Nope, but we haven't quite hit the coldest stretch yet.
24F a couple weeks ago. Last winter we hit 17F a few nights in a row...which I always enjoy.


Josh

A lot of places have had trouble getting as cold as they did back in the 1980s and 1970s. My parents got below zero 14 days in the 1980s... but haven't been below zero since 1994 (the only year in the 1990s when they were below zero, for a total of 3 days). The old map was 6B, they're now 7A.

Poaky, most of the radical changes in micro climates have to be because of random variation or urban/suburban heat islands.

The effects of global warming are more subtle and difficult to see in a yard by yard basis.

Example, if in the environment of 100 years ago the cold temp last night would have been 8degrees would I really notice it if the low was 10? Not really. Most of my plants wouldnt notice either.

Now 100 years ago there was a house and a barn on the land where a subdivision a dozen roads and four of our 1 acre lots are. No doubt there were fewer protected areas near heated structures to hide tender plants and less concrete to soak up the sun during the days.

I just wondered if these new zone maps were so far reliable to what people were getting lately ( past few years) I know when I was a kid in the 70's and 80's there were some below zero temps,but as a kid I didn't care. May have liked the snow days!No school!I am gonna look up the record low for my area.But it's been a while since we got below zero here also.Arktrees I'm shocked ( dispite the valley thing) that you got -3 my geography is bad but aren't you pretty far south? I guess it depends on how the air flows? And as mentioned winter is not even officially here yet.Arbor day has me at zone 6/7,but I will buy zone 6 hardy plants, except for that zone 7 fern out there that lived through last year.Arktrees you are in Arkansas right? I just assumed, sorry.Toronado I know a bit about the microclimate thing, but I meant just a general observation. In other words if I go by what the news says the temp will be tonight I can beleive it's close to what mine is, or I can check the thermometer on the porch and they're within a couple degrees of each other. Now if it's supposed to go below 0 I'll check the thermometer.I use the weather channel too, as long as it's not close to zero.I wonder how the wind - chill factor effects plants? If it's a wind-chill factor of 10 below does the plant get freeze burned like it's 10 below? I guess unless you've learned from experience how would one of us know that one.

Rural stations haven't reported warming in +130 years in parts of California.
As Toronado mentioned, the Urban Heat Island effect can easily be manipulated...
in particular, place a sensor in a parking lot, on a hot building, or above an air-conditioner
(which often shows temps in the immediate proximity to be higher by 5 degrees F or so).

I've been keeping a Weather Journal for a while now, and I advise others to do the same.
I noticed that each year the wind would appear at certain times and many folks around me
acted surprised...a lot of "It's NEVER been this windy before!" (Same with the cold, the
snow, the rain, et cetera). However, I contended that it was merely their memory failing them,
rather than the Sky Falling, and thought to myself, Yeah this is the windy time of year.

So I set out to document when cold temps, rain, and wind were likely to occur.
Lo and behold! I've been able to predict the rains in August and the snows in February
in my area, simply by being observant of past trends.


Josh

As for applying hardiness zone maps to all this...

The hardiness zone maps aren't meant to show the lowest possible temperature an area can experience or even indicate what temperature variations are possible. The USDA map and similar maps are based only on the average annual minimum temperatures experienced in a certain period of time (in which the measurements were made). During that time about half of the years would have had a lower annual minimum temperature and half of the years would have had a higher annual minimum temperature. I don't think we can say much one way or another by relating hardiness zones to a current monthly low.

The newer map (I'm guessing this reference is to the Arborday Hardiness Map) is more correct for most areas than the older USDA map. It's not because of the way the map was produced, but because of the newer data that was used. Like it's older cousin, it also seems to loose it's relevance as time goes on.

A newer version of the USDA map has been in the works for a very very long period of time. It's supposedly been on the verge of being released for many years, but keeps being delayed as new ideas are considered (reasons vary depending on who you ask). Some have recommended that the new map be dynamic and attempt to stay current, but this opens up a whole new can of worms to consider.

