Global warming: Has your plant climate zone changed?

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Is it just here or has your climate zone also shifted in the past decade as a result of global warming?  For the past seven years, mine has.  I am supposed  to be on the border of USDA zone 8b and 9a, but I have just had seven consecutive years of zone 9b winters, including at least one zone 10a winter too.  I don't know whether this will be a permanent change, but I am taking risks by making zone 9b plantings now.  2010 was a zone 8b winter here, so I am definitely taking a risk based on the assumption that zone 8b is gone forever.  

Unfortunately, most of you outside the United States will not be familiar with USDA cold-hardiness zones (zones 1-13), but I have to refer to something as a standard for this discussion.  If you are outside the USA and your climate zone has changed, allowing you to expand your plant collection, please use whatever terminology suits you best.    

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When they updated the zones a few years ago I jumped from high 4 to a low 5.  This doesn't really do much for my container ranch other than allow me some extra weeks out on the balcony, maybe a less severe spring/fall.  

However, the added energy in the system means the extremes can swing hard and fast.  I have to keep a closer eye on the 5 to 10 day outlook.  Sometimes, if only for a day or 3, I have to pull everything in during early Spring or late Fall.  Obviously everything I have is long since pulled indoors by winter months, but I'm sure some gulf-coasters are starting the dread the increased potential for another Polar Vortex to surge south now that the Jet Stream is getting more destabilized...

tl;dr - I think most of us are getting a bump in average temps year-round, but the storm system extremes make that a risky trade-off.

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The last couple of summers have been extremely hot, with inland daytime highs clearing 100F with some regularity.  The last 2 falls were very hot the whole way through December, so the bodies of water were very warm when we did get a cold blast.  As a result, the winters have been in the "10a range", with annual lows in the low or mid-30s.  As @Funkthulhu mentioned, it does make it really hard to compensate for those wild temperature swings, in our case, from 85F down to 33F in little more than 24-48 hours.

2010 was a brutal winter, but the low (26F) was still in our listed 9b range.  It was just cold/chilly for roughly 2 weeks and wore tender plants down.

At this point, I think most of us in the western half of Central Florida are more worried about the lack of rain than anything.

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The climate has definitely shifted in central Florida with much warmer winters.

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When I was a little kid I remember it being much colder, not uncommon to see 28 at least once a year. Now the lowest temp I've seen in 8 years is 31 (09-10). 

 

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I think the recent urbanization in my area has contributed to a warmer microclimate in my immediate surroundings. I would endeavor to say this is a global event.

 

 

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While a topic that can stirr contentious debate, it is none the less an important discussion.  

While a firm believer in what i have personally observed, I will admit that I also share some degree of skepticism regarding the many different scenarios that have been presented regarding the degree that zone shifts may or are shifting towards the warmer. In the overall discussion, there is room for the effects of urbanization, and a general warming trend, accelerated by various influences.  

Here in Phoenix, there is no doubt that the area's growth is influencing both the effects of heat during the summers, and the lessening degree that we may experience sub 32f cold during the winter. Still, as most people know, such changes have been slower/ perhaps less noticeable in the outlying parts of town. Even so, these areas have also experienced the effects of an overall warming trend.. and may continue to do so, especially since a sizable swath of the area between Phoenix and Tucson is poised for substantial nearer term growth/ development, which most certainly will influence the local climate.

When I ponder how the areas  overall climate might change under warming scenerios, I always take the past into account. At one time, the region here likely expressed a climate similar to what currently exists around the border of Sonora and Sinaloa.. still dry, yet warmer, with summer precipitation having more influence,  thus being more tropical. 

During the last glacial period, the region was cooler with the effects of winter precipitation being more dominant. It is the coming out of that "cooler" period that allowed Saguaro, Ironwood, Creasote Bush, and Ocotillo to expand their range north. Under some suggested data, these indicators of the Sonoran Desert, and the eco-  region itself may continue to expand up into southern Nevada, and push further north into territory  currently occupied by the Mojave Desert in California.  It is well known that cold susceptability determined how far north succulent- type plants could establish themselves. This same influence also determined how far south temperate plants would be able to survive since many like it cooler/ colder. 

