What with all this global warming, why isn't spring getting any earlier in the US?

Question

A recent peer-reviewed study, ""Intercomparison, interpretation, and assessment of spring phenology in North America estimated from remote sensing for 1982-2006"" by Michael White et al, did the most complete survey ever undertaken of the arrival of spring in North America and found: [quote]

""We found no evidence for time trends in spring arrival from ground- or model-based data; using an ensemble estimate from two methods that were more closely related to ground observations than other methods, SOS trends could be detected for only 12% of North America and were divided between trends towards both earlier and later spring.""

~ So why hasn't the onset of spring changed significantly for decades if global warming is real and perceptible?
.

Answer 1

Bob's citations are not actual links, so you won't read the articles and see that they are only peripherally linked to his argument: for instance the first theorises that wildfires are caused by earlier onset of spring, but doesn't prove the early onset.

Throw enough irrelevant publications at skeptics and maybe they'll go away?

Answer 2

GLobal warming takes a long time! Chill and before you know it, spring will be here. ONe warm day does not mean global warming had anything to do with it. The emperature of the whole earth averaged together will give you the global warming percentage. Spring also has gotten earlier by about 3.8394%. Don't keep your hopes up though. Global warming is just a belief, it is not necessarially true. Just because the earth is warmer doesn't mean global warming has anything to do with it. about 7 million years ago, the earth went tinto a hot stage where everything was just desert. This may happen again, but not for millions of years. And if you can live that long, you will sizzle.

Answer 3

I'm not clear how you are defining "spring". Obviously, there are multiple definitions (e.g. astronomical, botanical, etc.)



But the first problem I see with your insinuation is that 1982 to 2006 is simply not a long period. Finding statistical significance to a two sigma confidence interval would be challenging for a mere 24 years, I would think.



I've personally not studied the topic in depth. But I know enough about biology to mention that all sorts of "spring awakenings" are related not so much to climate as to length of day. Obviously, length of solar day is not impacted by temperature trends. (Indeed, when i was a tropical bird enthusiast I would tamper with artificial length-of-day factors in order to induce birds to lay eggs more often without waiting until literal "spring" came to the colony. I used computer-based timers to modify the birds' understanding of the seasons.)



My hunch? Dunning-Kruger strikes again.

Answer 4

Did you read the study? Did you even notice the objective of the study?



The primary purpose was to learn whether the 10 methods of measuring start-of-spring could be used in a comprehensive manner. Isolating a trend in SOS was as side-bar and not the purpose for which the study was constructed. But they used their data to see what they could learn, and found with statistical significance sites with trends to earlier SOS exceeded sites with later SOS.



They've got a lot of messy data here, and a lot of noise. Several of methods they were using were degrees of greening to signal SOS. Greening is tied to the length of daylight more than temperature, so that creates a lot of noise. Add that every year has its own weather.



The authors conclusions:

There is no reason to prefer one of ways to measure SOS over another. In other words, this was research about research.



They do go on to note that they found "no or limited" trends to earlier SOS but that a "SOS is short for detecting robust trends".



Any farmer or grower will tell you that the start of Spring varies widely every year. Even when there is a trend you are not going to find it with statistical significance when there is so much randomness in the outcomes and you have only 25 data points. It's common statistics.

Answer 5

It is. I'll give the actual citations, so you can read them for yourself.



Westerling, et al, (2006), Warming and Earlier Spring Increase Western U.S. Forest Wildfire Activity, Science, Vol. 313. no. 5789, pp. 940 - 943



Schwartz, M. D., Ahas, A., & A. Aasa, 2006. Onset of spring starting earlier across the Northern Hemisphere. Global Change Biology 12: 343-351



Wolfe, D. W., Schwartz, M. D., Lasko, A. N., Otsuki, Y., Pool, R. M., & N. J. Shaulis, 2005. Climate Change and Shifts in Spring Phenology of Three Horticultural Woody Perennials in Northeastern USA. International Journal of Biometeorology 49: 303-309



Also summer:



Crimmins, T., M. Crimmins, D. Bertelsen. 2009. Flowering range changes across an elevation gradient in response to warming summer temperatures. Global Change Biology, 15: 1141-1152



Claiming this isn't happening is as silly as claiming we're actually cooling.



EDIT - Contrary to the claim below, the first paper is DIRECTLY relevant to early Springs. A quote:



"Changes in spring and summer temperatures associated with an early spring snowmelt come in the context of a marked trend over the period of analysis."



and it also references:



Stewart, et al, (2005), Changes toward Earlier Streamflow Timing across Western North America, Journal of Climate, 18:8, pp. 1136–1155 and



Cayan, et al, (2001) Changes in the Onset of Spring in the Western United States, Bulletin of the American Meteorological Society, 82:3, pp. 399–415



The poster kindly gave the link (which wasn't at my fingertips), I'll repost it so people can see who's telling the truth here.



http://www.sciencemag.org/cgi/content/full/313/5789/940

Answer 6

Seems like someone does not understand the difference between local weather and global climate.

Answer 7

because as 1 person says there's a + or - of 20 days, with that kind of leeway spring will be here either March 1 or April 10 so if it fits in there somewhere spring is early

Answer 8

Perhaps because we are experiencing nothing more than a natural warming cycle that has been going on for thousands of years!

Answer 9

What study was that? Who did it? How was the data collected? Who sponsored the study and who paid for it. What are Micheal Whites' qualifications? Was this a university study or a commercial study? Who did the peer review? I'll check this out and get back to you!

Answer 10

Why didn't this study for that the arrival of spring changed between 1982 and 2006?



Maybe because the standard deviation of their study was +/- 20 days.

Answer 11

Global Warming isn't real. News flash! It's just a scam that has made Al Gore rich.

Answer 12

Ask the groundhog. He is smarter than those AGW activists, because he saw his shadow and crawled back into his hole.



Here are some links that might interest you

http://www.forbes.com/2009/12/03/climate-science-gore-intelligent-technology-sutton.html

http://www.timesonline.co.uk/tol/news/environment/article7026317.ece

http://www.telegraph.co.uk/earth/environment/globalwarming/7153621/Greenpeace-director-tells-IPCC-boss-Rajendra-Pachauri-to-stand-down-over-glacier-claim.html

http://online.wsj.com/article/SB10001424052748704804204575069440096420212.html

http://www.telegraph.co.uk/earth/environment/climatechange/7157590/India-forms-new-climate-change-body.html

Climategate U-turn as scientist at centre of row admits: There has been no global warming since 1995

Read more: http://www.dailymail.co.uk/news/article-1250872/Climategate-U-turn-Astonishment-scientist-centre-global-warming-email-row-admits-data-organised.html#ixzz0g1scUimq

http://www.sciencedaily.com/releases/2009/12/091230184221.htm

http://www.businessandmedia.org/specialreports/2006/fireandice/fireandice.asp

Our planet has been getting cooler for 6000 years

http://commons.wikimedia.org/wiki/File:Holocene_Temperature_Variations.png