Are we about to enter another mini ice age ?

[knocker]

Of course we have with orbital variation. Are you suggesting that's the case now?

[The PIT]

Of course we have with orbital variation. Are you suggesting that's the case now?

No idea somebody may know.

[Methuselah]

Whatever one believes has greater effects, that was an excellently written and laid out post

There is much to think about and discuss about the roles of the sun, the arctic ice etc and one thing I would question here is that I would disagree about the changes in jet stream being strongest in the autumn.

It has been notable that there has been a distinct change at virtually all times of year with the jet stream being significantly further south quite linearly across the year than it was prior to the 2007 time.

I mentioned yesterday some of the solar/ENSO phase changes which have simultaneously occured in recent years along with the changes in ozone distribution as solar activity wanes which have affected stratospheric temperature profiles and consequently account (in part) for the much greater and more frequent Higher Latitude blocking periods that have occured across the whole of the NH since 2007.

On this basis we have seen the jet stream head south in later Spring on a few occasions now after a short period of mid latitude high pressure as the jet stream has briefly headed north after winter. That is, until this Spring of course and whilst we are still firmly entrenched in a cold blocking, southerly tracking jet stream regime.

I think we should conclude, thus far in recent years, that the changes in jet stream pattern and associated meridonality have been wholesale seasonally on an annual basis and not specifically stronger in any one season. This starkly differs from any traditional expectation of the jet stream heading south in autumn/winter in accordance with usual expectations, and heading northwards again for the Spring/Summer as the ITCZ shifts accordingly.

We must look at the arctic ice patterns, but this is a factor that most agree on anyway. But to my mind the changes in the natural cycles to negative (cooling), very much including the sun, which so happened to have occured in the last few years are playing a much larger part than perhaps is being believed in a lot of the mainstream scientific opinion

Your reference to the ITCZ has got me thinking, T: As the net loss of incident energy (due to the QS) must be greatest within the tropics, it ought to follow, that ITCZ's northward and southward limits would sink towards the equator, somewhat?? Are there any data available that might so much as suggest this to be the case? Could such an effect further contribute to PFJ meanders?

Edited March 24, 2013 by Rybris Ponce

[Paul]

This thread is too often moving away from the original topic - the title is: "Are we about to enter another mini ice-age",

We have a dedicated area for wider discussion on the climate, agw and all the associated subjects around it, in which it would be great to see more of you getting involved

http://forum.netweat...nd-environment/

[Tamara]

Cheers Tamara Road (Tamara, TR?)!

Experience and reality can be two very different things when it comes to the weather. The last image I included in my previous post shows the areas where the atmospheric thickness values (which can be a sign of jet stream ridging, but also heating) have been increasing between during 2000 and 2010 period, relative to the 79-99 average. The areas with the white asterisks symbols are statistically significant changes.

So while the jet stream changes may be felt more clearly in different seasons, the actual strongest changes relative to normal, have been in Autumn. It probably feels like one of the biggest changes for us has been summer, but that's partly due to us having a trough over us in recent years while Greenland has hogged the high pressure and warmth!

Perhaps a new study, taking into account the years since 2010 would show a larger change in Summer and Spring now also. Could be a netweather project!?

Anywho, I do believe that the -ve PDO, low solar and -ve ENSO period have been playing havoc with the jet stream too. But like anything in our weather, teasing out the mechanisms and even worse, trying to understand them can be incredibly difficult.

Hopefully tomorrow I might find time to give a more in-depth reply, but I've my last week of lectures coming up and numerous assignments to hand in, so I can't be sure!

Here's the image I mentioned.

And the paper it's from

http://marine.rutger...L051000_pub.pdf

I don't think any clarification is required about how I am addressed as much as any other member . My name is my name.. Its far too early to extrapolate anything from those images, bearing in mind the changes I mentioned have occured within the last few years. Much more time is required.

Edited March 24, 2013 by Tamara Road

[10 Days Away]

I remember as a kid in the 1970's borrowing a book from the library 'The Weather Machine' by Nigel Calder.1974.