How fast such changes might happen depend upon what actually happens, no matter what 1000 graphs might depict. Anyone can easily realize that as the Northern boundaries of a climate shift "up", so will the core or southern boundries.. which would tend to be the warmer end of the spectrum. Here, it is plausible that most of the valley/ lower elevations areas between Phoenix and Yuma shift to a solid zone 10.. with favored core urban areas in the low deserts expressing 5-8 winters out of 10 that would qualify as borderline zone 11. As it stands, zone 10 is only depicted in the warmer parts of town, with outlying spots ranging between 9a and borderline 10a' ish. 

Still, even if such happens, there would likely still be intense, albeit brief cold spells. Like mentioned, there exist the likelihood that the jet stream exhibits wild fluctuations at times, bringing wild weather with it under a warmer overall climate.  I highly doubt a time would come that one could say " Phoenix hasn't been below 40 degrees in 25 years.." 

Interestingly, I came across a hypothetical study from the Institute of Physics science department that showed, in their analysis, a similar warming in the coming decades. This same study also looked at the extant that such crops and Oranges, Kiwi, and Almonds could be cultivated in the future, if such changes occur. Again, this is hypothetical, though plausible. This same study also seems to push zones 5 or lower out of the U.S. entirely. 

As ive likely stated a few times before, another thing worth noting when considering a warming climate is the wildlife aspect. What and who is expanding their range, ..wintering in areas where they might  have vacated in the past to escape cold exposure.. What insects are not dying off from cold exposure, etc.. this aspect  can show obvious trends over time. Ongoing data from such places as Ebird and other sites that collect daily/monthly/yearly data through field observations yields some interesting results. 

In any event, I think we'll see trees like Royal Poinciana, African Tulip Tree, and other cold sensitive stuff considered quite marginal here become more commonly encountered locally. Heck, i'd even go out on a limb and say one might even come across some decent Coconuts.. maybe even a few nicely grown Veitchia, or Adonida specimens in a super ideal shady spot in someone's yard here.  How likely? Hard to say.. we all know our flavor of summer heat is likely a bigger limiting factor as far as success of these palms, or any other tropical that dislike aridity.

I also think the ideal of encountering some nice looking Coconuts somewhere along the far southern California coast, or being able to cultivate Oranges in New Mexico or parts of the Pac. Northwest isn't as far fetched as might be assumed. 

Really, I think more people would benefit from a milder climate than not, even if there are drawbacks to be taken seriously as well. Only time, not hypothesis, will tell.

For now, enjoy what "else" you might be able to cultivate, or how far you might be able to push the envelope.  Perhaps the time is right to see who can grow the first Florida grown and fruited Mangosteen?.. or Cloves. 

 

 

 

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There hasn't been a real killing freeze (<27/28F) in Brownsville, Texas since 1989. The extreme southern coast is even milder and zone 11 winters are not uncommon. Going to be a sad day when a real freeze kills all the tropicals. But if the mild string continues, maybe we'll see some more coconuts pop up in S. Texas. 

As for Houston, the heat island really helps in a radiational freeze...but the one freak advective freeze every now and then really ruins everything. Zone 10 plants sometimes survive for years and get quite big until a freeze strong enough to damage queen palms completely torches them. Still, Bismarckia and Ravenea rivularis (bud hardy) are good choices for the warmer parts of town. Galveston comfortably averages zone 10 for the last 20 years.

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Posted (edited)

We've had a particularly nasty winter, no so much in extreme cold, but long and lingering wet and periodic cold. So in this case the numbers still state zone 8b, but it's taken a greater toll than cooler years with shorter duration. USDA numbers mean very little on overall plant health, only a basic guideline. 

