Season creep

Cherry blossoms in Japan have been emerging earlier in recent years due to climate change
Changes in pollen season in the United States, 1995 to 2013.

In phenology, season creep refers to observed changes in the timing of the seasons,[1][2] such as earlier indications of spring[3] widely observed in temperate areas across the Northern Hemisphere.[4][5] Phenological records analyzed by climate scientists have shown significant temporal trends in the observed time of seasonal events,[6][7] from the end of the 20th century and continuing into the 21st century.[5][8] In Europe, season creep has been associated with the arrival of spring moving up by approximately one week in a recent 30-year period.[9][10] Other studies have put the rate of season creep measured by plant phenology in the range of 2–3 days per decade advancement in spring, and 0.3–1.6 days per decade delay in autumn, over the past 30–80 years.[11]

Observable changes in nature related to season creep include birds laying their eggs earlier and buds appearing on some trees in late winter.[12] In addition to advanced budding, flowering trees have been blooming earlier, for example the culturally-important cherry blossoms in Japan,[13][14] and Washington, D.C.[15][16][17] Northern hardwood forests have been trending toward leafing out sooner, and retaining their green canopies longer.[18] The agricultural growing season has also expanded by 10–20 days over the last few decades.[19]

The effects of season creep have been noted by non-scientists as well, including gardeners who have advanced their spring planting times,[20] and experimented with plantings of less hardy warmer climate varieties of non-native plants.[21] While summer growing seasons are expanding, winters are getting warmer and shorter, resulting in reduced winter ice cover on bodies of water,[22] earlier ice-out,[23] earlier melt water flows,[24] and earlier spring lake level peaks.[25] Some spring events, or "phenophases", have become intermittent or unobservable; for example, bodies of water that once froze regularly most winters now freeze less frequently,[8][26][27] and formerly migratory birds are now seen year-round in some areas.[28]

