Friday, August 24, 2007

Dust bowl weather...

... but no dust storms.

I have many disagreements with the standards and practices of early 21st Century large-scale agriculture. But I am happy to admit that there have also been some significant advances in the last 50 years in agricultural practices. The drought we are having now may or may not have some contribution from global climate change; only another few decades of climate data will sort this out. But it has reached a magnitude where it clearly belongs among the great droughts of the Dust Bowl Cycle. A Special Weather Statement from the Nashville NWS this morning rightfully reminds their readership that extreme heat waves and droughts are a well-known part of natural variability of our climate here. They list other periods that have had summers of comparable brutality to what we are experiencing now: the 1930s, 1950s, 1980s, and now the mid 2000-aughts (this is actually our third consecutive year of summer drought; this year is however far more extreme than the previous two). Anybody else detect a periodicity there? The 1930s and, to a lesser extent, the 1950s were the great dust bowl eras; even in the early 1980s I remember a few episodes of dust clouds that travelled across multiple States. So far in the Aughts, this hasn't been happening. I'm happy to credit the lack of a Dust Bowl this decade to the half-century-plus of work by the Soil Conservation Service, Extention Agencies, Ag Colleges, and every one else who has developed and taught soil conserving tillage and management practices.

The skies may be scorching and desicated, but at least they are blue, not red!


At 11:06 AM, Blogger Ivorybill Septic said...

Bill, do some reading up on the recently recognized Atlantic Multidecadal Oscillation. It appears we may be in for a multidecadal period of increased drought in the midwest and increased hurricane activity in the Atlantic.

At 11:46 AM, Blogger Bill Pulliam said...

The periodicities in the "dust bowl" cycle and the Atlantic hurricane season were recognized statistically long ago, actually. But there seems to be more at play that just the AMO; for example, the drought cycle gives an impression of peaking twice per every single cycle of the AMO (1930s and 1950s, 1980s and 2000-aughts); indeed the near dust-bowl conditions of the 1980s occured during a negative phase of the AMO. There are ENSO affects as well, plus doubtless other regional and global scale long-term processes.

Regardless, I think it is fair to say that we are in fact in the midst of a peak in both the drought and Atlantic hurricane cycles, not just facing one in the future.


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