The 100th Meridian Shifting East

[AnTonY]

In the US, the 100th meridian has traditionally represented the dividing line between the moist east and the arid west. But according to research done by scientists at Columbia University, using data collected since 1980, that line of of longitude may have effectively shifted eastward due to climate change, to a position closer to the 98th meridian. And it may continue to "move east" during the coming years. 

The map below looks to represent precipitation minus PET. The posted article contains links to the actual research that this conclusion came from. Overall, this can have huge impact on palm growers/gardeners throughout the Eastern US. And certainly, other countries may very well be experiencing these types of climate shifts too.

Personally, I'd say that the effects are highly variable depending on how specifically this "increasing aridity" comes about. Thus, it's something that just has to be seen to in the coming years.

http://blogs.ei.columbia.edu/2018/04/11/the-100th-meridian-where-the-great-plains-used-to-begin-now-moving-east/

 

[tropicbreeze]

We have a line in Australia called "Goyder's Line", runs more or less east-west and is the demarcation between higher rainfall/arable land to the south and low rainfall/marginal land to the north. The line was calculated back in the mid 1800's but over the past several years scientists have been saying it's moving south due to climate change. Here's a link to an old news article about it.

Goyder's Line

 

[Austinpalm]

Wow!  Not much room for Goyder's Line to move south.

[tropicbreeze]

And there's a massive multi-million dollar wine industry just below the Goyder Line. It might put a new meaning to "dry wines".

 

[Josue Diaz]

Interesting article. I think, though, that the article is talking about the continental dry/wet climate divide shifting eastward (closer to the 98th meridian,) not that the meridian is actually shifting. The latitude/longitude lines are arbitrary lines and aren't bound to shift unless the scientific community shifts all latitude and longitude lines, they're simply units of measurement. 

[AnTonY]

@Josue Diaz, yes, the climate divide shift is what I meant, not the actual lines shifting. Which is why I used the term "effectively" in the original post.

@tropicbreeze, the Goyder's line looks specific to southern Australia, since the tropical monsoon areas of the continent are technically north of the line. But, it can also be said that the "100th meridian" may be specific to the eastern US, as there are clearly some moist areas (Pacific Northwest) west of the line.

Edited April 25, 2018 by AnTonY

[Silas_Sancona]

Was interesting reading the article when it came out since there is also some research out suggesting that the heart of Tornado Alley may also be shifting east. Makes sense since a shift east in the overall transition zone would also tend to shift where a dry line develops there during storm season. 

That said, I was shocked to see what a "minor" drought can do to the landscape when living in KS years ago, let alone what happened in Texas more recently. 

[AnTonY]

@Silas_Sancona, I will say that while the net effect would be as if the meridian "moved east," the changes probably aren't coming from "drier air masses moving farther east." Since the study gauged greater "aridity" in much of the country based on greater year-round evapotranspiration, the dryness would really be more from the poleward retreat of the mean westerly storm track, warming up temps, while reducing snow/cold. This would fit in the tropical shift theory that's been floating around, which is exactly what's happening with Australia's Goyder line.

So, I could see the Great Plains/Midwest drying out heavily. Much of inland and northern Texas will also dry out, including areas of the Piney Woods. However, assuming that these shifts also occur to the tropical wind belts, southern/coastal Texas may retain some moisture, or even get wetter, albeit with different seasonal concentrations (i.e. summer concentration vs greater year-round spread).

[Silas_Sancona]

@AnTonY

Agree on your thoughts regarding both potential shifts.  I mean, I myself would think that as the general position of the Jet stream shifts further and further north over time, it would make sense that both the drier " in between" belt and the more tropical belts would also shift up ( in the northern Hemi.)

Two things I keep waiting to see: extensive / very detailed research into what might happen with the summer monsoon pattern over the SW. US and S. TX, and what may happen with E Pac. Hurricane activity overall..
 Following on what id said above, id think AZ, NM, and W.TX would slide into a more favored position instead of generally being near the edge, and that S. Tx also would come under a more summer precipitation-favored position. Id also assume ( however off i might be) that areas north of Baja would see more effects from passing tropical systems in a "shifted" favored area of storm development there than occurs at this time.. No, such shifts to receiving more rainfall during the summer wouldn't completely offset any large potential deficits in both winter rainfall /snowfall  but I am skeptical of grotesquely "gloom and doom" scenarios, even if I can see the negative aspects of loosing valuable water resources.. 

The other thing I hope people understand is that even if a dramatic shift were to occur / continue evolving across Tx and the Plains.. it doesn't mean there wouldn't still be especially wet years.. Just as there are still going to be cold winters in a warming world..  Yes the traditional "Bread Basket" may shift north/ north east but the region isn't going to become the new Sahara either. Plenty of room to adjust and work with new crops / plants for the garden. 

-Nathan

 

[AnTonY]

@Silas_Sancona

The "doom and gloom" tone comes from laymen in the media reporting what they can pick of from the research. Which isn't much.

Though to be fair, it doesn't help that the research is often overly broad, both in the models they use (that often miss out on localized atmospheric features), as yearly-breakdown. Even if a place were to dry out, any changes in precipitation pattern could be huge in regards to the true result. Terminology doesn't help either. When you use a term like "aridity," the most often associated context is that barren desert. But a look at details shows that the circumstance is gauged by annual rainfall and PET. In that sense, even a place like Tampa would be marked as drier than Boston, due to similar annual rain totals, but warmer temps year-round: indeed, even the map I posted shows an area of brown in the Florida Peninsula in contrast with much of the East in green. But we all know the lushness that is present in Florida's landscape.

Edited April 26, 2018 by AnTonY