We should be angry when information that must be widely available – something with real public impact – is sequestered behind a paywall. This is by way of putting some emotional steam into an important article in the eminent Scientific American, April 2010, titled Boundaries for a Healthy Planet.
Why is this article important? The issues it covers are not new, in fact, the content of this article has been under discussion (and somewhat public knowledge) for quite a long time. This publication, however, represents the clearest – most illustrative – presentation of the issues to-date. They are framed in a way that is effective, controversial, and novel. What’s novel is the framing of nine key issues as ‘boundaries’ (in the current lingo, tipping points), and in most cases defining those boundaries with measurable numbers. Each boundary represents a point of no return. Collectively, they represent the health of the planet, or with a more negative spin (in the words of the article) they represent “…nine environmental processes that could disrupt the planet’s ability to support human life.”
Here’s a brief run-down of the nine boundaries:
This is defined primarily in terms of extinction – the rate at which species disappear forever from Earth. Species have become extinct throughout the history of life, but there have been periods of greater extinction, many of them associated with ‘extinction events’ such as the impact of asteroids. We are in another period of extinction. This time it is human activity – loss of habitat, poaching, climate change – that is the primary cause.
Extinction rate (species per million per year) – Preindustrial value: 0.1-1.0, Current: > 100, Boundary: 10.
Land use, globally, is defined primarily as a matter of putting land into cultivation. The globe is rapidly approaching the point where there is no more arable land available – in fact, it may well be retreating despite all the artificial means of maintaining cropland. In a sense, this is just a bit like peak oil, where production reaches a highpoint and cannot do more. The ability to produce food is ultimately limited. Yes there is elasticity in production, aided by the wildcard of technological advances (presuming genetic modification of foodstuffs is allowed to proceed), but population growth is outstripping even optimistic scenarios. And while the last remaining arable land is converted, there is continued massive loss of habitat, and loss of species.
Percent converted to cropland – Preindustrial value: Negligible, Current: 11.7, Boundary: 15.
More than land, or oil, or food the limited resource called ‘fresh water’ is pivotal for humanity. Of course, we need fresh water to live; but our way of life, most of our economies, much of agriculture, and the viability of our local environments also depend to a large extent on the availability of fresh water. That availability is now questionable as irrigation, industrial use, and human consumption literally suck rivers dry. Climate change will redistribute the water. Overpopulation will continue to absorb it.
Rate of human consumption (in cubic kilometers per year) – Preindustrial value: 415, Current: 2400, Boundary: 4000.
Nitrogen and phosphorus cycles
The use of industrial fertilizers is upsetting the chemistry of Earth. Where nitrogen and phosphorous were relatively well distributed and even rare at the Earth’s surface, they are now more concentrated. These concentrations are in Earth’s waters and are lethal for many forms of life. The vast dead zones in the oceans are results of nitrogen and phosphorus concentrations.
Phosphorous rate of flow into oceans (million tons per year) – Preindustrial value: 1, Current: 10, Boundary: 12.
Nitrogen rate of human removal from the atmosphere (million tons per year) – Preindustrial value: 0, Current: 133, Boundary: 9.
Ozone depletion is one of the oldest environmental problems to have a wide recognition. The first warnings of damage to the ozone layer, especially over the poles, by chlorofluorocarbons (CFC) appeared during the 1970s. At that time, the ozone layer was decreasing at the rate of approximately 4% per decade. Since then, bans on CFCs and hydroflourocarbons have been put in place and monitoring continues. Humanity did something about this problem; it may be helping.
Ozone concentration (Dobson Units) – Preindustrial value: 290, Current: 283, Boundary: 276.
The good news is that the oceans are absorbing much of the world’s excessive CO2. The bad news is that the CO2 coverts to carbonic acid in the oceans. The oceans are becoming acidified, or put another way: Oceans are naturally ‘basic’ (have a pH of 8.2). The pH in the world’s oceans has already moved up to 8.0. The acidity generally causes disruption of many living things that use aragonite (a form of calcium carbonate) for shells and cell structure, for example corals, crustaceans, and phytoplankton. Vast changes in the ocean ecologies are underway with dynamics that are not fully understood.
Aragonite saturation state in surface water (Omega Units) – Preindustrial value: 3.44, Current: 2.90, Boundary: 2.75.
