Environmental Issues

The feature article A safe operating space for humanity is an introduction to the concept of scheming of our planets environment so as to maintain the so called Holocene period wherein the environment remained stable despite human interference. It is apparent that the so called environmental stability is under threat due to Industrial revolution over the years and a new era termed as Anthroprocene is now determining the global environmental changes. The Earth system could be or is already outside the Holocene state with calamitous consequences for most of the world

The author of the article Johan  Rockstrm ( Stockholm Resilience Centre) and his associates have proposed a framework for maintaining the Holocene state based on what he has termed as Planetary Boundaries these are considered as safe operating space for human race with reference to our Earth system which are associated with certain biophysical subsystems or processes. The so called subsystems have threshold values which when crossed could be disastrous for humanity.
The author further states that they have identified nine processes which in their view are important in their approach to define planetary boundaries. These nine processes include climate change, rate of biodiversity loss, interference with nitrogen and phosphorous cycle, ozone depletion, ocean acidification, global freshwater use, change in land use, chemical pollution and atmospheric aerosol loading.  According to them boundaries may be at a safe distance from threshold if they could provide the evidence for the same or they may be at dangerous level where such evidence is missing. Further for the effective quantification of planetary boundaries they have taken conservative approach due to reservations surrounding the actual position of the thresholds.

Based on their analysis the authors believe the three processes climate change, rate of biodiversity loss and nitrogen cycle has already broken their boundaries and how these could affect the earth system is demonstrated using the above three processes.

The central concept on climate change is to maintain pre-industrial rise in temperature. The climate boundary is based on two critical thresholds (i) atmospheric carbon dioxide concentrations and radiative forcing. Although the authors concur that there could be a rise of 3 C and this could lead to increase in other environmental disasters leading to still higher rise in temperature up to 6C. Secondly in the past carbon dioxide concentration was reason enough for maintenance of the polar ice caps. Thirdly evidence is mounting that some of the earth systems are moving outside Holocene period. It also appears that there is acceleration in the rate of biodiversity loss again due to human interference. The estimate of the loss is in fact at preliminary level. The manufacture of chemical fertilizer is one activity that is responsible for upsetting the nitrogen cycle since as much as 120 million tons of N2 from atmosphere is converted in reactive form which pollutes leading to eroding the earth system. The author concludes that there are gaps in the knowledge which needs to fill.

William H. Schlesinger argues that the concept of the managing the environment based on threshold appears to be a simple concept however if one waits until the damage is done
would amount to facing undesirable consequences.

According to Steve Bass the suggestion of   Rockstrm for setting a boundary of 15 per cent land use appears to dilutethe proposal of planetary boundary instead he suggests the boundary should set against soil degradation and soil loss.

The importance of the climate change implies that the atmosphere should be considered as an exhaustible resource as put forth by Myles Allen. It appears this concept does not fall in the purview of the planetary boundaries concept and as a result there is no need to contemplate as to how climate system would behave in future.

The novel concept of planetary boundary is emphasized by Mario J. Molin and he advocates the proposal should be followed by complexities of the various boundaries which could highlight the importance of reaching the thresholds of the earth-system processes. He cites the example how ozone depletion was tackled before transgressing the boundary.

One of the supporters of the concept is David Molden. The key element in the planetary boundary is the numerical values. The concept is a scientific approach that requires co-operative action on all fronts and essentially an important tool. However one needs to consider regional and local conditions which may often mask global values. In their experience on water management there are limitations at the physical level of human intervention into natural processes. He feels it is time to use the tool more effectively for consideration of planetary boundaries.

Peter Brewer appears to accept the aragonite-state at 3.44 to be quite reasonable however he cautions how these limits could be worked out. In other words a concrete plan to achieve environmental limits need to be worked out.

Cristin Samper considers the concept on three counts firstly biodiversity is more complex in terms of interaction of species and ecosystems.                                              

Secondly species extinction and global environmental changes are poorly understood. Finally single variable for biodiversity is not clear. He has suggested that biodiversity boundary should express species extinction as a probability.

In my opinion the novel concept of planetary boundaries represents a new tool in environmental studies which needs to be further authenticated by analysis of available evidence and filling important gaps in our understanding. As long as we do not transgress these boundaries we have the option of following our social and economic growth path.