In the last post I mentioned that human society was ‘having adverse effects’ on the biosphere and the climate. Sounds like a cheap/ ‘science class’ statement...? Here are a few facts on human activity.
One of the most striking realities is the fact we have domesticated almost all the land that can be, to some extent (cities, agriculture, pastures etc...). This graph tells us that about 35% of total land area has been domesticated.
Source for this graph and others in this post: IGBP ‘Global Change and the Earth System’
This map makes it easier to visualize the space we are talking about:
In brown are the areas in which at least 30% of the landscape is cultivated. You might think there is a lot of ‘untouched space’? Well obviously the Sahara is immense and useless to us both because it is infertile and there’s no rainforest providing services like creating oxygen or no wetlands to purify water. Australia is also in large proportion a great desert in the southern hemisphere, Siberia and the very north of America are extremely cold, not allowing for great human activity or biodiversity. Unfortunately we are starting to see some brown in the rainforest regions (Amazon and central Africa).
So you can see how much of the land surface, of the entire planet, we are somehow controlling. We must also remember that for these spaces to be used, we need water; hence we are pumping water from rivers, water tables, lakes etc. Pumps can be very traditional (even artisanal) or mostly powered by fossil fuels (-> CO2). Also in a lot of places, chemicals such as pesticides and fertilizers are used, which end up in water tables. We are talking non-stop activity here, at all these places on the map, everyday, during every passing year. As a result, forests are cut down, fossil water (non regenerating water tables) are used up, over-exploitation of land causes desertification, exports of food (vegetables and meat, both containing water) means that “across the planet, 1 major river in 10 no longer flows to the sea for several months a year”. This is large scale, multi-effect activity.
Another major thing; fish stocks – the amount of fish left in the oceans. This graph shows that nearly 80% of fisheries are fully exploited today.
Global fishing has gone from 18 million to 100 million of metric tons/year since 1950. This is industrial fishing, happening so fast that fish don’t have the time to reproduce. A good representation of that can be found in sport fishing. Here is a photo of the ‘trophy fish’ at the end of a recent fishing day somewhere in Florida:
Here are the ‘trophy fish’ from the same place, same boat, in the 1950s:
Yeah... they were huge
These photos are taken from a TED talk by Jeremy Jackson, highly recommended if you can spare 20minutes to the guy:
http://www.ted.com/talks/jeremy_jackson.html. He also explains the many implications of ocean problems caused by over-fishing, pollution and climate change.
An interesting figure; fish is the staple diet of 1 in 5 humans on Earth.
Next! We can talk about rain-forest destruction. Rainforest absorb a lot of CO2 – destruction of rainforest is also a cause of CO2 concentration increase.
Biodiversity loss; species are disappearing at 1000 times the natural rate. As said in the previous post, evolution since the beginnings of life has lead to a biodiversity in which each species has a role in maintaining the equilibrium of living conditions on the planet. Biodiversity is lost by habitat destruction, land use, toxic leaks, emissions, over-exploitation and more...
Back to the CO2 and climate change; remember all these water pumps around the world? Burning fossil fuels for electricity to power our industries, agriculture, cities, homes, ships (fishing, tankers, cargos, leisure..!!), planes... 24/7, never-resting, all around our blue beauty = Greenhouse gases emissions.
I mentioned 385ppm of CO2 in the previous post as the current level. This is equivalent to 790 gigatonnes of carbon in the atmosphere (actual quantity). As we keep burning fossil fuels, it keeps increasing; an increase nowhere near stopping for the moment. “If we wished to stabilise CO2 emissions at a level double that which existed before the industrial revolution (widely considered the threshold of dangerous change), we would have to limit all future human emissions to around 600 gigatonnes. Just over half of this would stay in the atmosphere, raising CO2 levels to around 1100 gigatonnes, or 550ppm, by 2100. This, incidentally, would be a tough budget for humanity to abide by, for if we use fossil fuels for another century, that equates to a budget of 6 gigatonnes per year. Compare this with the average of 13.3 gigatonnes of CO2 that accumulated each year throughout the 1990s (half of this from burning fossil fuel), and the projection that the human population is set to increase mid-century to 9 billion, and you can see the problem” (Tim Flannery – The Weather Makers). Another interesting figure is that 70% of all people alive today will still be alive in 2050...
Scientific evidence suggests that ‘the last time polar regions were significantly warmer than present for an extended period (about 125,000 years ago), reductions in polar Ice volume let to 4 to 6 meters of sea level rise (IPCC report 2007). I let you imagine what happens to cities like New York will do it that case, there are so many of them (I used to think the artificial islands in Japan – e.g. for airports – were clever...). An important point here, I’ve talked about AVERAGE temperature rise so far. At the poles, changes are much bigger (I will post more detailed numbers on a separate page soon). Other than sea level rise, the atmosphere affects everything on the biosphere because it is in contact with it, and the climate governs the season’s behaviour (so to speak), along with droughts, floods etc...
Now, anyone doing some hard thinking yet?? Those are SOME of the facts. I summarised and left out A LOT so that I can have a “bloggable” text. When I think of all this, I wonder what we are collectively thinking... we are simply wrecking the place faster than it can regenerate itself, in a long term manner and not realising the inter-connectedness of things. This means that we have less and less opportunity for people to ‘get by’!! = UNSUSTAINABILITY
SUSTAINABILITY:
Many researchers have come up with definitions so far:
Fuwa defines biophysical sustainability as preserving or improving the integrity of the life supporting systems on the earth. Hence the biosphere systems that provide clean air, fresh water, food (plants) etc... this is a more ‘nature’ oriented definition.
Solow defines sustainability as a matter of preserving the production capacity for a long future. Here it makes sense to interpret ‘production’ on different levels: as above, nature’s production of clean air (etc... fish for example!), and also our production of social ties, services, and other creations allowing us all to live AT LEAST a decent life with dignity (that's my take on it).
So where do we – YOU & ME – fit in this grim picture? The scale of it all may be overwhelming yet we are still doing well on a personal level (if you have power for your computer, access to internet and can read this you’re doing pretty well to me!). I said I’d elaborate social aspects in this post but with rectify my aim and talk about it later, along with sustainability principles.
As it is my first attempt to communicate sustainability content to an audience as broad as possible, I’ll appreciate your feedback. Is it too complicated, not precise enough, fuzzy etc?? Also there is continuity between the posts, some content may become clearer once you’ve read Part I. Many thanks in advance for your input!