"Rural stations haven't reported warming in +130 years in parts of California."

Why California? Rural station across the US, on average, have reported a clear warming trend over the past century. Data from a few urban stations may have been compromised over the past few decades, but this is the exception and great care is usually taken so that this doesn't occur. Also the effects of urban heat islands on data is generally taken into account when scientific observations are made about more general climate trends. The localized urban heat island effect is used more commonly to support extremist viewpoints about the lack of climate change rather than it's reality. Climatology surely has a long way to go, but some falsely assume that we're still back in the eighteenth century with little experience about how our weather instruments work.

I found a chart on the NOAA website with the record low temp for each day of the year and when it was set.

It seems while zone 6 St Louis has only been below 0 F perhaps two days since 1999 we have hit the negative teens almost every decade before. I will wait another decade to say this is a trend because in 1974 it was easier to set a record which was only kept since 1888 than now because now we have to beat any 1970s records also.

Here is a link that might be useful: NOAA record temps

I choose California because I have a vested interest as one of her natives.

There are major problems with the reporting and accounting for the measurements taken.
Data are usually adjusted rather than corrected - adjusted across 1200 miles in some cases.

Now that the data are being reviewed by folks other than the AGW extremists,
we're finally learning where significant errors lie. Things look awfully
different when there's someone looking over the shoulder to corroborate the data.
Gone are the days of blindly swallowing the Sky is Falling mantra.

This is the type of open, unbiased, peer-reviewed science that should have been conducted
in the first place. Instead, we rushed to implement policy based on hasty, short-sighted,
and oft-manipulated data.


Josh

"Gone are the days of blindly swallowing the Sky is Falling mantra."

I wouldn't say that AT ALL! Seems to me like political skewing of data and analysis is more alive today than ever before, with no end in clear site. Many are not the slightest bit interested in reality, but only the spin they can put on results to back up their view of how they would like things to be. Even many members of this forum want to use the Trees Forum for political gain. That's why I think we should just agree to disagree here (at least in the Trees Forum) and try to limit the discussion to how climate will effect our gardens. Sure, the subject of global warming will come up, but we shouldn't have to discuss the sky falling, or one of the many ridiculous ideas on the other extreme. Extremes are often wrong and almost never based on reason, science, or even common sense. One extreme or other could turn out to be right, in the long run, but our discussing it here in this forum is not likely to change that. I think we should try harder to stick to trees.

greenman28,

Were Sarah Palin's park rangers lying to me about Exit Glacier retreating?

How about the Portage glacier folks?

The debate seems to be if the cause is man made or not. Interesting debate it is. We KNOW the effect of greenhouse gasses on heat retention in simple environments. We KNOW the earth is considerably more complicated, for example we KNOW variations in the sun's output occur in cycles. So we do not KNOW what our current cause of warming is.

So being the conservative stick in the mud with a child that I am I support limiting our possible effect on the environment but not going off the deep end.

So Toronado3800 et al., what have you guys planted lately that you wouldn't have planted if the weather in your area was more like it was a couple of decades ago? Or, if you live in an area with a more stable climate, do you consider possible future climate variation (even just a short term change, like a two year drought, or an especially cold year) when choosing plants for your yard or garden?

Eh, Toronado?
I'm not sure why you've addressed those questions to me?
Did I somewhere say that glaciers aren't shrinking? (I've probably said something about
antarctic ice growing, but not in this Thread certainly).

I'm a conservative type who believes the climate is always changing....


Josh

So Josh, don't you have ANY thoughts on trees you'd like to share here in the Trees Forum?

...do you consider possible future climate variation (even just a short term change, like a two year drought, or an especially cold year) when choosing plants for your yard or garden? For instance, what hardiness zone are you in and what hardiness zone range do you seek in plants for your yard/garden?