Edited by Las Palmas Norte
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Posted (edited)

Mangosteen was fruited outdoors in Bal Harbor Florida for the first time in the 1960s and then a bunch of times after that, at the same location. (Bill Whitman)

If you can find one, Five Decades with Tropical Fruit is packed with fruitawsome takes of tropical fruits!

 

I say that because of the mangosteen comment, and I can't figure how to qoute on my phone, so it seems wonky. 

Edited by Alan_Tampa
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Sorry, it was 1976

1494029462767-2141300935.jpg

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Past seven years have been solid 10b borderline 11a in a normal 10a zone here in Cape Coral... Southwest Florida.  Also much more humid than normal.  All good.  Now if we could get some substantial rains.  Come on rainy season!!  

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Much of NYC and the eastern tip of Long Island now sit on the borderline of zone 7b and 8a. Only the hardiest palms will survive that, of course, but it's better than nothing. I'm actually more concerned about rain and melting snow causing rot than the actual cold itself.

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Zone 10a.  No changes in the last 10 years.

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Zone 10A........but my plants think it's zone 11!

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Posted (edited)

10 years ago the airport was label as 7b it now 8a on zonal maps. 

Edited by Palm crazy
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I don't pay much attention to temperature records but my plant behavior has changed in the last few years.  I have one Rhododendron 'Noyo Chief', (said to be a cultivar of R. arborescens).  The flower trusses would be open between April 15th and May 30th, exactly 6 weeks, for 15 years.  For the last 3 years the trusses begin in February and the last ones are still out in August.

Archontophoenix cunninghamiana, Chamaedorea carchensis (benzei), and Rhopalostylis baueri have all recently made seeds for the first time, even though they previously had flowered for many years.   

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Albuquerque: where I lived 21+ years and specified many plants in my practice plus in my own 2 home gardens, I saw no change in what could grow for more than 5 or 10 years and survive the winter. Except that the last 5 years or so, the weather had become more unstable in the cold front, last spring freeze, or first fall freeze category. Their National Weather Service office published a narrative years ago how warmer daytime highs in winter or summer were down, but nighttime lows were up, both with increased winds and cloud cover...net change +1F in annual mean temps. Another source noted ABQ's annual snowfall and heavier snow events (>2" per storm) had increased recently. We'll see in another 20-30 years if those are changes in climate, or just shorter-term weather spells. But I would not hang my professional hat on using every plant there that grows well in El Paso or Las Cruces.

Las Cruces and El Paso: where I've now lived 4 years, also specifying many plants in landscapes nearly 20 years. Though 200-250 miles as the crow flies from ABQ, it seems the growing season is longer and there are less cold waves (less, not more, cold waves and untimely freezes or snows from jet stream dips than ABQ), though the 20 year freeze event in 2/2011 took care of the Phoenix-pushing some of my colleagues and hobbyists did.

I attribute both trends to a 3 deg change in latitude and distance from the winter storm track or polar jet more than elevation, and that trend is only 25 years so far. One thing in either place: more plants are available and being tried than ever, often from big box stores or from out-of-area wholesale growers, since not all local growers are into desert native and adapted plants yet.

More plant variety used does not = warming, as climate reality has been warmer than many perceptions in ABQ, but has been cooler than many perceptions here. 

Climate data for enough places and long enough = warming or other climate trends. NOAA data shows 1960-1990 was the coolest period in 100 years in the SW, so of course it's warming from that. Is there added instability in some locations but just warming in others since...my limited observations are "yes".

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Hopefully, we will avoid the "Ice Fairs" in London in 1814, when the Thames River froze repeatedly. That was due to a "Mini Ice Age" that can roll out of nowhere based upon a solar slow down. Apparently, the sunspots are minimizing now according to some scientific reports. No more coconuts! 

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This winter i had about a dozen birds around the house freeze and die during that freak cold front. I should have taken a picture of them but i suspect they were a southern species that didnt fly south because of the warm weather and suffered the consequences. 

