Why Are Japan’s Cherry Blossom Trees Blooming in Fall?

The buds that are flourishing now in Japan won’t open again in the spring, but fortunately, the proportion of blossoms that have opened in recent days is relatively small. So, Wada tells NHK, the unseasonal bloom is not likely to affect the splendor of the cherry blossoms next spring.

Stress-induced-flowering is well known - for example, https://www.canr.msu.edu/news/why_are_my_apples_blooming_in_...

In what appears to be the source article: https://www3.nhk.or.jp/nhkworld/en/news/20181018_04/ the arborist clarifies, "this year trees have lost their leaves, stripped off by violent winds or left to wither from salt exposure."

Assuming it's because of global warming simply because it's an unusual environmental occurrence seems to be a popular pattern. Several news sources extrapolate to that as well, along with references to the pattern of earlier spring blooming in DC and Kyoto (more likely attributable to the urban heat island effect, as it started well before CO2-induced warming would have been significant).

I’m assuming you’re trying to claim this is not related to global warming (“ it has happened before”).

Global warming is a large scale and long term problem, and the first thing you would expect is an increase in frequency of previously uncommon events - take warm weather: historically there may have been a few year where the temp got to X degrees, from an average of Y degrees. But now the average Temperature has increased by a small amount. That shifts the entire normal curve of temperatures up. So now instead of X degrees being the 99th percentile (say) it becomes the 90th. The wonders of normal curves and statistics ensures that as small changes accrue the current extremes will rapidly become more common - a 1% increase in average temperature (random Number here) results in a frequency shift of more than 1% for the extremes.

Then we get to the localized vs global issue. Global warming in an average increase in temperature across the world. The world is big, and so there will always be area that are substantially higher or lower temperature than other places, but by virtue of the above statistics over time the high temperature pockets will become larger and more common. The high temperature pockets and the increased energy in the atmosphere increase movement of the atmosphere around the globe - so yes you may also get occasional pockets of uncommon low temperature. that is likely cause by uncommonly “high” temperatures in the cold parts of the world pushing the higher than average cold air into new locations. Over time the average temperature of the cold areas will become “warm”.

Finally, many biological and physical behaviors are purely a function of very specific temperatures. A lot of the biological behaviors (in plants especially) are direct products of physical laws - gas and fluid expansion being most common. Plenty of amphibians have gender determined entirely by temperature - something like 23.4c being the exact cutoff. Water freezes/thaws at exactly 0c - it doesn’t matter how small the difference is.

I have lived in the Northeast for a total of 19 years and can not remember a year as bright and spectacular as 2018.

And this is 100% correct. And, it has happened before. The world has had warming and cooling cycles for as long as there has been earth. The idea that all of this is a “new” thing isn’t supported by evidence.