude temperature variance generally decreases as the climate warms, with a few regional exceptions (e.g., over Europe).”

Also, note that Schneider, Bischoff and Plotka, in this paper, do not address the specific problem of stationary Rossby waves, which probably has more to do with rainfall (lacking or heavy) than temperature, but is an important part of current changes in weather.

There has been some additional criticism of Schneider’s work on social media, etc. and perhaps the most significant one is this: Schneider, Bischoff and Plotka may have oversimplified the conditions in at least one of their models by leaving out continents. Also, Schneider et al has been picked up by a few of the usual suspects as saying that climate change will result in milder winters or less severe storms. This is not actually what the paper says. When people think "milder winter" they usually mean fewer severe storms, but various lines of evidence suggest that the notheastern US will experience more storms. For, example, see "Changes in U.S. East Coast Cyclone Dynamics with Climate Change" and "Global Warming Changing Weather in the US Northeast."

UPDATE: I've received a comment from Dim Coumou pertaining to the differences between Schneider Et Al and Comou Et Al:

I see mostly overlap between the two studies, whereby ours really is an observational study analyzing data over the last 35 years (focusing on summers), and theirs is a theoretical and modeling study (focusing on winters). Interestingly both studies report similar dynamical changes but indeed come to somewhat different conclusions as to what this means for surface weather extremes.

We show that circulation (and notably EKE) has weakened in summer, that this has made weather more persistent and therefore favored the occurrence of prolonged heat waves in recent years. (We´re really focusing on present day climate and only show future projections for comparison with observations). As also discussed in our paper a drop in EKE leads to a reduction in weather variability on short timescales (less than a week) so this is consistent with the findings by Schneider et al. So indeed the issue of timescales is very important, and in my opinion prolonged extremes lasting several weeks are more important from an impact point of view.

Schneider, Bischoff and Plotka are well respected scientists and they are using methods that are generally accepted within climate science, yet have come to a conclusion different from what some of their colleagues have proposed. This is, in my opinion, a very good thing, and, certainly, interesting. I would worry if every climate scientist came up with the same result every time they tried something slightly different. The patterning (or changes in patterning) of air and sea currents under global warming has been the subject of a great deal of recent research, and there is strong evidence that changes are happening (such as in sea currents in the North Atlantic, and the jet stream effects discussed here) that have not been directly observed before. Because of the high level of internal (natural) variability, climate science works best when chunks of time 20 or 30 years long are considered. If we are seeing changes now that have really started to take off only five or ten years ago, and that are still dynamically reorganizing, how can the more ponderous, long term and large scale, thinking of climate science adjust and address those rapid changes? Well, we are seeing that process now in the climate change literature, and this paper is one example of it. I look forward to an honest, fair, and vigorous discussion in the peer reviewed literature.

Caption for the figure at the top of the post: FIG. 6. CMIP5 multimodel median values of 850-hPa potential temperature statistics for (left) DJF and (right) JJA. (a) Synoptic potential temperature variance u02 for the years 1980–99 of the historical simulations. (b) Per- centage change of the synoptic potential temperature variance u02 in the years 2080–99 of the RCP8.5 simulations relative to the years 1980–99 of the historical simulations shown in (a). (c) Percentage change of the squared meridional potential temperature gradient (›yu)2 in the years 2080–99 of the RCP8.5 simulations relative to the years 1980–99 of the historical simulations. (To calculate the gradients, mean potential temperatures were smoothed with a spherical harmonics filter that damped spherical wavenumbers greater than 6 and completely fil- tered out wavenumbers greater than 10.) (d) Percentage change of the squared mixing length L0 2 5 u0 2 /(›y u)2 implied by the variance and meridional potential temperature gradient, in the years 2080–99 of the RCP8.5 simulations relative to the years 1980–99 of the historical simulations. Synoptic potential temperature variations are bandpass filtered to 3–15 days. In the dark gray regions, topography extends above the mean 850-hPa isobar. The light gray bar blocks out the equatorial region, where potential temperature gradients are weak and their percentage changes become large.


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It is refreshing to see results that are not sticking with the norm and I hope to read more from Schneider, Bischoff and Plotka in the future. Can one assume then that the same differences of opinion would be seen when looking at Rossby waves as well?

By Keagan Loader … (not verified) on 31 Mar 2015 #permalink

I think that Schneider et al's paper is very complicated and what look at first like differences between their findings and other work is more a function of it taking a little longer to understand what they are saying.