Yes, indeed, Brandon!
First, I'm in a strange location in the foothills of the Sierra Nevada.
If I try to plant zone 8 trees, they die at some point during the Winter....
but if I plant zone 7 trees, they survive. To further confuse the matter,
my zip-code would say that I'm in zone 9 - but that zip-code zone-finder
won't replace dead trees for me, either.

My Summers are also dry. For a couple years I've been reducing my lawn,
in favor of mulched beds around conifers (with moisture-trapping native ferns
and such growing around them). I'm attempting a very efficient landscape that
requires minimal watering, as there could come a day when the water demands
to the south put a damper on my own usage (although water is ample up here).


Josh

That's weird being in zone 9 (according to the map) but having to stick with zone 7 plants. I have just the opposite here. I am officially (per USDA map) in zone 6, but our weather here has been right on the borderline of 7b/8a for a long time now. There are quite a few decent sized trees of various types doing well here that I don't think could have possibly made it back 25 years ago. I generally pick trees that will survive in zones 6 through 8. That way, I figure I'm about as safe as I can reasonably be. It wouldn't do any good to plant zone 9 trees with current temperatures, and trees that need cooler temps than are typical of zone 6 would probably just stress out with our current hot weather. The one big advantage I have at my farm is some pretty noticeable microclimates. I always take those into consideration when choosing where to plant things. I've got around 5 acres in a cooler than usual microclimate and about 7 or 8 in a warmer than usual microclimate. The rest is average to slightly cooler.

Moisture/rainfall have started being a big concern. Many of the last few years have been very dry around here. We've seen a number of drought related records. I'm fortunate to be in one of the wetter areas in the country, but I'm beginning to see what it's like to do without rain. At least we've not had it nearly as bad as the Atlanta area. I feel sorry for those folks. A lot of them have just given up on the idea of growing plants in their yards. I'm hoping that the shift we're seeing is only temporary. The weather patterns have shifted quite a bit and no one is sure what to expect. I hope the dry conditions turn out to be an anomaly, but I'm considering that more and more in my garden plans these days. One thing that may turn out to be useful for my garden is a large creek that runs along the back edge of the property. Even when everything else looks crispy around here, that creek has had quite a bit of water in it.

That's interesting...I have a creek (seasonal) that basically marks my back property line....
technically, my property includes the large oak on the other side of the creek, too, but that's only
evident on the actual property maps.

I attribute the microclimate to the geographic features and the elevation where I live.
Believe it or not, I've lost Ailanthus during cold Winters. And that's absurd. Most folks *wish*
their Ailanthus would freeze to death....meanwhile, I struggle to size them up in my chilly backyard.
I've switched to the much better Liquidambars instead.

I'm focused on planting trees that can free-range, without additional Summer water.
The Summer temperatures have dropped in the shady greenzones I've created.


Josh

Its my fault greenman28 is talking about the south pole. I baited him.

greenman28, you are referring to the Inhofe/Crichton remarks I take it in regards to the ice sheet growing?

We know that it is now basic knowledge that nighttime low temps are getting warmer. That is why the new maps are coming out.

{{gwi:286674}}

And its warming in winter in Europe as well:

These are all things we know. There is no need in civil discourse to "debate" known things.

We also know that recent, unprecedented changes are not uniform across the planet. It is wise to understand these recent and projected future changes for our area when making decisions about long-lived plants, as some places will get less water in a warming world, others will get more (albeit more episodically).

Those who refuse to admit basic physics works here on planet earth will not be able to adapt and will be left behind. In my view it is wise not to expend energy on those who refuse to listen; call it Dunning-Kruger Effect, knows not they know not, whatever. It is important to help transition to a warmer, more chaotic biosphere.