  1. ^ Gabay, Jonathan (2006). "23. So What's New?". Gabay's Copywriters' Compendium (Second Edition: The Definitive Professional Writers Guide ed.). Oxford: Butterworth-Heinemann. pp. 701. ISBN 978-0-7506-8320-3. Season creep n. Earlier spring weather and other gradual seasonal shifts caused by global climate change.
  2. ^ Maxwell, Kerry (18 September 2006). "Macmillan English Dictionary Word Of The Week Archive - "Christmas creep"". New Words. Macmillan Publishers. Archived from the original on 20 March 2007. Retrieved 26 December 2007. ...season creep, earlier spring weather and seasonal shifts caused by global climate change
  3. ^ Maxwell, Kerry (December 2007). "A review of 2007 in twelve words". MED Magazine. Macmillan English Dictionaries. Retrieved 23 December 2007. It's a classic case of the newly identified phenomenon of season creep, where Winters are warmer and Spring arrives earlier.
  4. ^ Schwartz, M. D.; Ahas, R.; Aasa, A. (2006). "Onset of spring starting earlier across the Northern Hemisphere". Global Change Biology. 12 (2): 343–351. Bibcode:2006GCBio..12..343S. doi:10.1111/j.1365-2486.2005.01097.x. S2CID 86329402. SI first leaf dates, measuring change in the start of 'early spring' (roughly the time of shrub budburst and lawn first greening), are getting earlier in nearly all parts of the Northern Hemisphere. The average rate of change over the 1955–2002 period is approximately -1.2 days per decade.
  5. ^ a b Cite error: The named reference Cleland2006 was invoked but never defined (see the help page).
  6. ^ McFedries, Paul (August 2006). "Changing Climate, Changing Language". IEEE Spectrum. Archived from the original on 15 April 2013. Retrieved 23 December 2007. Did spring seem to arrive a bit earlier than usual this year in your part of the world? That wouldn't be surprising, because we seem to be undergoing season creep: earlier spring weather and other gradual seasonal shifts, particularly those caused by global climate change.
  7. ^ Sayre, Carolyn (17 December 2006). "The Year in Buzzwords 2006". TIME. Archived from the original on 21 January 2007. Retrieved 26 December 2007. SEASON CREEP n. Spring seemed to come early this year--and summer lasted a bit longer. What's to blame? Most scientists say global warming.
  8. ^ a b Skinner, Victor (17 February 2007). "Area temperatures expected to rise back to 'normal'". Traverse City Record-Eagle. Retrieved 27 December 2007. ...the west arm of Grand Traverse Bay ... has only frozen over five times since 1987,.... Between 1851 and 1980, [it] froze at least seven years per decade, ... the bay-freezing trend shows 'a long-term gradual decline with a significant decline in the past 25 to 35 years.'
  9. ^ Stutz, Bruce (21 April 2006). "Suddenly spring". The Record (Bergen County, NJ). Archived from the original on 16 May 2011. Retrieved 23 December 2007. In fact, due to global warming, spring across the Northern Hemisphere arrives a week or more earlier than it did 30 years ago, a phenomenon starting to be known as "season creep."
  10. ^ "Climate changes shift springtime : A Europe-wide study has provided "conclusive proof" that the seasons are changing, with spring arriving earlier each year, researchers say". Science/Nature. BBC News. 25 August 2006. Retrieved 28 December 2007. Spring was beginning on average six to eight days earlier than it did 30 years ago, the researchers said.
  11. ^ Sherry, R.A.; Zhou, X.; Gu, S.; Arnone Iii, J.A.; Schimel, D.S.; Verburg, P.S.; Wallace, L.L.; Luo, Y. (2007). "Divergence of reproductive phenology under climate warming". Proceedings of the National Academy of Sciences. 104 (1): 198–202. Bibcode:2007PNAS..104..198S. doi:10.1073/pnas.0605642104. PMC 1713188. PMID 17182748. Phenology is a sensitive biosphere indicator of climate change. Long-term surface data and remote sensing measurements indicate that plant phenology has been advanced by 2–3 days in spring and delayed by 0.3–1.6 days in autumn per decade in the past 30–80 years, resulting in extension of the growing season.
  12. ^ Cite error: The named reference Scotsman.com was invoked but never defined (see the help page).
  13. ^ Miller-rushing, A.J.; Katsuki, T.; Primack, R.B.; Ishii, Y.; Lee, S.D.; Higuchi, H. (2007). "Impact of global warming on a group of related species and their hybrids: cherry tree (Rosaceae) flowering at Mt. Takao, Japan". American Journal of Botany. 94 (9): 1470–8. doi:10.3732/ajb.94.9.1470. PMID 21636514. We examined a 25-yr record (1981–2005) of flowering times for 97 trees, representing 17 species and hybrids of cherry (Cerasus sp. or Prunus sp.) grown at Mt. Takao, in Tokyo, Japan. The cherry trees flowered earlier over time, by an average of 5.5 d over the 25-yr study.
  14. ^ Cleland, E.E.; Chuine, I.; Menzel, A.; Mooney, H.A.; Schwartz, M.D. (2007). "Shifting plant phenology in response to global change" (PDF). Trends in Ecology & Evolution. 22 (7): 357–365. doi:10.1016/j.tree.2007.04.003. PMID 17478009. S2CID 34408962. Retrieved 29 December 2007. The longest and best known phenological records come from the Far East and Europe, including ... the 1300+-year Kyoto cherry blossom time series [37]... These longterm historical records can serve as proxies for temperature where thermometer data are unavailable.
  15. ^ Abu-asab, M.S.; Peterson, P.M.; Shetler, S.G.; Orli, S.S. (2001). "Earlier plant flowering in spring as a response to global warming in the Washington, DC, area" (PDF). Biodiversity and Conservation. 10 (4): 597–612. Bibcode:2001BiCon..10..597A. doi:10.1023/A:1016667125469. S2CID 21391086. Retrieved 27 June 2009.
  16. ^ Peterson, Paul M.; Stanwyn G. Shetler; Mones S. Abu-Asab; Sylvia S. Orli (2005). "Chapter 8 Global Climate Change: The Spring Temperate Flora". In Krupnick, Gary A; W. John Kress (eds.). Plant conservation: a natural history approach. Chicago: University of Chicago Press. p. 192. ISBN 978-0-226-45513-6. Finally, there is the Cherry Blossom Festival in Washington, DC, each spring. On average the two principal species, Prunus serrulata (Kwanzan cherry and other varieties) and P. X yedoensis ( Yoshino cherry), bloom six and nine days earlier, respectively, than they did in 1970.