He was an advocate of a mini ice age occurring within the next few decades. Although I didn't understand much of the technical stuff he certainly increased my interest in cold, snowy weather.

[Tamara]

Your reference to the ITCZ has got thinking, T: As the net loss of incident energy (due to the QS) must be greatest within the tropics, it ought to follow, that ITCZ's northward and southward limits would sink towards the equator, somewhat?? Are there any data available that might so much as suggest this to be the case? Could such an effect further contribute to PFJ meanders?

That is a very good question indeed - and one I don't have any answer to. Its all part of the melting pot of this very good discussion

[Midlands Ice Age]

That is exactly as it was in the period known as the LIA - unpredictability was one of the main problems facing the farmers in the affected regions. It's a mistake to imagine it was uninterrupted cold; drought was interchangeable with deluge, just depended on situation of trough and ridge.

I do not often post in these threads, but ..... (so please be gentle)

Looking at the above chart two things stand out to me during the 1650 to 1740 period --

1) The extreme incidence of above average autumn temperature figures

2) The increased frequency of below average temperature winter figures

The other 2 seasons seem to be about average by comparison.

Could this be an omen for what we are moving into?

What caused this effect during the Little Ice Age period? The sun was certainly very 'weak' during this period with regard to sunspots. What was happening in the Arctic at that time seems to me to be a vital part of the equation according to the BFTV

view of the climate. Does anyone have the real figures?

It could be that the next 40 years will provide the answer.

Midlands Ice Age

[jethro]

I do not often post in these threads, but ..... (so please be gentle)

Looking at the above chart two things stand out to me during the 1650 to 1740 period --

1) The extreme incidence of above average autumn temperature figures

2) The increased frequency of below average temperature winter figures

The other 2 seasons seem to be about average by comparison.

Could this be an omen for what we are moving into?

What caused this effect during the Little Ice Age period? The sun was certainly very 'weak' during this period with regard to sunspots. What was happening in the Arctic at that time seems to me to be a vital part of the equation according to the BFTV

view of the climate. Does anyone have the real figures?

It could be that the next 40 years will provide the answer.

Midlands Ice Age

What real figures are you looking for?

If it's Arctic ice then I'm afraid the only documentation comes from things like ship's logs, so not really comparable to today's measurements, they really only document ice extent/shipping routes/date of first or last safe passage etc. There is some proxy data too, but again, no where near as accurate as today - all that can really be gleaned is an overall, average idea of ice conditions during both the Medieval Warm Period and the Little Ice Age. The figures for sunspots are well documented, if you go back to I think page 3 or 4 of the thread, you'll find some links.

[Cheshire Freeze]

I have been thinking for some time now that we are experiencing the first throes or will very soon experience initiation of a large scale climatic shift. We've seen some remarkable synoptics all over the world in the past 5 or 6 years and to me it's no coincidence that this is happening at the very time the sun has decided to go into hibernation.

I've actually done some research into the solar side of proceedings and there is a clear positive correlation between sunspot numbers etc on the weather 'on the ground' at troposheric level.

I personally remain unconvinced that the foundations for a new Maunder type period are laid from the top down? I.e I can see no reason why cooling (anomolously) cannot start in the mid latitudes. Bigger ice/snow build up on the Alps, Urals etc after a while this snow compresses and accumulates further due to less summer melt......this is exactly the mechanism for glacier formation. In fact I'd say that it's more than plausible that there is a risk of positive feedback loop being triggered whereby blocking patterns perpetuate their own cyclic nature.

I don't see it as a coincidence that Europe (more especially NW Europe) may be more prone to regional cooling. We're probably situated in one of the more sensitive areas of earth to any imminent climatic changes due to our neccessity of NAD to keep us artificially warm during the winter months,for example. Hence as soon as we see an uprise in high latitude blocking the effects are possibly more marked. Also, I've seen a few comments in the vain of 'you can't extrpolate any cooling in one region to the whole of the hemisphere etc'. Well that's fundamentally wrong because from a holistic perspective having one region of the earth experiencing a major climatic shift will undoubtedly have rammifications for other areas; even if they're not initially affected (imagine a domino effect).

