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Is spring arriving earlier? Are buds bursting before their time?
A new study out of the UK, published by the Royal Society, shows that flowers are blooming 2 to 12 days earlier than they did 25 years ago. The study used 400,000 records of first blooms, and looked at over 400 species of flowers. The research showed this pattern of early blooming to be the first in recorded history. The study also showed that a 1 degree Celsius change, over a short two year period, resulted in an earlier flowering time of five days.(1) An earlier British study "Rapid Changes in Flowering Time in British Plants" (Fitter, 2002) showed that 385 plant species bloomed 4 and a half days earlier during the 1990s than the 4 decades prior.(2) And yet another study out of the UK, by the Centre for Ecology and Hydrology, found that in 2005 species were breeding on average 11.7 days earlier than in 1976.(3)
In the U.S. a study by the World Data Center for Paleoclimatology showed a 5-6 day advance toward earlier springs over a 35-year period from 1959-1993. The Northeast and Northwest states showed the most pronounced advance.(4) And more recently a study by Charles Davis, Charles Willis and others of Harvard University shows that invasive plants in Concord, Massachusetts are flowering 11 days earlier than the native species in Thoreau's woods did 100 years ago. With the unsurprising result that invasives are doing more heartily than their native neighbors. The study also notes that Concord has seen significant temperature change in the last 150 years, the mean annual temperature having increased 2.4 degrees C.(5) John Weishampel of the University of Central Florida studied the nesting times of loggerhead turtles in Florida and found they are coming ashore to lay eggs about 10 days earlier than they did just 15 years ago. He also found the water temperature in the area had increased 1.5 degrees F during that time as well.(6) Biologist David Inouye of the University of Maryland, noted that American robbins in Colorado, are arriving from their winter habitat about two weeks earlier than they did in the late 1970s.(6)
NASA research shows that this past decade was the warmest on record, and various computer models predict that into the 21st century Earth’s average temperature will rise between 1.8° and 4.0° Celsius (3.2° and 7.2° F).(7) There is little long term research in the field of "spring creep" so far here in the Americas. Although there is research work going on at Stanford that is focused on the influence of climate change upon agriculture in the U.S. and projects its potential effects into the future.(8) Professor Diffenbaugh, now at Stanford, is examining temperature changes on corn, maple syrup and grapes. In an earlier study he showed that temperatures during growing season in the wine regions of the Western States increased about 1.6 degrees Fahrenheit (0.9 Celsius) from 1948 to 2002. His climate models project U.S. wine production could decline by 81 percent by the end of this century.(9) See video below.
Temperature changes affect the length of growing seasons, blooming, leafing, fruiting, pollination, harvest, leaf coloring and frost dates. Some species migration dates are changing in correlation to temperature rise. Insects are emerging earlier and moving further north. Some of their predators have learned to hatch in sync, others have not. The out of sync species lose their food source. Increased temperatures greatly affect the geographical ranges of plants and animals. The red fox is now moving north into the arctic fox's territory.(10) As species alter location, native species are gravely threatened. And as species climb mountains to escape the heat, where will they go when they reach the top?
The word phenology is derived from a Greek word meaning "to appear, to come into view." Phenologists collect research as to dates of first occurrence. They study the seasonal timing of life cycle events in plants and animals in relationship to climate and seasonal changes. If you would like to do your part in bringing these statistics up to date, you can be a citizen-scientist right in your backyard. There are many phenology projects happening right now across the globe and they are looking for 'observers' to chronicle events in their regions.
List of phenology projects:
For worldwide listings see:
(1) www.globenews24.com BBC
(2) 'Rapid Changes in Flowering Time in British Plants'
(4) Schwartz, M.D. and J.M. Caprio, 2003,
North American First Leaf and First Bloom Lilac Phenology Data,
IGBP PAGES/World Data Center for Paleoclimatology
Data Contribution Series # 2003-078.
NOAA/NGDC Paleoclimatology Program, Boulder CO, USA
(5) 'Favorable Climate Change Response Explains Non-Native Species’ Success in
(10) "Observed Impacts of Global Climate Change in the U.S." Pew Center