I really like this project, its fun and love the design. However I find the environmental argument incredibly flawed, especially the 900 million umbrella figure

I really like this project, its fun and love the design. However I find the environmental argument incredibly flawed, especially the 900 million umbrella figure. If we use Trapicks figure of 33 million umbrellas sold in the US and assume that the US is representative of the general population of the world then only 600 million umbrellas are sold each year. I suspect its far less, I would expect the US to consume more than the average number of umbrellas. I think this wildly outrageous number is damaging what otherwise is a really cool project!