If we are infact to see a Maunder type period in terms of solar activity, I think the plunge into a colder scenario for Europe will be stark and swift and it's something we're going to have to get used to and adapt to. The mean length of the growing season will possibly be much reduced and that will have a knock on effect in terms of food & provisions prices.

I also don't buy fully into this 'raised baseline' in terms of temperatures. As far as I'm concerned, the further we've risen, the harder we'll fall.

Edited March 25, 2013 by CreweCold

[BlueSkies_do_I_see]

I think something is up, we've had some real crazy weather over the past 10 years, off the top of my head.

2003: Hottest temperature recorded, severe heatwaves, very dry

2005-2006 winter: Coldest for a decade I believe

Summer 2006: Record breaking heat, hottest month ever for many, hottest temperature ever for many, dry

April 2007: Hottest and driest April ever for many

Summer 2007: One of the wettest ever, mass flooding

Summer 2008: One of the wettest ever, mass flooding

February 2009: Most severe cold and snowy spell or some time

Summer 2009: Yet another poor summer

November 2009: One of the wettest months ever, mass flooding

Winter 2009-2010: One of the coldest winters ever, coldest ever in Scotland

Summer 2010: Poor summer for many again.

November/December 2010: Coldest, driest December ever for many, record breaking cold and snow

2011: Wettest year ever in Scotland, one of the driest ever for central/SE parts, drought

Early 2012: Severe drought in many places, hosepipe bans, the driest 18month period for many since 1975-1976

March 2012: Warmest and driest March ever for many, temperature records broken

April 2012: One of the wettest Aprils ever, mass flooding

Summer 2012: Wettest summer ever for many, mass flooding

2012: Wettest year ever for many

Later 2012: Continuing severe flooding, one of the wettest Decembers ever

March 2013: One of the coldest Marches ever, record breaking snowfalls

Probably forgot some too. That's a lot of extremes and record breaking weather in a short time, especially since 2007.

A combination of a weaker more meandering jet stream due to reduced temperature contrast between the Poles, low solar activity, loss of Arctic sea ice, sea currents being disrupted most likely. A little Ice Age, well maybe, there are similarities. If it happened before not so long ago it can happen again.

[BlueSkies_do_I_see]

Bobby, this is a summary of what I wanted to collate but have not been able to.

When you list it like that, it is amazing how much extreme weather we have had.

I very much appreciate you taking the time to write it.

[Iceberg]

So did 2012 see A CET below normal ? Let alone towards mini ice age standards

Did 2011 see a CET below normal ? Again Let alone towards mini ice age standards

Now apart from a bit of cold weather is there any evidence we are entering a mini ice age ?

[syed2878]

i wouldnt say we heading into a mini ice age but i beleave that we are entaring a faze of below avrage winters and cooler summers, with mild winter throne in here and there. Same with our summers we may get a below avrage and a verry wet summer throne about. I also beleave our climate is also on root to change, how ever i never bought or buy into man made glowble warming bullonions. I wander what spin the gw police r going to put out to spread their lyes to the tax paying publick.

[Iceberg]

That is exactly as it was in the period known as the LIA - unpredictability was one of the main problems facing the farmers in the affected regions. It's a mistake to imagine it was uninterrupted cold; drought was interchangeable with deluge, just depended on situation of trough and ridge.

As always with these things you need to check out the anomaly reference period why a single year and why 1950 ? If you use a climate average of 1960-1990 ot 1970-2000 you will get quite a different chart wrt anomalies.

[Iceberg]

i wouldnt say we heading into a mini ice age but i beleave that we are entaring a faze of below avrage winters and cooler summers, with mild winter throne in here and there. Same with our summers we may get a below avrage and a verry wet summer throne about. I also beleave our climate is also on root to change, how ever i never bought or buy into man made glowble warming bullonions. I wander what spin the gw police r going to put out to spread their lyes to the tax paying publick.