See the comment aded above from Dim Coumou.

The weather WHIPLASH phenomenon implies that global warming is the cause of natural disasters in both hemispheres. My opinion is that earth adapted after ice age which has no more effect in the modern world. Is the concern relating to global warming not blown out of proportion as earth has the ability to embrace change. 15015964

Earth can certainly embrace change, yes. Organisms have more difficulty (they tend to be reduced in numbers and/or go extinct).

We've built numerous civilizations based on reliable access to fresh water and food supplies, and a fairly stable ocean level. When those change a good proportion of the human population will have increased hardships, from finding a new place to live in an already over-crowded country, to drought-induced famine. Those in richer developed countries will also be impacted (e.g. rising food prices, new foreign policies/wars from overseas socio-political turmoil brought on by displaced people) not to mention what will happen if our nations' breadbaskets on the prairies and in the mid-west have a few bad drought years.

By Dan Andrews (not verified) on 03 Apr 2015 #permalink

"Is the concern relating to global warming not blown out of proportion as earth has the ability to embrace change."

It's tempting to fall into this line of thinking, but I would urge you to consider another view. By saying that the earth "adapted" after the ice age, I think you're suggesting that climate fluctuations have always happened, so what's the big deal with this one? I would answer that climate changes don't just happen. Natural fluctuations still have causes, and by and large we have a pretty good handle on what those causes are. This is why most climate scientists (including me, although my interest is more in how climate affects other systems than in climate itself) think that the current pattern of change is due to human activity. No other explanation can really account for the full range of phenomena we are currently observing in the climate system. The shorter and more significant answer to your question is that, you're right, the earth will be fine. Humans, on the other hand, may have a much harder time adapting. I've seen credible estimates that suggest that 4 degrees of warming could reduce the human carrying capacity of the earth by half, from about 7.5 billions down to perhaps 3 or 4. I can only imagine the horrors that would occur as this massive depopulation proceeded. I'm sure it wouldn't be a simple case of natural decrease. At present GHG levels, we're already committed to a one degree increase in temperature -- it can't really be stopped at this point. This is a real problem.

I live in central South Africa in the Southern hemisphere. I think that global warming could be altering weather patterns all over the globe. In the past few years we have been experiencing great fluctuations in the normal weather pattern of our region. Winters arrived much later than usual and the temperatures in weren't as low as those we are used to during winter. Spring arrived earlier and Autumn much later, yet numerous irregular cold fronts passed over our region until almost midsummer. The rainfall pattern also changed. We have been experiencing dry summers in our region of late, as a result of poor rainfall, while other regions in South Africa experienced floods in the past few years due to abnormal heavy rainfall. Could this be an effect of changes in jet streams, or Rossby waves occurring in the Southern hemisphere or could there be another explanation for these changes in the weather patterns?

By AG Woodley - u… (not verified) on 04 Apr 2015 #permalink

The earth will survive the change in the temperature, but the organisms, especially humans, will not. In the past five mass extinctions have taken place and the causes were all natural. Currently the sixth and biggest mass extinction is taking place and the cause is global warming. Higher temperatures affects vulnerable organisms that cannot move to cooler areas, such as algae and organisms at the poles. The change in weather patterns due to changes in jet streams and Rossby waves can also affect organisms habitats and lead to extinction.

By u15035752 (not verified) on 05 Apr 2015 #permalink

One thing to consider is that, if the models of mid-tropospheric warming ever pan out, there would be a reduction in lapse rate. It's delta would be lattitude dependent; But this, in concert with a weakened horizontal gradient, might be expected to reduce the severity of storms in the mesoscale.

Synoptic wise, a completely weakend zonal wind and reduced surface 'venting' (effluence) due to kinks in the jet stream should lead to more stratiform type precipitation. I might surmize that some orography-induced global climate may even reverse -- Some deserts become Edens, Some golf courses will still need yet more water.

By Élan vital (not verified) on 05 Apr 2015 #permalink

Time is one thing we can be certain of. Time is changing and as it changes we can be certain that global warming is also going to change. My opinion is that if millions of years ago there was no global warming right now we are apart of the Earth's process of reaching an equilibrium. In certain areas it will get too hot I know ice caps are melting but in South Africa global warming is resulting in more rain as it is a country that's mostly in a plateau. This is also reducing desertification chances and increasing soil fertility.

