1. A recent study held by two Scottish universities showed that even a little bit of greenery near our homes improves our health. Green space reduces health inequities between rich and poor, maybe by encouraging exercise or reducing stress. This is especially true for heart disease and stroke, two conditions much higher among the poor.
A Columbia University study found that asthma rates among four and five year olds fell by 25% for every 343 trees per square kilometer! Given that asthma rates have gone up 50% in the last 20 years, and no one knows why for sure, this astoundingly simple preventative needs to built into urban planning. Again, the researchers aren't sure if the effect is because trees clean the air of pollution, or because trees encourage children to go outside, where they are exposed to the microbes necessary to build their immune system.
2. Not all greenery is created equal, however-- when it comes to the vegetables we eat, your mother's cauliflower is not the same as the cauliflower you eat-- it has 40% less vitamin C than it did in 1975, broccoli has 50% less calcium and watercress has lost 88% of its iron-- and this is as was measured in 2001. You can read about the discovery in the 2001 Le Magazine. And the larger the vegetable, the lower the nutritional value overall. A 2007 Organic Center report shows that
Vegetables pumped full of water from fertilizers and then grown in nutritionally depleted soil are nowhere near as good for you as vegetables grown in your backyard in a raised bed filled with your own compost from backyard greenery.
3. Finally, while we are all becoming more familiar with the necessity of greenery for the survival of the planet in terms of global warming, consider the number of wars caused by scarcity of resources, in particular water and food. Geoff Lawton at the Permaculture Research Institute of Australia has been developing permaculture projects across the globe. This short video will give you a sense of what's possible if we are wiling.
Image from Inspired Economies.