  17. ^ Chung, Uran; Mack, Liz; Yun, Jin I.; Kim, Soo-Hyung (2011). Harvey, Jeffrey A (ed.). "Predicting the Timing of Cherry Blossoms in Washington, DC and Mid-Atlantic States in Response to Climate Change". PLoS ONE. 6 (11): e27439. Bibcode:2011PLoSO...627439C. doi:10.1371/journal.pone.0027439. PMC 3210174. PMID 22087317. The expected changes in phenology will have a substantial effect on the reproduction, distribution and productivity of trees as the coincidence of ecosystem processes, such as flowering and the emergence of pollinators, is disrupted. Some plants may also become less resistant to environmental challenges. For example, shorter and warmer winters can reduce the cold hardening of trees, leaving them vulnerable to frost injury.
  18. ^ Richardson, A.D.; Bailey, A.S.; Denny, E.G.; Martin, C.W.; O'Keefe, J. (2006). "Phenology of a northern hardwood forest canopy". Global Change Biology. 12 (7): 1174–1188. Bibcode:2006GCBio..12.1174R. CiteSeerX 10.1.1.495.6146. doi:10.1111/j.1365-2486.2006.01164.x. S2CID 10717334. ...significant trends (P≤0.05) towards an earlier spring (e.g. sugar maple, rate of change=0.18 days earlier/yr), consistent with other studies documenting measurable climate change effects on the onset of spring in both North America and Europe. Our results also suggest that green canopy duration has increased by about 10 days (e.g. sugar maple, rate of change=0.21 days longer/yr) over the period of study.
  19. ^ Linderholm, H.W. (2006). "Growing season changes in the last century" (PDF). Agricultural and Forest Meteorology. 137 (1–2): 1–14. Bibcode:2006AgFM..137....1L. doi:10.1016/j.agrformet.2006.03.006. Archived from the original (PDF) on 20 July 2011. Retrieved 27 June 2009. The evidence points to a lengthening of the growing season of ca. 10–20 days in the last few decades, where an earlier onset of the start is most prominent. This extension of the growing season has been associated with recent global warming.
  20. ^ Smith, Virginia A. (7 April 2007). "Out on a limb: Gardeners excited by the early warmth — call it "season creep" - are experimenting with earlier planting and new varieties". The Philadelphia Inquirer. Retrieved 23 December 2007. ...earlier springs — an idea known as "season creep" — may or may not be related to long-term warming trends. Yet the reality of year-to-year weather weirdness recently, coupled with the ever-present impulse to outsmart Mother Nature, has prompted more than a few gardeners to shun conventional horticultural wisdom.
  21. ^ Williams, Brad (8 April 2007). "Dogwoods to frogs, tulips to snow, Knox shows signs of warming". Knoxville News Sentinel. Retrieved 23 December 2007. Knoxville is now in hardiness Zone 7, a zone where more southern trees and shrubs flourish. The zone shift can be seen all across the northern half of the state. It effectively means plants that once had difficulty growing here are now finding it easier to thrive, said Lisa Stanley, master gardener at Stanley's Greenhouses
  22. ^ Magnuson, J.J.; Robertson, D.M.; Benson, B.J.; Wynne, R.H.; Livingstone, D.M.; Arai, T.; Assel, R.A.; Barry, R.G.; Card, V.; Kuusisto, E.; et al. (2000). "Historical Trends in Lake and River Ice Cover in the Northern Hemisphere". Science. 289 (5485): 1743–1746. Bibcode:2000Sci...289.1743M. doi:10.1126/science.289.5485.1743. PMID 10976066. S2CID 37999241. Freeze and breakup dates of ice on lakes and rivers provide consistent evidence of later freezing and earlier breakup around the Northern Hemisphere from 1846 to 1995. Over these 150 years, changes in freeze dates averaged 5.8 days per 100 years later, and changes in breakup dates averaged 6.5 days per 100 years earlier;
  23. ^ Hodgkins, G.A.; Ii, I.C.J.; Huntington, T.G. (2002). "Historical Changes In Lake Ice-out Dates As Indicators Of Climate Change In New England, 1850--2000" (PDF). International Journal of Climatology. 22 (15): 1819–1827. Bibcode:2002IJCli..22.1819H. doi:10.1002/joc.857. S2CID 129244310. Retrieved 28 December 2007. Various studies have shown that changes over time in spring ice-out dates can be used as indicators of climate change.... Ice-out dates have become significantly earlier in New England since the 1800s
  24. ^ Dybas, Cheryl Lyn (20 March 2006). "Early Spring Disturbing Life on Northern Rivers". The Washington Post. Retrieved 26 December 2007. Research by [USGS hydrologist Glenn] Hodgkins and USGS scientist Robert Dudley also shows changes in early-spring stream flow across eastern North America from Minnesota to Newfoundland. Rivers are gushing with snow- and ice-melt as much as 10 to 15 days sooner than they did 50 to 90 years ago, based on USGS records.
  25. ^ "Early risers". New Scientist. 167 (2241): 21. 3 June 2000. Retrieved 27 December 2007. North America's Great Lakes are reaching their spring high-water levels a month earlier than they did when records began in 1860. Levels normally rise in the spring as snow melts, but regional temperatures have been rising for the past 90 years, and winter ice cover has been shrinking.
  26. ^ Wake, Cameron (4 December 2006). "Climate Change in the Northeast: Past, Present, and Future" (PDF). Climate Change in the Hudson Valley, NY. Retrieved 27 December 2007. A particularly interesting lake ice record comes from Lake Champlain where they record the ice in date.... Of more significance is the fact that the ice has not frozen in the area of observation in 16 of the past 30 years.
  27. ^ "Why Less Winter Ice is the Pitts for State". The Detroit Free Press. 3 April 2006. Retrieved 23 December 2007. Grand Traverse Bay ... froze at least seven winters out of every 10; the rate slipped in the 1980s. In the 1990s, the bay froze only three times. So far this decade, once. Observers see that as one more sign of what some call "season creep," or evidence of global warming.
  28. ^ "Report warns of global warming increase". Portsmouth Herald. Retrieved 27 December 2007. ...Jan Pendlebury, executive director of the New Hampshire chapter of the National Environmental Trust, said... 'Global warming is forcing changes to the quintessential indicator that spring has arrived: return of the robin. Recent years have documentation that rather than flying south with other feathered friends, many populations of robins are becoming year-round residents, not only in the southern tier of the state, but as far north as Jackson.'[permanent dead link]