By TRK Ngaka u15103634 (not verified) on 06 Apr 2015 #permalink

Reading about the fluctuations of various weather conditions around the world such as the droughts in Calafornia and the floods in Boulder and Calgary shows one how extreme the weather conditions can be and this swing of varying temperatures will affect various organisms as the organisms that previously lived in hot weather conditions cannot live there anymore and visa versa. Bacteria that previously couldn't live in areas that were too cold for them will now be able to thrive in those areas due to global warming. This will thus lead to more people being susceptible to contracting colds.

By u15077536 (not verified) on 06 Apr 2015 #permalink

Of course, I meant weakened *difluence*.

By Élan vital (not verified) on 06 Apr 2015 #permalink

are the researches done on how to prevent it from disrupting the nature any further?(u12294447)

By Nehemia Mokgaliphe (not verified) on 07 Apr 2015 #permalink

With consistent and increased global warming there will be harm towards the inhabitants of the earth, rather than the earth itself. However both will suffer harm. As temperatures increase there will be an increase in evapotranspiration which will cause drught and also a decrease in sea-levels as evapotranspiration will take place in underwater plant-life. This in turn will cause tidal waves due to the fluctuations of the water levels. u143018145

By Arthur Grüner … (not verified) on 07 Apr 2015 #permalink

The earth can emrace change, however we do not know if these changes will occur through catastrophic processes eradicating any form of life or whether a change will occur where life can hardly survive. u14301815

By Arthur Grüner … (not verified) on 07 Apr 2015 #permalink

After reading about the droughts in Calafornia and the floods in Boulder, one can see how severe the weather conditions are and thus these fluctuations in the weather affect many organisms. An example is that bacteria can now live in areas that were previously too cold for them and this is as a result of global warming and it's drastic effects. This thus results in more people becoming more susceptible to contracting colds.

By u15077536 (not verified) on 07 Apr 2015 #permalink

If the cold virus is affected by rising temperature the overall cases would decline because a study at the university of Yale found that low temperature dampen natural defenses against viruses. I also agree with the comments that new bacteria can thrive in warm conditions that was previously too cold.


If the cold virus is affected by rising temperature the overall cases would decline because a study at the university of Yale found that low temperature dampen natural defenses against viruses. The human body will therefor be more vulnerable for colds. Is global temperature still on the rise or is it stabilizing?.


If the cold virus is affected by rising temperature the overall cases would decline because a study at the university of Yale found that low temperature dampen natural defenses against viruses. The human body will therefor be more vulnerable for colds. Is global temperature still on the rise or is it stabilizing?


Only time will tell whether there will be less cold outbreaks in the Northern hemisphere however the Earth has undergone many climate changes and is known to adjust. That being said all living micro-organsms can only wait and see whether they are strong enough to adapt to these changes.

By u15006680 (not verified) on 07 Apr 2015 #permalink

I would like to know how global warming got so bad and if anything could of been done to have stopped it from reaching such extreme proportions to what it is today? If so what could these measures have been and what can we as the public do to ame sure to try limit global warming as mucg as possible?

I agree that Earth can sustain itself and that global warming has occured on Earth naturally. However, we as humans are accelerating global warming which in my opnion is not natural or a good thing and i feel this will be a serious concern in the future. Am i not correct in saying this, and will global warming if it carries on like this, lead to the extinction of the human race in the future no matter how far in the future that might be?

By Ethanne Liam Soar (not verified) on 08 Apr 2015 #permalink

Will global warming decrease cold outbreaks?. In short yes and the evidence is there already. Will earth survive such a change?. I agree the planet can "embrace change" but a solid conclusion cannot be drawn based on past observations. Will global warming cause human extinction?. I do not think so. With extinction we at looking at total annihilation of human beings, that is quite a task. If humans can build a space station that can enable them to exist on Mars for certain period of time surely they can survive global warming. We are designed to think fast and adapt. Certainly not every human will pull through maybe more than half of the population will perish but not everyone. Global warming will lead to survival of the fittest.

By u15139264 (not verified) on 08 Apr 2015 #permalink

With 2014 recorded as the hottest year, climate change has led to heavier than normal snowfalls in some parts of the world. The warmer water has an influence on the moisture in the air and hence the development of ice. The current trends in weather patterns are indicating a decrease in the frequency of cold outbreaks, rain etc. I agree that the cold outbreaks will decrease but I expect them to be more severe when they do occur. More research is required and with satellites deployed over the world, it will surely assist scientists in their research.

