Speculation is ultimately driven by scarcity. There's no purpose in speculating if you can't generate an arbitrage. Greater productivity on the part of small farmers will alleviate scarcity, driving food prices down.
Similarly, there are lots of markets that are unserved by the global food chain. How can one say that food subsidies in developed countries can affect these unserved markets? They can't sell to the developed world, and developed world food doesn't really make it there.
I spent some time in Colombia, not quite a developed or a developing nation, in mostly big cities, and even there much of the food consumption was local. Sure, bigger farmers would be able to sell at a profit to Western conglomerates, and Western food was available (at steep prices) in the large chain grocery stores.
But most people shopped at the ubiquitous small family-run groceries that served a mix of local agricultural output and mass-market, also locally-produced goods. I'd be very surprised if Western agricultural innovations weren't being employed to grow all of the great-tasting produce I ate there. Seeds are much much easier to transport than mangoes.
What is your point? You can not disprove what I said with one counterexample. Look for examples that confirm what I said.
I for example remember a documentary I saw a couple of months ago with starving people collecting single grains of rice, I think, from the streets at a market in India if I remember correctly. On the other side of the street behind a wall was a huge open space with hundreds, maybe thousands of tons of rice, bought by speculators hoping for rising prices but they didn't. Hell, even if everything worked as expected, less supply because everything got bought up causing rising prices in turn, this would be plain unethical extortion.
One other example that comes to mind is milk producers in Africa going out of business because of cheap subsidized milk powder flooding the markets. Cheap milk in exchange for now unemployed milk producers and capital leaving the country seems not such a great deal to me. And because of credits from the world bank they are not allowed to counter this development with import taxes. Free trade may be - not necessarily is - a good thing between equal parties, but between a rich, developed and powerful party on one side and a poor, underdeveloped and powerless party on the other side it becomes quite probable that it will not turn out as a win-win situation.
Similarly, there are lots of markets that are unserved by the global food chain. How can one say that food subsidies in developed countries can affect these unserved markets? They can't sell to the developed world, and developed world food doesn't really make it there.
I spent some time in Colombia, not quite a developed or a developing nation, in mostly big cities, and even there much of the food consumption was local. Sure, bigger farmers would be able to sell at a profit to Western conglomerates, and Western food was available (at steep prices) in the large chain grocery stores.
But most people shopped at the ubiquitous small family-run groceries that served a mix of local agricultural output and mass-market, also locally-produced goods. I'd be very surprised if Western agricultural innovations weren't being employed to grow all of the great-tasting produce I ate there. Seeds are much much easier to transport than mangoes.