INTERESTING UPDATE: Global Warming - Accuracy of the USDA Hardiness Map 1990

It has been brought to my attention that I may no longer consider myself to be in zone 7 here in Piedmont North Carolina.  I see some people have been citing from the Arbor Day hardiness map which states I am now in the upper zone 8.  Trying not to jump into any conclusions but this is very confusing.  I am ashamed to say I would be happy to hear hear this, but Because the USDA only updates its hardiness map every 15 years, I am curious of its validity for today.  The last update was done in 2004 but it is hard to verify an authentic 2004 map. 

I know there is a bit of difference today then from 1990 but the USDA maps off the net have some fluctuations.  Further confusing is the interactive map endorsed on the USDA website http://www.usna.usda.gov/Hardzone/ushzmap.html? which clearly states it is a version from 1990 that was web optimized in 2003.  Is it relevant for today?  On the very bottom left hand corner there is a link to the 2004 USDA hardiness map here http://www.usna.usda.gov/Hardzone/ushmap.html but the link is dead.  Incite would be appreciated.


SO, I was trying to find an updated USDA hardiness map but just found out that do to political pressure they still use the 1990 map because the 2004 map shows that the United States is getting warmer.  This is why the 2004 link I mentioned earlier is now dead.  Every 15 years the USDA is supposed to provide an updated map.

Any map based on the 1990 map is out of date.  Some sites still post the old map.

The new Arbor Day Foundation map:  http://www.arborday.org/media/zones.cfm

The USDA is working on a new map, which will probably be slightly different from the Arbor Day map.

The USDA is under pressure not to release a new map, as it would be seen as an acknowledgment of global warming.

honestly I think BOTH of those maps are wrong..there was an updated map put out a while back that has us in totally different zone then the newest one above shows..we are zone 4 where the newer map above has us in zone 5

I would recommend finding an airport or local weather station that is at a similar elevation and aspect and get the best available time series data on mix-mean-max temperature that you can.  You could develop your own metrics by month.  Also look in the PDF version of your county soil survey published by NRCS... which contains information about local growing conditions including things like mean frost free days.  Track you local microclimate and compare that in real time to your known climate station to understand the way your site (in general) deviates from the mean local climate.

I live in a drainage receiving portion of glacial plateau around 150 feet above sea level near an inland sea.  My local low temp can be 5 degrees lower than the airport that is better drained and likely located in an asphalt heat island.  People in town can grow rosemary and artichokes, whereas I get frozen out without heroic measures.  A pond with an elevated heat trap to the north, or some creative management of airflow around my south facing patio would likely solve that problem.

I'd agree with the idea that USDA zones are THE MOST primitive understanding of climate available.

I don't know about "proven incorrect" (the average global temperatures are actually at their highest in recorded history and have been for some time), but a rise in global average temperature does not imply a rise in temperature everywhere. Some places will definitely get cooler, but on average, the zones have been drifting north for some time. In 1936, zone 2 occupied a swath of the northern United States, and now zone 3 has almost disappeared across the Canadian border. Northern climes are warming much more than the tropics.

Oh, and don't forget about microclimates

Ditto Paleo.. Most scientists don't talk about 'global warming' any more.  The exciting new stuff is using complex models to predict global climate instability.  Mean temp can increase and winter low drop.

I must admit that I am pretty surprised to see climate skeptics here but I am not here to debate this.

Here is a good non-biased video on this politically charged issue of global warming:
http://www.youtube.com/watch?v=6hCRafyV0zI&feature=player_embedded#at=739

Here is the most reputible source of global warming information:
http://www.ipcc.ch/

Stuff deleted for stating "the truth" instead of "my position".

I wanna remind folks that I don't want these forums to be a place to talk about politics, there are other forums for that.  Some of you might wanna edit your posts.

Yeah Paul!  Politics and Religion are the only two things were I'm right and you're wrong. Let's keep both of those outa here.

For those of us on the west coast, the Sunset zone system is a much better guide to growing conditions. I hear rumors from time to time that they intend to do the rest of the country, but that may just be wishful thinking.

I just want to state that when I started this thread I had absolutely no intentions of having a political discussion.  What had happened is that I accidentally stumbled on a political situation which was the cause for me to be unable to locate an up to date USDA zoning map.  I did not know there was a political motive for the censorship of the map information I was seeking, it was just revealed to me.

NOAA recently released the new 30 year normals (1981-2010 period). Most of the data are still in a raw format but an "average annual minimum temperature" map is available at http://www.climatewatch.noaa.gov/article/2011/the-new-climate-normals-gardeners-expect-warmer-nights-2/2 (just below the map are controls that allow for comparision between the current and previous normals). The scale on that map also shows planting zones. There is a clear shift northward in zones across the continent.

well we had our coldest summer on record last year and may hit our hottest summer on record this year..so whether there is an accurate zonal map or not we'll always have cold and hot years that don't meet the criteria.

this is sure a hot one..which may convince a lot of people of the warming changes..but when you have record cold weather like we did last summer...you wonder

Thing is, when it gets cold in the winter, folks will ask "so where's the global warming?"  I think most people don't bother to try to learn much about it, and of course it's much more pleasant to think it isn't happening at all. 

Brenda Groth wrote:
well we had our coldest summer on record last year and may hit our hottest summer on record this year..so whether there is an accurate zonal map or not we'll always have cold and hot years that don't meet the criteria.

this is sure a hot one..which may convince a lot of people of the warming changes..but when you have record cold weather like we did last summer...you wonder

2010 was the fourth hottest summer on record in the United States.  The big picture is quite consistent with volumes of other information that point to a climate that is changing towards being hotter.

http://www.sciencedaily.com/releases/2010/09/100913165150.htm

http://en.wikipedia.org/wiki/2010_Northern_Hemisphere_summer