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The term carrying capacity refers to the amount of ‘life’ a given place is able to support without damaging the environment.
What does it take to sustain life? In the most basic sense, our primary natural assets would include clean and adequate freshwater supplies, ample supplies of clean energy, quality soils, verdant plant life that transpires plenty of oxygen, healthy species biodiversity, and a whole lot of other things as well.
For the longest time, humans have exploited our Earth’s resources with nary a thought of the consequences. And it didn’t matter so much because there weren’t that many of us and the biosphere is remarkably resilient except in the most extreme conditions. The bad news is those extreme conditions have arrived. Over the past half century, the combination of population growth and dramatically expanded human commerce has had a devastating impact on our environment.
To live sustainably requires that it be done with minimal impact on the environment. We should be living on the interest accrued, not drawing down on the principle part of our planet’s natural assets. We have gone way beyond that. ‘Spending like a drunken sailor’ would be a good analogy to describe our cavalier attitude toward our limited natural assets. Some experts have suggested it would take as many as four Earths to provide enough water, top soil, fisheries, and forests to meet current demand over the long term. We must curb our extravagant ways and learn to do with less. Fortunately, the prospect of having to live within our planetary means may not be difficult as some might believe. It may be as simple as assigning proper economic value to our natural assets before they are exploited. Such a strategy would impose severe penalties on waste and would encourage the development of less destructive alternatives.
Many trends are positive. Trash recycling, low-flush toilets and other water conservation initiatives, efficient compact fluorescent light bulbs, improved farming methods to conserve soil, forest stewardship through green labeling; all of these things are about getting along within our means.
Author Janine Benyus’ sensitivity to biological rhythms is gracefully reflected in Biomimcry, her book about the workings of nature. Benyus writes that a living system like Earth’s, “that is far from stable, is a system ripe for change. After 3.8 billion years of research and development, failures are fossils, and what surrounds us is the secret to survival.”
Natural systems use no more than is needed, fit form to function, thrive on diversity, and curb excess from within. We humans can learn to do the same.
Challenge#3 - We Must Embrace a New Energy Paradigm That is Clean and Inexhaustible
Where energy is concerned, the need for new direction could hardly be greater. There is no longer enough oil left in the ground to meet burgeoning demand. Gas prices have already gone beyond $4 a gallon. The current economic downturn has temporarily dampened our thirst for oil, dropping the price we pay, but the trend is clear and inexorable. The price at the pump will rise again to record levels. Global climate change looms catastrophically with little time left to mount an effective response. The most important energy transition in the history of the world is already underway.
What will our energy future look like? The big players are using their money and influence to sell the idea that the coming era will be about so-called ‘clean coal’, nuclear power, and biofuels. Despite their wish to maintain control of the world’s energy markets, the oil, gas, and nuclear industries are under siege. They are not going to go away, but their place on the stage could become increasingly limited. The fabric of the world’s energy future will be woven in the image of the natural world from a diverse range of renewable energy technologies that generate electricity from sunlight, from the wind, from flowing and falling water, and from geothermal heat.
Solar PV production grew 50 percent in 2007. Solar and wind have been the fastest growing forms of energy for at least a decade. They still only account for a fraction of the total energy use in the world, but the rate of growth has consistently been between 30 and 50 percent annually, and with the costs coming down dramatically, these zero pollution technologies are becoming ever more attractive.
Wind energy can be produced profitably in the best locations for as little as 2.5 cents/kilowatt hour. That makes wind competitive with the cheapest hydroelectric and coal fired power stations, and far less costly than nuclear power. One of the criticisms of wind power is that even in the best locations, the wind is not there 100 percent of the time. This perceived lack of reliability can be overcome, according to a study by Stanford University researchers Christina Archer and Mark Jacobson, by tying regional wind farms together via transmission lines. According to Archer, “The study implies that, if interconnected wind is used on a large scale, a third or more of its energy can be used for reliable grid electric power, and the remaining intermittent portion can be used for transportation. In an earlier study, Archer and Jacobson surveyed the wind at 7,500 locations around the world. They found the commercially harvestable wind energy potential at those sites to be on the order of 72 terawatts, which is about equal to about 36,000 Hoover Dams. Harvesting just 5 percent of that total would be more than enough to meet virtually all of the world’s energy needs.
The prospect of harvesting energy from the Sun is equally exciting. On a sunny day, enough solar energy strikes the Earth in 40 minutes to meet all of our energy needs for a year. Moreover, the technology has also arrived. The average cost of solar PV has dropped from more than $100/watt in 1975 to about $4/watt in 2006. The latest, printed thin film PV technology like that developed by the San Jose based Nanosolar Company is expected to reduce the cost to as low as 30 cents/watt by as soon as 2010.
A Solar Grand Slam, an article in the January, 2008 issue of Scientific American, states that the U.S. could get nearly 70 percent of its electricity and meet 35 percent of the rest of its energy needs just from solar by 2050.
By 2020 or even sooner, newly constructed buildings, including private homes, will be designed with windows, roofs, and perhaps even siding that will have integrated solar PV generating capacity. Not only will homeowners be generating enough electric power to meet their residential needs, they will also be producing the fuel that runs their cars.
The future is going to be powered by a broad diversity of clean and abundant energy sources producing electricity. A lot of that electricity will be put to use real time. But some, perhaps a lot, will need to be stored for later use, when and where needed, Battery technology is rapidly improving and will be an important part of the answer. What cannot be accomplished effectively and efficiently via battery storage, can be processed into hydrogen as a cheap and benign energy storage medium. Why hydrogen? For one, it is the most abundant element in the universe. We can get all the hydrogen we will ever need by splitting water molecules. It is pollution free, non-toxic, and at least as safe as the fuels we’ve been using over the past hundred years. Produced in volume, it will likely end up costing less than gasoline or natural gas. It is an energy carrier whose time has arrived.