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The winter of 2016-17 has been the warmest winter for me in the 20 years I've lived in Florida. But, that being said, December of 2010 was a very, very bad winter, so much so that December of 2010 went down (for Florida and Georgia) as having the lowest average temperature for December since records have been kept.

You can still view Google street view photos taken in the spring of 2011 of many tropical species palms that were hurt by the December of 2010 cold and freezes, even in many coastal areas of south Florida.

My area is rated as USDA 9b. I haven't been below 30 degrees for the past four winters or below 35 this past winter. I actually sprouted two coconuts (from my coconut palm) that I partially planted in the ground up against the south exterior wall of my house.  So, that was a first for me (germinated a coconut outside a greenhouse over the winter months).

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Not much in my area in terms of warming. I am 8b, and since 2007, we've gotten dub 20 degree temps every few years or so (those years were 2010, 2014, and 2015). The zone 9 stuff somewhat "survives" in between the sub 20 degree winters. However, 2014 was brutal with 17 degrees, an entire day below freezing, followed by a freezing rain/sleet event that put the last nail in the coffin for many of the zone 9 and warmer stuff. However, the 2015-2016 winter was the warmest I've seen with the lowest getting to 25 deg. It was enough for queen palms to survive.

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Even here in the tropics, there may be changes afoot.  My armchair climate research revealed climatologist observations that our northeast trade winds have shifted to the east since the 1940s, a phenomenon I have noticed  (climate books always refer to Hawaii's tradewinds as blowing out of the semi-permanent high pressure cell way up to our northeast).  It matters because easterly winds seem to result in decreased orographic rainfall for windward regions, at least on the Big Island where I live.  This year, East Hawaii has not had regular rainfall patterns.  It has been a case of long dry spells interspersed with deluges.  Just normal interannual fluctuation or a sign of long-term change?

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On 6/19/2017, 10:15:13, Walt said:

The winter of 2016-17 has been the warmest winter for me in the 20 years I've lived in Florida. But, that being said, December of 2010 was a very, very bad winter, so much so that December of 2010 went down (for Florida and Georgia) as having the lowest average temperature for December since records have been kept.

You can still view Google street view photos taken in the spring of 2011 of many tropical species palms that were hurt by the December of 2010 cold and freezes, even in many coastal areas of south Florida.

My area is rated as USDA 9b. I haven't been below 30 degrees for the past four winters or below 35 this past winter. I actually sprouted two coconuts (from my coconut palm) that I partially planted in the ground up against the south exterior wall of my house.  So, that was a first for me (germinated a coconut outside a greenhouse over the winter months).

Out in Northern California this past winter was the coolest on record. So hopeful for a warmer winter this time and since east is usually opposite, you'll share some cold this time :) lol

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5 hours ago, enigma99 said:

Out in Northern California this past winter was the coolest on record. So hopeful for a warmer winter this time and since east is usually opposite, you'll share some cold this time :) lol

Thanks anyway -- but I will pass!

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I'll see Walt's pass, and raise you a #3ll N0!

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So far no big change in Guada La Habra.

But, the Arctic and Antarctic are melting. A guy my age had his picture taken in his mother's arms in Glacier National Park in 1960; the glaciers came up to the road. Now, they're all gone. Not receded, but gone.

Having lived the first 25 years of my life in a cold winter climate, I can tell you that when conditions are right, prodigious melting can occur with stunning speed. A mountain of ice and snow vanishes in a whoosh of meltwater. What's scary is that conditions were right for that, but didn't seem to you they'd be right for that.

We'll probably also see increased tropical storm activity, particularly further north. Will Hurricane/Superstorm Sandy become a regular event in NYC? Hope not.