Dan

Josh,
The fact that you INSIST on trying to label people i.e. "reviewed by folks other than the AGW extremists", and other such things, shows that you know your argument is WEAK. The term used is 'poisoning the well" where you try to discredit the opponent by labeling them as some way undesirable, with the intend of then using that to label them are as lacking creditability. As for the reason you choose to use California, is it to present skewed data. For starers you say nothing of where those "rural stations" are located. If you actually presented data, I'm sure they are rural coastal California. Reason why, you got that nice hugh ocean just to the west that will buffer any changes in climate. Also the reason for you need for zone 7 plants is likely elevation if you are honest about it. Zip codes are VERY course and do nothing to take into account elevation. Locally I am about 1200', but that normal for the area, however less than a mile from me is 1700' elevation. The rule of thumb is 5.5 degree/1000' elevation. So 0.4*5.5= 2.2 degree cooler, and guess what. There have been times that there was accumulating snow on top of that hill, and very little accumulation here in the valley. Since you say you are in the foothills, I bet if you are honest you are at around 3000-3500'. So present real data, if you have any.

Poaky, yes I am in north Arkansas is a zone historically labeled as 6b. The new Arbor Day map has the line for 6b/7a at the north county line of the county I live in. So even for them I am borderline. My climate has actually been relatively stable outside of temperatures. I look at the forest around me, and there are sapling sugar maples in the understory, there are small hickories, oaks, red maple etc etc indicating that my local climate is still doing well for the time being. However there has been less snow recently. Part of that is due to sea surface patterns. Looking back at the local weather history and there were similar occurrences in approximately the same relative time to very active hurricane season (which are obviously heavily influenced by overall global pattern). So I'm not ready to radically change my habits on planting, however I do tend to make sure whatever I plant will be fine in Zone 7 as opposed to Zone 6b.

Arktrees

Arktrees, let's leave the politics out of this.

I apologize for using that line - Extremists - and for the "Sky Falling" remark
about folks locally who balk at the seasonal winds.

In regard to "extremist," I was responding in kind to the comment previous:
"extremist viewpoints about the lack of climate change rather than it's reality..."
and "some falsely assume that we're still back in the eighteenth century with
little experience about how our weather instruments work."

I figured, Hey, since we're using the "extremist" label now, and getting clever with the insults,
I might as well use it, too. So why do you single me out, sir?

Secondly, you just impugned my honesty with this line:
"Also the reason for you need for zone 7 plants is likely elevation if you are honest about it."

The implication is that I'm dishonest. In addition, you missed what I wrote most recently:
"I attribute the microclimate to the geographic features and the elevation where I live."

Moreover, we've moved on to discussing trees. You come late to the table to fan the flames.


Josh

Josh,
Actually you avoid the questions and points I posed, and I did not "come late". I either directly started, or sparked these discussions.

Present data please.

Arktrees

I cannot respond to your latest comments without getting into the politics.
Sorry, the politics angle is over with this discussion, and I won't be baited.
I don't want to be Gently Reminded or given a vacation from GardenWeb.

Moreover, you avoid the fact that I mentioned, explicity, my elevation as a factor
in my zone calculation.

Again, I don't wish to be kicked from these Fora.
Please respect that.


Josh

tornado, I must be an idot but I can't find the same Milwaukee histroic data that you found for St. Louis.

I tried backing up on the link. Can you post the top level link?

Josh,
Missed the point on elevation, but still don't know what your specifics of elevation are. The discussion can be apolitical by using data. To be sure, when the names start flying I will usually get much more pointed in my arguments. Reason is that it is a method of defeating the labeling technique. For the honesty remark, that was not an implication that you were dishonest, but more of if we know the full story kinda of thing. Poor choice of words. BTW, kudos for trying to minimize your use of water, and increasing your "greenspace" and reducing your lawn size. Responsible action is always pleasant to hear about.

This is a general statement not directed to Josh, as I do not believe that Josh is a part of this. Be careful of people presenting arguments that are paid to "muddy the water" so to speak. They are employed in the industry of doubt. Doubt is their product. They are the one most likely to present "data" without giving you the source, nor background, or old far outdated articles. They are also the most likely to start throwing labels, rather than just keeping to the science. I don't believe that has happened in our discussions, but they are rampant in the media. Many large corporations have been caught repeatedly doing just this to influence public opinion. The tobacco industry engaged in this for decades. Just a word of caution for all readers.

