Heric, that's a spectacularly shallow and blinkered assessment by any reckoning, yet even that article has to concede that the US has great swathes of land that would actually benefit from increased population. (Population density in the US, in relation to resources and habitable land is exceptionally low.) Here's a revealing extract:

If immigrants tended to come from cultures that shared a green-orientation with us, like Germany and Japan, or if they tended to be well-educated like the typical Sierra Club member, they'd pose less of a threat to the environment. However, most immigrants today tend to be poorly educated, and originating in societies that put little emphasis on conservation.

Latin Americans have shown a positive disregard for environmentalism as evidenced by their tendency toward littering and driving smog-belching old junkers.

Instead of spouting ignorant generalisations of that sort, the author should acknowledge that the American nation, collectively, is the biggest anti-conservation factor on earth. The notion that the US has any kind of "green-orientation" to share with Germany, Japan or anywhere else, is just laughable.