Get to know your planetary boundaries | Guardian Sustainable Business | The Guardian
The planetary boundary concept is a new one, originating in research released In short, a planetary boundary is a limit to how much the Earth system can be .. Note that in this graph, time proceeds to the left, meaning that today is at the left. The planetary boundaries framework, first published in , introduced us to Approaches to defining a planetary boundary for biodiversity. Nine planetary boundaries have been defined that delimit the safe operating space for . Recent reviews of the relationships between species richness and.
Further research is underway to improve the availability of reliable data for use as the 'control variables' for this boundary.
The nine planetary boundaries - Stockholm Resilience Centre
These compounds can have potentially irreversible effects on living organisms and on the physical environment by affecting atmospheric processes and climate. Even when the uptake and bioaccumulation of chemical pollution is at sub-lethal levels for organisms, the effects of reduced fertility and the potential of permanent genetic damage can have severe effects on ecosystems far removed from the source of the pollution.
For example, persistent organic compounds have caused dramatic reductions in bird populations and impaired reproduction and development in marine mammals.
At present, we are unable to quantify a single chemical pollution boundary, although the risk of crossing Earth system thresholds is considered sufficiently well-defined for it to be included in the list as a priority for precautionary action and for further research.
We have reached a point at which the loss of summer polar sea-ice is almost certainly irreversible. Beyond a threshold concentration, this rising acidity makes it hard for organisms such as corals and some shellfish and plankton species to grow and survive. Compared to pre-industrial times, surface ocean acidity has already increased by 30 percent. These shifts in the hydrological system can be abrupt and irreversible.
Land system change Land is converted to human use all over the planet. Forests play a particularly important role in controlling the linked dynamics of land use and climate, and is the focus of the boundary for land system change.
Nitrogen and phosphorus flows to the biosphere and oceans The biogeochemical cycles of nitrogen and phosphorus have been radically changed by humans as a result of many industrial and agricultural processes.
The nine planetary boundaries
Nitrogen and phosphorus are both essential elements for plant growth, so fertilizer production and application is the main concern. Similarly, a relatively small proportion of phosphorus fertilizers applied to food production systems is taken up by plants; much of the phosphorus mobilized by humans also ends up in aquatic systems. As we improve our understanding of Earth processes and complex inter-relationships, these benchmarks can and will be updated Disruption of the global nitrogen cycle is one clear example: How can such ethical and economic issues be matched with a simple call to set limits?
We need to know how to live within the unusually stable conditions of our present Holocene period and not do anything that causes irreversible environmental change Their paper has profound implications for future governance systems, offering some of the 'wiring' needed to link governance of national and global economies with governance of the environment and natural resources.
The planetary boundaries concept should enable policymakers to understand more clearly that, like human rights and representative government, environmental change knows no borders.
Importantly, this novel concept highlights the risk of reaching thresholds or tipping points for non-linear or abrupt changes in Earth-system processes. As such, it can help society to reach the agreements required for dealing effectively with existing global environmental threats, such as climate change. A future worth choosing", The High-level Panel on Global Sustainability called for bold global efforts, "including launching a major global scientific initiative, to strengthen the interface between science and policy.
We must define, through science, what scientists refer to as "planetary boundaries", "environmental thresholds" and "tipping points".
This language is unacceptable to most of the developing countries as they fear that an emphasis on boundaries would place unacceptable brakes on poor countries.
For example, the UNEP Executive Director Achim Steiner states that the challenge of agriculture is to "feed a growing global population without pushing humanity's footprint beyond planetary boundaries. Red bars show temperatures above and blue bars show temperatures below the average temperature. Positive radiative forcing results in warming. From the start of the industrial revolution in tothe increase in atmospheric carbon dioxide has led to a positive radiative forcing, averaging about 1.
She puts emphasis in choosing policies that minimize costs and preserve consensus.
She favors a system of green-house gas emissions taxand emissions tradingas ways to prevent global warming. She thinks that too-ambitious objectives, like the boundary limit on CO2, may discourage such actions. Much of this new reactive nitrogen pollutes waterways and coastal zones, is emitted back to the atmosphere in changed forms, or accumulates in the terrestrial biosphere.
Most of the nitrogen and phosphorus ends up in rivers, lakes and the sea, where excess amounts stress aquatic ecosystems.
For example, fertilizer which discharges from rivers into the Gulf of Mexico has damaged shrimp fisheries because of hypoxia. He says the boundary suggested for phosphorus is not sustainable, and would exhaust the known phosphorus reserves in less than years.
Peak phosphorus Peak phosphorus is a concept to describe the point in time at which the maximum global phosphorus production rate is reached. Phosphorus is a scarce finite resource on earth and means of production other than mining are unavailable because of its non-gaseous environmental cycle.
About one quarter of the additional carbon dioxide generated by humans is dissolved in the oceans, where it forms carbonic acid. This acidity inhibits the ability of corals, shellfish and plankton to build shells and skeletons. Knock-on effects could have serious consequences for fish stocks.
A planetary boundary for biodiversity | Future Earth
This boundary is clearly interconnected with the climate change boundaries, since the concentration of carbon dioxide in the atmosphere is also the underlying control variable for the ocean acidification boundary. Human land uses include arable farmland yellow and pasture light green Across the planet, forests, wetlands and other vegetation types are being converted to agricultural and other land usesimpacting freshwater, carbon and other cycles, and reducing biodiversity.
For example, the environmental impact of 15 per cent coverage by intensively farmed cropland in large blocks will be significantly different from that of 15 per cent of land farmed in more sustainable ways, integrated into the landscape. The boundary of 15 per cent land-use change is, in practice, a premature policy guideline that dilutes the authors' overall scientific proposition. Instead, the authors might want to consider a limit on soil degradation or soil loss.
This would be a more valid and useful indicator of the state of terrestrial health. The freshwater cycle is another boundary significantly affected by climate change.