Arktrees

I for one don't feel like we need these cautions nearly as much as we "need" to talk less about politics and more about trees. I don't think we need more data that supposedly backs a certain position. Sure, ample data exist on the subject for some conclusions, but what's posted here is not likely sufficient to change the minds of even those sitting right on the fence. Josh and I were talking trees, then the agitators moved back in.

BTW, anyone that actually wants to talk about the politics of this would probably feel right at home in the Hot Topics Forum. They have debates about this quite often and people there would surely be interesting in hearing your points and debating you.

I started this thread which is not directly about trees. I was thinking about if I can trust the new zone maps for planting things in zone 6 that may have been zone 7/8 in the past or do I have to worry about a blast from the past? And there isn't much tree related going on for the most part. The mummified forest thing shows that the climate was changing before we started pollution of our air etc.

The mummified forest thing shows that the climate was changing before we started pollution of our air etc.

Erroneous conclusions from false premises aside, the zone jump is best 1/2 - 1 zone, depending upon the time scale goals.

HTH.

Dan

Poaky1, I can't see why saying the climate has changed sometime back in history is germane to any of the above conversation or to the topic of the thread (that is, hardiness zone maps, global warming, or even what plants/trees we should grow). We all know that it has, and that it has a number of times. This seems more like a distraction or just a complete misunderstanding of the issues.

I think I addressed your original topic concerns earlier with my post about the Arborday map, but, if not, maybe you could restate your concerns/questions.
______________________________________

Dan, what do time scale goals have to do with zone jumps (in this case)?

I hope I don't regret asking, but I am curious.

I forgot I posted about the mummified forest on the thread that Arktrees started. In general it was about a mummified forest from the past, I would say very long ago where the plants were covered by a glacier and the ice is receding now. It was on the yahoo home page 2 or 3 days ago. I used to be zone 5 and now zone 6 and some places 6/7.I don't know the reliability of the news source,but I don't see any reason for it to be lied about.Everyone believes what a source of one kind or another tells them.If we could all see 100% proof there would be no arguments, which would be great for all the hot topic subjects.I will think better before asking a question on here, at least in terms of getting people worked up.If the warming continues it will be slow and we'll all be dead by the time the north is tropical, except maybe for the kid that was on here a while ago.poaky1

brandon7,
I'm not Dan, nor do I speak for him, but I took it to mean time scales where we normally live at a location. i.e 30 years. But if you are talking on scales of 100+ years, then "zones" may be more affected and even less certainty of exact results. Changes yes, but to what degree?

Dan please correct me if I misinterpreted.

Arktrees

Poaky, I think the real problem with this topic is that some of us are really interested in the implications of the changes we see in our weather, but others see any mention of climate as a trigger to react emotionally and respond as if they are for some reason under attack. It really is a shame, because the topic deserves discussion. We'll never solve the debates surrounding global warming here on GW, but we might be able to more effectively deal with the changes in our climate, that impact our gardens/plants/trees, if we were able to discuss the topic without all the emotion. I'm about to the point that I think many are not able to do that, but it sure would be nice. One thing for sure is that it would take everyone doing their part to keep the conversation on track.

It's hard to predict people. The other day I mentioned a hybrid plant, and the lady I talked with basically told me that hybrids were an abomination and started quoting me bible verses about why hybrid plants were not part of God's plan. I barely escaped without getting burned on the stake. I think she believes that only Satanists grow hybrids. LOL

In reference to trees near the artic circle - a contributor here is continental drift. I have a difficult time figuring out which part of Pangea turned into what today. Things have moved a bit though. Even if the latitude (did I get the right one?) of a land mass hasn't changed ocean currents may have been disrupted to affect the surface temps one way or another.

I watched a program that mentioned that New York has basically been in the same location
from Rodinia to Pangaea to today...through all the forming and diverging of the supercontinents.
I am very fascinated with Earth's ancient history.


