ABC News ran a story this week reporting on the early bloom of the cherry blossom trees in Washington, D.C., attributing the early bloom to climate change. This is false. Although the cherry blossom bloom has arrived earlier in recent years, the cause is the population increase in D.C, and development that has caused a localized heat biases from the urban heat island (UHI) effect, causing fewer late season freezes and higher average nighttime temperatures in the area. The same is true for Tokyo.
The reporter in ABC News item, “Cherry blossoms blooming earlier due to climate change,” says that “Washington’s iconic cherry blossoms are approaching peak bloom, and it’s happening earlier due to human-amplified climate change.” This change, while not catastrophic is disrupting travel to see the blooms, causing travelers who come to D.C. to see the bloom annually to have to plan for earlier vacations.
Similar stories have run in past years around this time of year over the past decade, including in the Washington Post in 2023, and the BBC describing a similar situation in Tokyo in 2024.
It may be true that cherry blossoms are reaching peak bloom days earlier in recent years than they have in past decades, but if so, population growth and the associated UHI effect are to blame, not a modest rise in global average temperatures. The UHI effect is a well established phenomena in which as a location experiences population growth and densification, the development associated with comes with artificial sources of heat, such as, surfaces like concrete, asphalt, buildings, engines, furnaces, boilers, and air conditioner exhausts. These heat sources absorb sunlight and heat during the day only to release it slowly at night, which tends to raise the average temperatures for nighttime, biasing the overall average temperature for any location so effected.
Concerning Tokyo, as explained in the February 2024 Climate Fact check posted at Climate Realism, even as Tokyo’s unbiased average annual temperature has declined since 1997, the impact of the UHI effect there has been to artificially boost the average temperature there by 5.4℉ over the past century, far above the average rise measured for the island nation as a whole. This bias results in earlier spring like conditions with higher nighttime lows, resulting in the early bloom.
Research published in the peer reviewed journals Geophysical Research Letters and Environmental Pollution explain that UHI effect could shift blooming dates by several days to weeks in large metropolitan areas when compared to trees and flowering plants in nearby rural locations.
Another peer reviewed study published in the Journal Climate specifically discussed the UHI signature Washington D.C. The figure below from that study shows maps of the UHI signature of Washington, D.C. in the morning, afternoon, and at night.
The maps above show that the UHI dominates the downtown core, where Washington, D.C.’s cherry trees are located along the tidal basin. So it isn’t surprising that the cherry trees react accordingly and bloom earlier as the UHI signature has grown over time.
Measured temperatures in Washington, D.C. have risen more than the nationwide average, largely as a result of population growth and the resultant UHI over the past century. Washington, D.C.’s population has grown by more than 331 percent since 1950, associated with a huge amount of development. The National Park Service has been tracking the peak cherry blossom bloom since the early 1920s and its data, displayed on the Environmental Protection Agency’s website, shows that the annual peak bloom has shifted earlier as population has grown there. (See the graph, below)
ABC News ignores the research and data which strongly suggests that the UHI is wholly responsible for earlier spring peak cherry blossom blooms, due to fewer late season frosts and warmer average nighttime temperatures. But, of course, this is in line with narrative that the mainstream media pushes concerning climate change, that it causes everything bad. The facts may not support this, but then the facts don’t inspire a compelling news story, which is all that ABC and other outlets seem to really care about — generating public interest, attention, clicks, and ad sales, rather than reporting the truth.
H. Sterling Burnett, Ph.D., is the Director of the Arthur B. Robinson Center on Climate and Environmental Policy and the managing editor of Environment & Climate News. In addition to directing The Heartland Institute’s Arthur B. Robinson Center on Climate and Environmental Policy, Burnett puts Environment & Climate News together, is the editor of Heartland’s Climate Change Weekly email, and the host of the Environment & Climate News Podcast.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
I suggest ABC is just sucking up to Democrats, who have a True Believer faction on climate change, and a perhaps larger faction who finds it useful in justifying their vote buying schemes, ahem, “social justice”.
More likely ABC has given up being the torch of truth as it became a profit center for a large corporation.
Profit centers are required to generate revenue, not merely cover costs.
UHI is a form of anthropogenic climate change. Just unrelated to CO2.
Micro climate, that is….
True, now if only more people can understand that, especially climate “scientists”.
Rud ==> Yes, ALL climate is local to some geographical area. I have more than one climate region on my own property — a spot that is subject to last frost date and earlier first killing frost than the rest of the property by up to a week or ten days.
