Hello! Again, I really hope I'm writing this according to all the rules.
Okay, so. As stated by Liu Shaoqi, the Great Famine (caused largely by the Great Leap Forward) was "30% natural, 70% policy", implying it was largely man-made. In my research, however, I'd actually wager it was almost 100% man-made, due to the policies' lack of reliable economic foundations (Lysenkoism) and the tensions within the party, that hindered officials from reporting actual numbers.
I'd love to hear some arguments as to how it could have been at least affected by natural disasters. Thank you in advance!
I'm technically not supposed to be up right now, but I have some things that might be of interest to you.
In August 2005, Wei Li and Dennis Tso Yang published "The Great Leap Forward: Anatomy of a Central Planning Disaster". They made a model to test out a hypothesis that "diversion of agricultural resources and excessive procurement" led to much of the decline of grain output, a contributor to famine. Here are their results:
Our findings suggest that the most important causal factor is the diversion of resources from agriculture, which was responsible for 33 percent of the collapse of output between 1958 and 1961. Excessive procurement of grain, which decimated the physical strength of the peasantry, is the next-largest contributor, accounting for 28.3 percent of the decline in output. Bad weather did play a role, contributing to 12.9 percent of the collapse in production. The crisis thus had the marks of a perfect storm.
I highly recommend that you read that paper, since that might be the answer you're looking for with regards to possible arguments about how "it could have been at least affected by natural disasters". It's a good read.
Additionally, Yang Jisheng in his book Tombstone goes about this topic at length on p. 452. He discusses meteorological data from the years 1958 to 1961, and concludes that "there were no large-scale droughts or floods within China" and that weather "conditions were normal". Note that this is discussing weather conditions, i.e. nature. It's possible (and honestly, I'd say likely) that man-made environmental disasters contributed to the lowered grain yield.
In the scholarship that I've read about the famine, the blame is put squarely on state policies. Exactly how important certain policies were with regards to producing famine conditions differs between authors, although it's agreed upon that excessive procurement, the Exaggeration Wind, the establishment of communes (Yang would point out communal kitchens as a huge factor), and the large-scale industrial projects (e.g. massive irrigation projects) contributed to what we now know as the Great Chinese Famine. Plus, China was a net exporter of grain from 1958 to 1960, which didn't really help much.