The first two sentences i agree with. Again though this isnt anything to do with global anything as people are looking at local temperatures and rainfall for our small area and wondering whether this is a prelude to what occured during the LIA.

For the last few years we have averaged something similar to the 1960's and the 1960-1990 CET avg, there are possible reasons for this, but scant evidence its a prelude to anything resembling the very troublesome climate of the LIA.

[VillagePlank]

It wouldn't surprise the vast majority of people that there is a statistical measure of how far the CET figures are spread out - ie how far temperatures are observed to lie from the average of the data. This is known as a dataset's variance. Of course, knowing this we can test the assertion that, given climate change, and subsequently, higher CET temperatures, we are expecting more extreme temperature than what we've previously had.

So, without too much ado, here is the annual averages of the CET series since 1772,

And, here, is the running 30 year variance of the CET series,

So, within recent memory, the extremes of temperature are on the increase, but overall? Well, let's just say it's been worse. Am I correct in suggesting that CO2 output was rather low around the middle of the 19th century? I thought, by eye, that there looks to be some correlation between colder temperatures and 30 year variance seeing as the highest variance seems associated with the LIA. So, I tested the idea,

Leaving the only possible conclusion that 30 year variance has absolutely no correlation with annual CET averages, and it strongly points to another (external) factor to the data series, such as Arctic amplification, PJS modification, etc etc. But whilst an increase in temperature extremes did occur prior or during the LIA this is purely coincidental, rather than a statement of fact. That the CET is warming, and the variance is also increasing about the same time, is also purely coincidental, rather than a statement of fact. There is an exceptional weak signal that higher variances are associated with colder annual CETs.

Increases in extremes is not associated with CET annual temperatures either warm or cold, and the recent rise in extremes is nothing really compared to what's come before. All in all, rather unremarkable, and taking these ideas on their own, there is no evidence of an impending ice age, nor a boiling planet.

Edited: to change comments about weather to refer to temperature, instead.

Edited March 25, 2013 by Boar Wrinklestorm

[VillagePlank]

... and whilst we are at it ....

Climate change does happen and has always occured. So what does it look like if we compare each annual CET temperature to the previous 30 years? This factors in the notion that climate is changing constantly, rather than climate changes in respect to a fixed, arbitary (as far as I can see) 30 year period.

Here it is,

Whilst the trend line is not a good fit (low R² score) this is probably down to a huge amount of noise in the chart, and I would certainly subscribe to that upward trend of, wait for it, wait for it, 0.05^oC.yr - with the rather more worrying decadel figure of 0.5^oC/decade (about half the normal prediction) So, it is true to say that the CET is warming with respect to each years previous 30 years. Significant? I'm not so sure.

Impending ice-age? It's not showing in any of the data I've looked at.

Edited March 25, 2013 by Boar Wrinklestorm

[jethro]

So did 2012 see A CET below normal ? Let alone towards mini ice age standards

Did 2011 see a CET below normal ? Again Let alone towards mini ice age standards

Now apart from a bit of cold weather is there any evidence we are entering a mini ice age ?

No one is suggesting we're currently in a mini ice age, the title of the thread is Are we about to enter? Not have we or when did we?

The general consensus of Solar Physicists is that the Sun is looking increasingly likely to go into a prolonged, dormant phase. These deep minimum phases in the past have resulted in unusual weather in the NH, more extremes of weather, including much colder winters here and NW Europe.

Looking at the history of these deep minima phases, it's wrong for people to assume it just means cold weather, it doesn't. There were runs of hot summers, dry years, wet years and yes, cold years. The predominant impression which can be gleaned from the old weather details is that weather appeared to get stuck in patterns, so if it became wet, it stayed wet for longer than usual. Ditto for dry, hot, cold etc.