Climate change – global warming – is the cause célèbre of science and science opposition. By now you’d expect very few people in the literate world have not heard about the issue. Perhaps so, but it’s almost equally likely that very few people understand the scope of the issue, much less the details. How often in the thousands of hours of recent bloviation on the subject have the priorities been articulated as they are in this article? The loss of polar glaciers (sea level rise); the collapse of fresh water supplies (by overuse and climatic redistribution), and the disruption of regional weather (not rise in global temperatures, but the increasingly erratic and destructive local weather).
CO2 concentration (parts per million) – Preindustrial value: 280, Current: 387, Boundary: 350.
Chemical pollution as a major environmental problem has a long history with some real and important victories for management. However, pollution continues. In some parts of the world it is as bad as it was fifty years ago. Also, we continually add to the toxic list of pollutants; nanotechnology being only one of the latest to provide worries.
Amount emitted to or concentrated in the environment – Metric to be determined
In addition to the ozone problem there are the other forms of atmospheric pollution – mostly with particulates such as soot, chemical aerosols, and biological matter. Some of this contributes to climate change. Some of it is directly harmful pollution. Some of it is causing subtle changes in the atmosphere and the biosphere, but more research is needed.
Particulate in the atmosphere, region – Metric to be determined
I admire this effort to make the world more cognizant of its environmental problems – and doing so in the teeth of one of the most intense and heavily funded episodes of attacking science in a long time. Given the moods – and by that I mean moods ranging from completely hostile denialism to absolute indifference – discussion and dissemination of this information is going to find an uphill, if not mountainous challenge. I’m not sure if the editors of Scientific American are convinced this approach warrants a full-out effort.
It is difficult to look at this list and not be pessimistic. However, the article highlights both the possible consequences (very bad indeed) and the possible counter measures (most of which are difficult politically). There is a tone of ‘we can still do something.’ But first, we have to acknowledge the issues.
What I admire even more is the courage of the people who put this together – 30 top scientists from around the world under the coordination of the Stockholm Resilience Center – to put real (testable) numbers in front of their tipping points. These numbers are controversial even (or especially) among fellow scientists. Two boundaries are yet to be determined. Many of the others can be debated both as to the metric and the measurements. That there is a debate is part of the point. This list and its boundaries is a starting point (actually more of a consolidation point in the middle of an ongoing debate) for more discussion and much more research.
There is an argument to be made that drawing boundaries implies anything up to that point is ‘okay.’ It’s not, and the scientists involved want to make that clear. When the world gets near any of the boundaries it’s already very bad – going over them may be forever. Nevertheless, the article and much of the tone of other articles is to use boundaries as a means of clarifying the issues – giving them something relatively simple as a touch point. They don’t deal with the complexities involved with each of these issues. The approach focuses on ‘getting the point across.’ Rightly so.
There will be a storm of pooh-pooh dismissals from the denialist claque. The more thoughtful people who encounter this information will scratch their heads and wonder whether the human race is coming (progressing) or going (on the way to extinction). It is indeed a thing of wonder.
Although the articles don’t dwell on it, obviously most of the nine environmental issues are related. There is a web of causality leading mainly to human activity, which is why it’s possible to make suggestions about ways to avoid reaching the tipping points – people can (or should be able to) do something about it. That’s probably why this entire issue of Scientific American is dedicated to solutions. The cover title is, Managing Earth’s Future: Solutions for a Finite World and the issue has several articles fleshing out the main theme. Along with the rest of us, I wish every student (roughly around age 12 and up) could read at least the main article. (Sigh)
Our group’s analysis shows that three processes already exceed their boundaries: biodiversity loss, nitrogen pollution and climate change. And all the others are moving toward the thresholds. Individual limits might be fine-tuned, and others could perhaps be added in the future, but the set represents a “first order” summary of the world’s most perilous environmental conditions and provides a framework for thinking about how to manage the threats.
[Source: Scientific American]
Additional references (from the article):
Commentaries: Planetary Boundaries
Nature Reports Climate Change, Vol. 3, pp.112-119, October, 2009
Planetary Boundaries: Exploring Safe Operating Space for Humanity
John Rockstrom et al.
Ecology and Society, Vol. 14, No. 2, Article 32; 2009
Stockholm Resilience Center