In 2016, the National Park Service put out this video on the topic of how climate change affects Washington DC's cherry blossoms.
It's part of a series of videos they've produced on how climate change affects individual national parks. It's a little over 4 minutes long and was created by the NPS Climate Change Response Program, in association with Colorado State University, and produced by Ron Bend.
Here's a transcript:
Diana Mayhew (President, National Cherry Blossom Festival):
We're here in Washington DC, during the National Cherry Blossom Festival.
Annually, the Festival attracts about 1.5 million people. It's estimated from the visitors who attend the National Cherry Blossom Festival that they put in about $150 million worth of economic impact to this area.
Neil Koch (NPS Interpretive Ranger):
This setting is extraordinarily special. For over a century, Washington DC's flowering cherry trees have heralded the beginning of spring and served as an enduring symbol of international friendship.
Dorene Ruffing (NPS Interpretive Ranger):
This is a time of year when we have people coming focused on a natural resource. These trees are greatly valued because they are a wonderful symbol of friendship between nations; the original trees were a gift from Japan in 1912.
Patrick Gonzalez (NPS Climate Change Scientist):
Now, cherry tree dates vary from year to year, but the long-term trend shows earlier and earlier blooming. Here in Washington DC, weather station measurements since 1946 show a statistically-significant temperature increase of 1.6 degrees Celsius per century, double the global rate.
In flowering trees, heat breaks winter dormancy, so earlier cherry blooming is consistent with heating caused by climate change.
Man plans and Mother Nature laughs, you know? We can do our best to plan the Festival around the median peak bloom date. We can just base our estimates off of history and science.
Phenology is the timing of life events in plants and animals. A great example is right here, the blooming of the cherry blossoms along the Tidal Basin in National Capital Parks, Washington DC.
[Early blooms can be ruined by winter storms.]
Phenology is a potential indicator of climate change.
Published research by the Smithsonian Institution shows a statistically significant advance of spring blooming of cherry trees in Washington DC by 7 days, from 1970 to 1999.1
A potential vulnerability of climate change is that it could create a mismatch in phenology. That is, a mismatch between when flowers bloom and when bees and butterflies and other pollinators mature and are ready to pollinate.
Published scientific research shows that if we don't reduce our emissions from cars, power plants, and deforestation, additional warming could advance spring blooming by another week to month by the end of the 21st century.2
With the more than 25 million visitors that we receive on the National Mall each year, the challenges are certainly great in regards to climate change, but the opportunities are great too.
It's our hope as visitors come and enjoy this wonderful area, and specifically these trees, that they will have a sense of stewardship and want to help the National Park Service protect our treasures. When visitors choose to bike or to walk or to use our recycling containers, they make a real difference in helping to reduce our greenhouse gas emissions. When people leave this area, they can carry that message with them too, so we can have a wonderful ripple effect of instilling a sense of concern for the environment and stewardship.
This Festival is deeply rooted in the mission of the Park Service. We have culture and history on display before our eyes. These are relics. These are cultural icons. And we have to do our best as visitors, as rangers, as Americans, as international guests, to make sure that we take care of our resources so that future generations can experience the same events [that] we have an opportunity to enjoy today.
[Video produced by: Climate Change Response Program, in association with Colorado State University. Ron Bend, Producer.]
The EPA also has has an interesting chart that shows the peak bloom dates gradually shifting earlier. Since the EPA website is undergoing changes and not all the old links are working, here's another copy of the graph:
You can find the original and the associated notes here.
- Abu-Asab, M.S., P.M. Peterson, S.G. Shetler, and S.S. Orli. 2001, "Earlier plant flowering in spring as a response to global warming in the Washington, DC, area," Biodiversity and Conservation, 10 (April 2001): 597-612. ↩
- Chung U, Mack L, Yun JI, Kim SH (2011) Predicting the Timing of Cherry Blossoms in Washington, DC and Mid-Atlantic States in Response to Climate Change. PLOS ONE 6(11) (November 7, 2011): e27439. doi: 10.1371/journal.pone.0027439. ↩