Josh

In reference to trees near the artic circle - a contributor here is continental drift.

This would be relevant for fossilized trees, but not mummified.

Dan, what do time scale goals have to do with zone jumps (in this case)?

If your goal is to have the appropriate zone at the tree's maturity, then significant zone jumps are an appropriate consideration. If your goal is to have the appropriate zone in a human generation, then significant jumps are likely not a factor. The two time scales are different (~100 vs ~20).

But this is all based on the presumption that one or more large ecosystems won't flip and change state. If that happens, all bets are off.

Dan

I think the weather in St Louis has been stable for trees over the last century.

Is there any evidence of temperatures in North America being significantly different for trees since the French or the Native Americans "owned" St Louis several hundred years back.

Perhaps Europe has better records.

Lets say something radical like the earth will warm by whatever reason by an average of 8 degrees over the next hundred years. We are in an average location and rain patterns don't change. This simply will not affect my trees that much. Bur oak will still grow here. Southern Magnolia might do as well here as they do in Memphis?

My theory is temp differences make a bigger difference to those near the Artic and on small Pacific islands.

Yes, for many areas in the US, average temperatures and weather patterns have changed considerably over the last century. Actually most areas have experienced what I would call significant change in the past two to three decades.

It's not practically possible for the earth to warm by 8 degrees and rain patterns not to change, but, if it did happen, massive extinction would follow.

Warming by 8 degrees doesn't just make the air warmer with no other changes. It changes winds, rain, droughts by changing distribution of where water is, isn't, where ice is, and isn't, and the gradient between pole and equator. You are likely to see changes in rainfall or distribution of rainfall. It may be wetter, or drier, but you are almost certain to see changes.

Arktrees

But if St. Louis was JUST eight degrees warmer I would be almost zone 7. Like Memphis, Sikeston MO maybe?

I contend that alone will not kill many trees in my yard if any. The warmth may allow changes in the natural areas around me.

Brandon, perhaps I just don't see it. Where is the weather the most different? Las Vegas is still a desert. Seattle still misty.

Using Vegas for an example I know Lake Meade is lower than they hope and everyone pretends it is because of record droughts not human use. We are talking 1083 ft as opposed to the 1950's low of 1085 though.

Brandon our posts must have been at around the same time, I just read your question of me sorta confusing the issues. The point of bringing the glacier trees was just me wondering that if nobody was polluting the air causing the warming effect all those years ago, that the warming could possibly be something that has nothing to do with human related climate change.Because this has happened before when people weren't enhabiting earth. It was not my original question because you did answer that. I got caught up in all the debating and went from my original question to thinking about the warming being our fault or gonna happen anyway.Toronado brought up that it's possibly human related and that's where my topic switched. Not anything against Toronado, but him stating that got me wondering if we're the cause why has this mummy tree thing happened before we were on earth? There is alot of science put into the human pollution, man caused, warming theory, and I even sorta think it's true but if that's true, why was there climate change before humans?I got fossil and mummyfied mixed up. I hope I've explained my leading off in another direction good enough.And the zone maps (as far as I thought) were very rigidly based on a zones lowest temp being the coldest each plant will survive.In other words I buy a Bur oak which is (guessing) zone 3 -8. I based on that map can be sure that tree is hardy to what zone 3 is on the chart, being -30 or whatever zone 3 is. That is what I,ve always thought. Well, according to that map the Live oak Q.Virginiana should not have died because last year our lowest temp was 12F and if the tree was labeled zone 7 that is 10 - 0 F if I'm not misstaken. (Even though My tree was labeled zone 6, but was from a Florida store).By the way that's something else about the hybrid tree thing.They must have been an extremist.It would be like saying that a mutt is a satanists dog.Sorry this is so long.

Poaky there are all kinds of causes for climate change. I don't mean to be confusing but it IS a complicated system.

Natural events like the 1815 Tambora eruption coupled with a low solor output year caused the Year Without Summer.

