Meteorologist Chris go...
Because I just finished writing an 11-page paper on the subject, muffin top.
The 1930s drought was forced by a cool equatorial Pacific (persistent La Niรฑa) and a warm North Atlantic. It was indeed amplified by positive land surface feedbacks from bare soil exposure and dust loading from wind erosion, but both were primarily caused by natural devegetation of the landscape from dry conditions.
Only ~30% of the Great Plains was ever plowed where deep-rooted perennial prairie grasses were replaced with shallow-rooted annual crops like wheat. Agriculture was overall an insignificant factor in the incidence and continental scale of the drought and complementary heat extremes. Dust loading actually reduced incoming shortwave radiation by over 5 W mโปยฒ, which lowered daily maximum temperatures a few degrees.
The term โDust Bowlโ actually refers to a relatively small region in the Texas and Oklahoma panhandles, southwestern Kansas, and eastern Colorado that were affected by dust storms. But the term is now incorrectly used to describe the entire drought.
And, how do I confidently know most of it was natural?
Because there have been many droughts like it (or worse) in the past, including two during the 19th century. Care to explain how farmer Johnsonโs tilling fits in there, Sparky?