That’s local climate.
I’m not even sure if it is scientifically correct to say “Global Climate” at all.
I suspect hot air from Congress might have something to do with it as well.
With that hot air they aim to cover up decades of rampant fraud waste and abuse
ABC is owned by Disney, the same folks who present scripted cartoons and movies to children as if they were reality.
Remember, if you wish hard enough, Tinkerbell will come back.
“Tinkerbell will come back.”
As a mincing black male trans…. Still dressed in a tu-tu !
Similar to how they destroyed Doctor Who.
The Disney way. !
And the Snow White movie will be a success
Doonman ==> Disney Entertainment now owns National Geographic magazine also…and it is apparent in its content which now resembles a blending of the old Popular Science and Popular Mechanics magazines.
Very nice Sterling.
I read a similar AP cherry blossom story in my local paper. Total rubbish.
A couple of days ago there was talk of high temp records being set here in Colorado. They were wrong by it being 10F cooler than the record.
Hell, yesterday, there was an inch of snow in Woodstock, VT
This morning 30 F.
The heat is on
“The UHI effect is a well established phenomena”
Phenomenon. Phenomena is plural. God, why can’t people get these things right…
As someone who has struggled with grammar police my whole life, and who just had lunch here with a college roommate whose whole career was private high school English teacher, let me split the difference as a proper lawyer would. (I am a lawyer, but was never proper.)
UHI is a phenomenon concerning DC cherry blossoms, but a phenomena when also applied equally to Tokyo cherry blossoms.
Because most people aren’t nitpickers. Nobody likes a scold.
Yeah, but I like accuracy. If we can’t get the little things right, then there’s not a lot of hope with tackling bigger things.
You mean like you just did?
Because they don’t speak Latin
Phenomenons would be proper English
Museums, instead of musea
Aquariums, instead of aquaria
While “phenomenons” is casually accepted, all major dictionaries state the plural is phenomena. Ergo, it is not “proper English.”
Since we are talking science, the correct Latin is much more applicable than social/common ignorance.
I thought “phenomena” was something they sometimes put in perfumes?
Humor – a difficult concept.
— Lt. Saavik
I have absolutely no objections to cherry season being extended.
Can we get to say – 9 months a year?
Problem is, the blossoms only come once a year.
There’s probably a crude response to that comment, but this is a family science site.
It’s a family site? I thought it’s mostly hard bitten, old, white, arch conservative red necks!
/s 🙂
You peeked!
Or, since it is cherry blossoms, you peaked!
/h
Last time I “peaked” it was 1972 at a rock concert. 🙂
LOL
Like government employees?
But countless other species will blossom throughout the warm season.
Simple observation in my home area of Texas shows this heat island effect very well. For the past 20 yrs I’ve lived in the country 1 county west of Ft. Worth, but work in a suburb between Ft. Worth and Dallas near the center of the heat island. Growing season at my house is about a month shorter with our first frost typically 2 weeks earlier in the fall and last frost about 2 weeks later in the spring. In summer the difference in temp is not usually more than a couple of degrees, but when cold, calm air settles in during winter we are sometimes as much as 7 or 8 degrees colder than in the city only 50 miles away, though typically it’s more like 3 or 4 degrees. Our lawn will be brown and dead but there will still be green lawns in the city in December. Early flowering herbaceous plants in spring will be fully mature and blooming in the city while at our house the same species are barely sprouted from the ground. I can also often see the temp change in my car thermometer getting warmer going into town and cooler as I get back home.
And pray tell, regardless of its cause, what is the “problem” with an earlier spring as signified by earlier cherry blossoms? Omigosh, the world is coming to an end!!!!
These doofuses in the climate industry are just crazy – warm is GOOD, cold is BAD. Other than a handful of ski resort operators, what people want the Earth to be colder than it is? I mean, really!
People have to schedule their vacations to come see these trees at an earlier date! Oh the trauma!
Regardless of why they’re blossoming early- all should rejoice that winter is over! Whining over early cherry tree blossoming is nuts.
Whining over an early end to winter is also nuts!
Which groundhog predicted an early spring? I do not recall, but I do know a lot of people were hoping for an early end to winter.
I kinda was hoping for more winter. I had to mow about a month earlier this year. I am completely traumatized.
So sue Exxon. 🙂
I should, since they’ve never sent me my Big Oil Shill checks.