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Here in Western Pasco county just north of Clearwater, the past 6-7 winters have been wonderful. I believe I touched freezing one night somewhere in there, but that makes me a solid 10a wherein I plant for 9b just in case. The amazing thing is my Mango Tree - which I use as a shade tree - is well over 40 feet tall with mangoes all fruited on top...not that I can reach them, It has delighted that corner of the yard with much needed shade. That nasty winter we had in 2010 (I think) was my last 9b winter with many nights in the upper 20'sF. Ive even got Corn Plants (Draceana) that tower so high over the roof I can not reach the tops if I was standing on the roof. My Fishtail towers above the house. All this shade makes it easier growing, too. ^_^

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I have noticed the winters got very very slightly warmer here but nothing major. If this map is true (which I have seen other people post before) I better get some Sabal palmetto started. Haha.

Figure-31-hi.jpg

Edited by PalmTreeDude
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I have not seen this map before. Do you know who produced that map?  Is it based on reliable scientific data or is it someone's speculation?  Where was it published? 

I would be surprised if those areas of Texas close to Oklahoma became zone 9 any time soon. My reaction is the same for those parts of Louisiana which approach the Arkansas border.  Likewise, that map has zone 9 up as far as Macon, GA almost.  That seems unlikely.  It would have where I live, Gainesville, Florida, remaining in zone 9, and therefore in the same zone as Macon, GA.  That is hard to imagine because I have done that drive several times in winter and the climates are totally different.

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6 hours ago, Sandy Loam said:

I have not seen this map before. Do you know who produced that map?  Is it based on reliable scientific data or is it someone's speculation?  Where was it published? 

I would be surprised if those areas of Texas close to Oklahoma became zone 9 any time soon. My reaction is the same for those parts of Louisiana which approach the Arkansas border.  Likewise, that map has zone 9 up as far as Macon, GA almost.  That seems unlikely.  It would have where I live, Gainesville, Florida, remaining in zone 9, and therefore in the same zone as Macon, GA.  That is hard to imagine because I have done that drive several times in winter and the climates are totally different.

NOAA is the source.

https://www.google.com/amp/s/fivethirtyeight.com/features/two-government-agencies-two-different-climate-maps/amp/

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Oh wow, that is a reliable source --

... which makes those projections all the more scary.

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23 hours ago, TexasColdHardyPalms said:

I wouldn’t be surprised if, with these changes bound to happen, the lower Rio Grande Valley of Texas be placed in borderline zone 11a. This will most certainly would place the area in a tropical savannah climate under Köppen requirements. The greater Brownsville area has average temps that miss tropical climate clasification by 2-3 degrees. Even then, it currently is transitional between subtropical and tropical. Looking forward to seeing the Valley flourish with more tropical plants. 

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I don't buy the prediction.  The models have been running hot of the actuals.  

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29247841-eaf7-41d4-9a90-7e3fcee9c779.thu94b47912-e991-44e7-9ece-972dc2ef91ef.thu

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I suspect that greater variability will be characteristic of climate change.  While there might be substantially warmer winters in many locations, there may also be swift or prolonged intrusions of arctic air that just as quickly retreat.  Nevertheless, the damage would be done.  

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In the last 14 years my garden experienced 3 times snow fall, while in the previous 17 only once and that time was with warmer air.

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Here in most of the Europe last winter was the coldest in 40-50 years. We even had a snow for one day here in Dubrovnik which is not normal. Even North Africa had snow last winter.

Even our native plants were damaged by cold. It was record cold in some parts.

Soo people do not be too excited about the warm winters promise. Climate is changing. It can be colder too.

Edited by Cikas
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3 hours ago, Cikas said:

Here in most of the Europe last winter was the coldest in 40-50 years. We even had a snow for one day here in Dubrovnik which is not normal. Even North Africa had snow last winter.

Even our native plants were damaged by cold. It was record cold in some parts.

Soo people do not be too excited about the warm winters promise. Climate is changing. It can be colder too.

That is true, Climate change is marked also by extreme temperature swings, so it definitely does swing both ways.

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