Why in Asia more than in other parts of the world? Mitigation of weather-related risks and oportunities should apply to any farmer with enough sophistication.
Maybe the comment was more about the agricultural economy. Most farmers have been and continue to be small-scale farmers (a few acres?), and since there are a lot more people in Asia, I'd expect a lot more farmers. I'm guessing that climate changes would hit 1000 people each with 2-acre farms in Asia differently than it would the pocketbook of 1 person with a 2000 acre farm in America that grows crops that get partially subsidized by the US govt. The role the govt plays (or doesn't, for example, b/c of excessive corruption), is also a factor.