Scientists: Human activity exceeding Earth’s limits
Posted on January 16, 2015
By Joel Achenbach January 15 at 10:14 PM
Photo: “Climate change: A severe drought plagued a third of Queensland, Australia in 2013. Destabilizing the global environment could make Earth less hospitable for humans. (David Gray/Reuters)
“At the rate things are going, the Earth in the coming decades could cease to be a “safe operating space” for human beings. That is the conclusion of a new paper published Thursday in the journal Science by 18 researchers trying to gauge the breaking points in the natural world.
“The paper contends that we have already crossed four “planetary boundaries.” They are the extinction rate; deforestation; the level of carbon dioxide in the atmosphere; and the flow of nitrogen and phosphorous (used on land as fertilizer) into the ocean.”
Keeping chickens as a hobby is very popular at the moment and many gardeners are finding space for a few chooks in their own patch. It’s been particularly trendy amongst urban gardeners, ourselves included: we have a run with 6 hens that make us self sufficient in eggs and chicken shit (the latter a vital addition to our soil’s fertility). They are also fascinating, relaxing animals to watch as they go about their chickeny business of scratching, pecking, clucking, and dust bathing. They are intelligent, social, inquisitive birds, that I’d recommend to anyone who has the space to accommodate a decent sized run and (importantly) the time to look after them.
There are plenty of magazines, books and websites offering advice on keeping hens on a small scale. One of the most active and interesting blogs is The Garden Smallholder which generally has some good advice and ideas. Back in November, however, a post about preparing a new kitchen garden caught my attention, specifically the fact that the writer’s chickens were let out onto the plot and that:
“Chickens are great at scratching and turning over soil with their enthusiastic feet, and excellent pest control too“
Let’s think about that last point, that chickens provide “excellent pest control”. It’s a statement that I’ve seen repeated many times in books and articles, and it usually doesn’t solicit any comments. But the logic behind it is that hens can differentiate between “pests” and “non-pests” in a garden, that they will gobble up the slugs and cutworms, leaving behind the worms, beetles, spiders, and other beneficial (or neutral) invertebrates. This is nonsense, of course: chickens will eat anything they find and do not differentiate between the different elements of soil biodiversity*.
Comparing patterns of terrestrial and marine defaunation helps to place human impacts on marine fauna in context and to navigate toward recovery. Defaunation began in earnest tens of thousands of years later in the oceans than it did on land. Although defaunation has been less severe in the oceans than on land, our effects on marine animals are increasing in pace and impact. Humans have caused few complete extinctions in the sea, but we are responsible for many ecological, commercial, and local extinctions. Despite our late start, humans have already powerfully changed virtually all major marine ecosystems.
Humans have profoundly decreased the abundance of both large (e.g., whales) and small (e.g., anchovies) marine fauna. Such declines can generate waves of ecological change that travel both up and down marine food webs and can alter ocean ecosystem functioning. Human harvesters have also been a major force of evolutionary change in the oceans and have reshaped the genetic structure of marine animal populations. Climate change threatens to accelerate marine defaunation over the next century. The high mobility of many marine animals offers some increased, though limited, capacity for marine species to respond to climate stress, but it also exposes many species to increased risk from other stressors. Because humans are intensely reliant on ocean ecosystems for food and other ecosystem services, we are deeply affected by all of these forecasted changes.
Three lessons emerge when comparing the marine and terrestrial defaunation experiences: (i) today’s low rates of marine extinction may be the prelude to a major extinction pulse, similar to that observed on land during the industrial revolution, as the footprint of human ocean use widens; (ii) effectively slowing ocean defaunation requires both protected areas and careful management of the intervening ocean matrix; and (iii) the terrestrial experience and current trends in ocean use suggest that habitat destruction is likely to become an increasingly dominant threat to ocean wildlife over the next 150 years.
The idea of being self-sustainable was something that my hubby was stuck on for a while. He wanted us to be able to have everything we need right at our fingertips, but the more we explored that idea we realized that it wasn’t realistic for us… yet. Maybe one day we will live on a humongous amount of land with lots of animals and all kinds of food growing in our yard, but for now we are working with a little less than one acre and I think it’s a really good start.
It’s not that we don’t like people or hate grocery stores, it would just be awesome to see where all of our food is coming from and exactly what’s going into it. We’ve just recently started buying more organic foods when we can afford to do so, and we have plans to start a vegetable garden in the spring. We aren’t experts or anything, but I would say that we’re pretty ambitious… at least the hubby is. He probably spends an hour or more everyday reading and researching [for fun] about permaculture, a design science based on nature. Basically, it goes against any kind of landscaping we’ve ever seen. Plants that we thought were weeds are actually somehow beneficial and the seemingly insignificant ones are all of a sudden very desirable. So we are in the beginning stages of making our yard into a food forest.
It’s exactly what it sounds like. A forest filled with food.
But what about the yard? Well, there will be some areas that are clear with grass or clover, but for the most part, it will be full of fruit trees, fruit shrubs and vines, herbs, and other supportive plants that ensure good soil and a healthy fungal network underground.