Other things like meteor impacts, wobbles in the orbit and natural cycles cause ice ages and the warm periods in between.

If we were headed into another immediate ice age and Norway wanted to prevent it they could pump out tons of gasses which hold heat better than the Nitrogen and Oxygen heavy atmosphere in some attempt to change it. Like a dangerous experiment from a science fiction show.

Here is a little picture of land masses in the late cretaceous and the spread of Metasequoia
{{gwi:498945}}

Crude animation of continental drift. Continental drift causes individual areas to differ in temperature due to changes in prevalent air and water currents

Modern ocean currents. If you live in southern Alaska (a place near a red current) you get a bump in your temperature. Being near an ocean in general moderates your temperature. England is warmer than Minnesota or central Canada because of that and the red currents.
{{gwi:498946}}

Thanks for taking the time to post this info.I sheepishly ask, have fossils of Metasequoia glypsoboidies ( glypso-something) been found in the Northwest?I may have misundwerstood that globe in black and white.The link that you gave was interesting, it looks like many factors are involved in weather. I've heard about how the ocean moderates temps, that's why Philly can grow things I can't.And of course England not being overly cold. I thought they were alot warmer than they are, tilasking someone about it, I saw palm trees in a couple places when I went there before. Not a lot of them but a few.They were probably in a micro-climate though.But anyway as far as my original question goes, most people have climate that fits the hardiness zone maps except for Greenman and that's cause of the mountain he's close to. And Arktrees in the valley came close to the - 10 limit of zone 6 .That's so far for this year.One thing I can't help thinking about is in that year of no summer and Asia having the crop failures along with everyone else, those bomb proof Ginkgo trees survived that also. So did alot of trees I guess.One thing I know when climate change comes up again....and it will. I'm staying out of it!

Poaky, millions of years ago Metasequoia apparently did grow on the west coast.

I'm reading what is available freely of the book listed below. It is where I copied the map from. If I'm keeping track right between 50 million up to 800,000 years ago the species could be found on the west coast.

Apparently different genus of Metasequoia, Occidentalis, Milleri and Foxii existed. I myself am unclear of the differences between Metasequoia glyptostroboides and the rest but assume it is minimal because the scientists themselves were having trouble determinging where to draw the lines.

Here is a link that might be useful: Check out page 16 or so of the book

The Year Without A Summer was the culmination of several years (1812-1815) of volcanic activity, if I recall.
It was a terrible time to be growing crops...late snows and frosts deep into the Summer.

Periods of Global Winter have been a fascination of mine for the past decade.
I'm impressed with how tough our ancestors were...and yet amazed at how narrowly they survived.
Massive extinctions and population bottle-necks tend to correspond with disasters, followed
by bleak and bitter cold/snow.


Josh

I'm impressed with how tough our ancestors were...and yet amazed at how narrowly they survived.

The agrarian civilizations of Homo sapiens have existed only within a very narrow temperature range:

{{gwi:498947}}
Note the year produced. Please deniers, no statements of the refudiation of the Hockey Stick, please. TIA.

Note that there is a total range of ~2úC. Our current hopes at trying to get human societies together to somehow in an unprecedented way manage themselves say a 2úC warming will avert major societal change. That is a condition with which we are not familiar. There will soon be no precedent.

Dan

I was thinking further back, Dan.
200,000 - 20,000 b.c. Mount Toba in particular.
Thanks for the graph, by the way!
That'll come in handy.


Josh

"Brandon our posts..."

Sorry, but I don't think it's appropriate for me to get into the cause of global warming here, and I'm just not going to go there. I will say that most climate scientist are fairly certain about many aspects of the subject, and I think a few people deliberately try to obscure the truth (for various reasons), on both sides.

You guys can discuss to your hearts content, I sorta wanted the "weather observations for dummies" version and got all you more educated, or well read people fighting and the graphs and stuff are things I can make sense of partially but not enough to make total sense.It's kinda like understanding Spanish some words you can get the gist of cause they are close to english and the majority doesn't get through.poaky