“So it isn’t surprising that the cherry trees react accordingly and bloom earlier as the UHI signature has grown over time.
Measured temperatures in Washington, D.C. have risen more than the nationwide average, largely as a result of population growth and the resultant UHI over the past century. Washington, D.C.’s population has grown by more than 331 percent since 1950, associated with a huge amount of development.”
This point is too much like the argument over CO2, ie, “CO2 has risen X% for Y # of years, ‘associated with’ emissions growth, so therefore the temperature has risen because of CO2 emissions.”
There was no robust association made here in this article. From looking at the cherry bloom date plot, it is more likely following the ocean temperature evolution with signs of ENSO influence.
No robust data. Copy that.
Tall buildings change the effective surface area for the solid-gas interface and do so substantially.
That alone defines an increase in absorption of thermal energy during the day for release at night and thermal energy drives temperature.
Couple that with increased transportation vehicles that emit thermal energy, and increased energy consumption (lights, heating, cooling, computers, etc.) that also emits thermal energy concentrated in an area and you get temperature effects that vary widely from the equivalent land area in a rural or less densely populated area.
So, no. The point is not similar to the CO2 falsehood.
If one had the time, one could assess accurately how much asphalt, concrete, glass, steel, car fuel consumption, electricity consumption and calculate a reasonable number or at least an order of magnitude number WITHOUT THE USE OF COMPUTER MODELS.
ENSO influence. Another correlation is causation argument.
You’ve taken the exact path as the post author, by stating things as though they are important without showing any actual scientific relationship, in other words, hand-waving.
Why don’t you show why UHI matters to the Cherry peak bloom date data? Then you might have a case against my point, but not until. For instance, you or Sterling could show how the DC area UHI supporting timeseries compares to the EPA Cherry bloom data plot.
In the collage I put together today on this topic, below, the biggest surprise I found was no one here has caught that the EPA’s plot is actually inverted from their .csv data file !!!
The Peak Bloom 10yr centered average indicates much larger departures from average from 1942-1955-1974 that are not explainable by invoking UHI effects.
In addition, it is clear the ocean temperature surrounding the DC area is important, and the ENSO has an influence. During El Niño there are more clouds, which are apparently delaying the peak bloom date, and vice versa for many La Niña periods, though not exact, more than enough supporting evidence to make my point.
Excuse me but my point was that a comparison to the misconception that CO2 drives the climate is not accurate to UHI. ENSO may be related, but just eyeballing a couple of curves, which the poster did is a correlation – causation flaw.
Of course ENSO has an effect, but that was not the thrust of my counter point.
We all need to agree at the outset, CO2 is a micro actor regarding GW
Once that is out of the way, we can better concentrate on other factors, such as El Niños and water vapor and urban heat archipelago.
The urban, deforested area from Southern Maine to Virginia is an heat archipelago, one giant, several-hundred-mile-long heat island
Much of Europe is an urban heat island
All that W/S money uglified the countryside, killed fisheries, tourism, viewsheds, etc.
But the climate is not any different than 30 years ago, even though, atmosphere CO2 increased from 280 ppm in 1850 to 420 ppm in 2025, 50% in 175 years.
During that time, world surface temps increased by about 1.5 C, only about 0.5 C can be attributed to CO2, with the rest from:
1) Long-term cycles, such as coming out of the Little Ice Age,
2) Earth surface changes, due to increased agriculture, deforestation, especially in the Tropics, etc.
3) Urban heat islands, such as about 700 miles from north of Portland, Maine, to south of Norfolk, Virginia, forested in 1850, now covered with heat-absorbing human detritus. Japan, China, India, Europe has similar heat islands
.
BTW, the 1850 temp measurements were only in a few locations and mostly inaccurate. The 1979-to-present temp measurements (46 years) cover most of the earth surface and are more accurate, due to NASA satellites.
The dates of peak cherry blossoms mirror general global average surface temperature in thjat we can see the Global Cooling Years (1945-198x) and the gentle rise since, bringing the blossoms on earlier by about a week.
Can anyone supply a graph of March and April daily average temperatures in the DC Mall for the same period?
Why cannot the press ensure that what they write reflects scientific realism? Net Zero is seen today to be clear nonsense science. Governments – incl the UK and the EU – know it and are backing off. Not one forecast based on it or any of its underlying aspects has ever come to pass. Yet we still pay under the Paris Agreement. Why? Clear international face saving is still with us.