The Little Ice Age was caused by a sleeping Sun, that really isn't in any doubt, there is plenty of evidence to support this. Evidence is mounting that we're entering into another period of low/extremely low Solar activity. So really, the only questions or doubts are what is likely to happen to our weather, when is it likely to happen given a Solar lag period (is there one when it comes to UV levels, if so how long), has it already caused a change and will the likely impact be mitigated or amplified by man-made climate change.

The mechanism which is thought to be responsible for changing the weather are UV levels, the apparent impact upon weather felt upon the ground is a tendency for blocking patterns to emerge, so our weather gets stuck in a rut. Looking at recent times, that appears to be exactly what is happening. Coincidence? Possibly, but an unlikely one.

[VillagePlank]

I suppose it's possible that increases in temperature lead to increases in precipitation?

Sorry, no evidence in the CET/UKP record to support that idea, and once again, lower temperatures are weakly associated with greater variance, and, also, we've seen greater variance in precipitation in England and Wales in the past, rather than recently. By quite some way, actually.

So next time someone says, it's raining hard because it's warmer , *cough*, tell 'em where to shove it. (actually, it might well be raining because the planet is warmer (ie external factors to the UK climate system) but it isn't because the CET climate is warmer - maybe a distinction there for the die-hards)

Edited March 25, 2013 by Boar Wrinklestorm

[jethro]

I suppose it's possible that increases in temperature lead to increases in precipitation?

Sorry, no evidence in the CET/UKP record to support that, and once again, lower temperatures are weakly associated with greater variance.

Surely if you're studying with reference to the possibility of a new LIA, you'd have to go back to the time of the last one to make comparisons?

[Iceberg]

The problem with discussing solar is that its the biggest component of the more combative climate change discussion and generally results in looping arguements, currently their is no evidence of a) CET declining to anything like the mini ice age levels, nor to a CET that led to the mini ice age levels and Solar irradiance (SI) is nowhere near the levels scene during the LI (it is SI which essentially is the measurement of the energy of the photons etc(very simply)). sunspots are something else and something very contraversial.

http://lasp.colorado...orical_tsi.html

Last point we keep hearing about weaker Polar jets etc, but i have never seen any evidence for this, there is a general northern hemisphere blocking index how does this compare over the last 2-5-10 years ?

[VillagePlank]

Surely if you're studying with reference to the possibility of a new LIA, you'd have to go back to the time of the last one to make comparisons?

No measurement record, unfortunately, so can only do a correlation with what is available.

[Iceberg]

I suppose it's possible that increases in temperature lead to increases in precipitation?

Sorry, no evidence in the CET/UKP record to support that idea, and once again, lower temperatures are weakly associated with greater variance, and, also, we've seen greater variance in precipitation in England and Wales in the past, rather than recently. By quite some way, actually.

So next time someone says, it's raining hard because it's warmer , *cough*, tell 'em where to shove it. (actually, it might well be raining because the planet is warmer (ie external factors to the UK climate system) but it isn't because the CET climate is warmer - maybe a distinction there for the die-hards)

Surely rainfall = cloud which locally will surpress temperatures, the very warm years tend to warm because they have long hot summers i.e HP over the top of us or drawing in southerly plumes, which generally dont give high CET (precipitations) as they are local.

[Gray-Wolf]

Just a little quizzical urhm? Ships logs and the Arctic. even as late as the late 30's folk could not get into Barrentsz due to the massive ice there? Whalers could not travel into the Arctic by the NE tip of Greenland due to sea and fast ice of giant proportions.

How can these not show a marked difference from 'historic ships data' (folk who earned a living off the sea and so needed to know when and where to travel). Ice islands mistaken for 'islands' with 'beaches' are something you will not see in the basin these days!

The logs show an Arctic full of paleocryistic ice of giant proportions not FY ice of 2m+ , flat and featureless allowing meltwater lakes to flood it during late April May?

Surely the lack of 2m temps and humidity plots looks a bit of a 'pedants ask' in the light of the mammoth physical changes obvious there?