I wish that it had taken more of an economic perspective, but the environmental science was interesting nonetheless. The thrust of the problem is that deer populations are staggeringly high and it is causing problems for biodiversity, creating more deer-vehicle crashes (which are deadly), aiding the spread of lime-disease carrying ticks to new regions, and generally annoying suburbanites.
Why has it happened? Overpopulation of herbivores is rampant all across the globe. Other examples include Canada geese, elephants, feral pigs, and gypsy moths. Our man-made landscapes provide ample food for deer, and most of the natural predators have been eliminated. The extra nitrogen added to the soil due to the herbivore feces accelerates the nitrogen cycle which is beneficial to some plants but harmful to others, reducing biodiversity.
What can we do about it? Relocation of deer is one possibility, but it is basically futile because it is stressful to the deer and 80% of them die within a year. Contraception has been largely ineffective in the wild, although it is an appealing option. Fencing works, but is expensive to implement and maintain, plus it just displaces the burden onto your neighbors. Reintroducing natural predators is another choice that wouldn't pass city council because most people aren't as tough as Bear Grylls.
The best option, according to The Nature Conservation, has been increased "culling", which is the politically correct word for hunting. This has been successful in the areas they have introduced it, although they have had strict regulations. Although some of their hunters use rifles, apparently many of them use bow and arrows, which is amazing. The speaker quoted a fact that there has never been a recorded death due to archery-based hunting of deer! That is change I can believe in.
Bottom Line: Add "learning archery" to your list of green-friendly activities, and curse the plight of overpopulated urban deer unabashedly.