By Louise Botha (not verified) on 10 Apr 2015 #permalink

According to research done by scientists at ETH Zurich and California Institute of Technology the frequency of cold snaps will decrease as the climate is warming. Their argument is based on the fact that higher latitudes are warming faster than lower ones, meaning that the temperature difference between the equator and the poles are decreasing leading to more uniform air temperatures.

Given that global warming increases the average energy on the earth's surface, shouldn't temperature fluctuations become more common and therefore the exact opposite happening?

By u15108342 (not verified) on 10 Apr 2015 #permalink

Hi everyone! I am doing a research term project on the effects of global warming on our droughts and food scarcity catastrophe. How will these issues effect us in the near future and what will be the severity of these problems? We are already realizing the damage of the near-extinction of the honey bees. What more can we expect to see in our lifetime? How can we change this or is it too late too change it?

By Kayla Parisi (not verified) on 11 Apr 2015 #permalink

This article explains something that I have never considered before, it is an interesting proposal that the cold snaps will become less frequent. In my opinion as climate change continues to accelerate, the over all temperatures will increase meaning less chances for cold snaps but weather phenomena when they occur will become more severe as the climate becomes more unstable. I did a science expo on global warming in high school - here I was able to to compare daily temperature readings over a period of 21 years - I not only found that there was in fact a increasing trend line that showed an increase of 0.5 degrees Celsius, but also that there had been a shift in the weather patterns of my area. Even over the last few years I have seen a drastic change in weather patterns where I live as a result my area has experienced much more rain than previous years with more frequent flash floods. I have read many articles that show that weather phenomena such as cyclones are becoming stronger and more frequent as well as the discussions on England's record snowfall, they show how much our climate has changed over the years. So perhaps we will have fewer cold snaps but when they do occur I believe that they will be more severe as climate change progresses.

By Gina (15008682) (not verified) on 12 Apr 2015 #permalink

Most people are concerned about global warming being the beginning of the Apocalypse, but according to my understanding of how the earth have been regulating itself, this might be a way in which the earth is changing into new era. It can have positive impact in the future that will positively affect new generation, probably new human species.


Percy, do you think that the changing climate will be good for plants and animals that are adapted for cooler temperatures? How will warmer temperatures affect agriculture?

Do you have an idea how many generations it might take for new human species to evolve?

GregH there are so many things that nature can do without science predicting them. Evolution might take place in a faster rate than we anticipated, maybe stimulated by global warming. Remember that Niles Eldredge and Stephen Jay Gould's theory of punctuated equilibrium is still a theory that was never disproved!

GregH there are so many things that nature can do without science predicting them. Evolution might take place in a faster rate than we anticipated, maybe stimulated by global warming. Remember that Niles Eldredge and Stephen Jay Gould's theory of punctuated equilibrium is still a theory that was never disproved!


I think that evolution is linked to global warming because as the global temperature changes due to global warming the living conditions of animals also change. Over time this will cause animals to evolve to become better suited to their environment

By Bennett M (not verified) on 14 Apr 2015 #permalink

I agree that planet earth will embrace the changes, but will organisms such as the human race do so also? Global warming is a serious case and wether it changes the weather and its cold outbreaks or not we are responsible for it and will have numerous effects on the whole society.

In my opinion i do think that cold outbreaks will be less common because the weather seems to be getting hot and hotter every year. Another reason is that the Earth is getting close to the sun as it orbits everyday.


By Shobede Q.K (not verified) on 15 Apr 2015 #permalink

I think that although the climate is getting increasingly warmer, I believe that nature could be very unpredictable and that we can not for certain say that cold outbreaks will become less common. 15055940

Global warming refers to the increase in the global average temperature. These increases throw weather systems out of balance which can result in extreme changes in weather patterns, which can include extreme heat or cold outbreaks coupled to droughts and periods of intense heat.

By ConradiePJ-u15018050 (not verified) on 15 Apr 2015 #permalink

for me this is controversial,Schneider paper is very complicated,the findings are not the same.I Disagree with the findings that global warming cause of natural disasters in hemisphere,earth can have some changes now and again.

By mabena phumela (not verified) on 16 Apr 2015 #permalink

Although it will be hard for species to adapt to the new temperature and weather conditions, most species will be able to survive the conditions. Species can survive to live on coldness than hotness. Some may elvolve to become some new species in order to adapt to the new environment.u13127846

By Mamushiana (not verified) on 17 Apr 2015 #permalink