Tag Archives: global change

Planet Under Pressure: Understanding the Anthropocene







Peatlands as complex adaptive systems

Shifting states. (Left) Hummock-hollow pattern at Rygmossen, a small raised bog near Uppsala, Sweden. (Right) "Ladder" system of ridges and pools, Inverewe Bogs, Scotland. Persistent environmental change, such as a long-term increase in climate wetness, can trigger a shift from one such peatland type to another.


In a Perspective in Science, Nancy Dise reviews how the response of peatlands to global change will be complex (doi:10.1126/science.1174268). She writes:

Research from a variety of areas and approaches is converging upon the concept of peatlands as complex adaptive systems: self-regulating to some degree, but capable of rapid change and reorganization in response to internal developmental changes or to external forcing (4). It has long been known, for instance, that the surface of a peatland can rise and fall, sometimes dramatically, in response to rainfall or mild drought, while maintaining a fairly constant water level relative to the surface. This “Mooratmung” (“bog-breathing”) is related to the sponge-like nature of Sphagnum, which can adsorb water and trap gases. Recent studies have shown that the carbon balance of peatlands can in turn be surprisingly resilient to perturbations, even fairly severe ones. For example, subjecting peat cores (5) or a peatland field site (6) to a water table drawdown similar to a prolonged drought initially led to a respiration-driven loss of soil carbon. But both carbon loss and subsidence (6) lowered the peat surface, decreasing its height above the water table, and effectively shifted the system back toward its starting state. Conversely, a rising water table stimulated growth of Sphagnum and other vegetation, which increased carbon accumulation, raised the surface of the peat and, in effect, lowered the local water table (5). Thus, an environmental perturbation may trigger an initial gain or loss of carbon, but recovery in the direction of the initial state can moderate the impact.

Long-term global changes—particularly warming, drought, and elevated nitrogen deposition—are likely to ultimately induce shifts in some existing peat-forming areas to new ecosystems such as grassland or shrubland (10, 11), and the increase in biomass from vascular plants could in part compensate for carbon losses from soil oxidation during the transition. However, even if some net carbon accumulation returns, the gains are short-lived: The key peatland quality of slowly removing and storing carbon for hundreds or thousands of years is lost.

Considering peatlands as complex adaptive systems characterized by quasistable equilibrium states—resilient to change at some level of perturbation but shifting to new states at higher levels of disturbance—provides a meaningful framework for understanding and modeling their response to environmental change. Ignoring the strong feedbacks inherent in peatlands may lead to substantial under- or overestimates of their response to global change. The challenge is to forecast both the future environmental conditions that peatlands will experience and the internal feedbacks and state changes that may be triggered by these conditions. To meet this challenge it is vital to continue and expand long-term monitoring networks to characterize the present, paleo-environment research to reconstruct the past, and manipulation experiments in the field and laboratory to build our understanding of these unique and valuable ecosystems.

Global change and missing institutions

In  Science Policy Forum, Brian Walker and others have a policy forum in Looming Global-Scale Failures and Missing Institutions, in which they argue that the the global order of nation-state’s has improved the well-being of many people at the cost of global resilience, and that building global resilience requires more interaction among existing global institutions, as well as new institutions, to help construct and maintain a global-scale social contract.  They write:


…Of special importance are rules that apply universally, such as the peremptory, or jus cogens, norms proscribing activities like genocide or torture. Failure to stop genocide in Rwanda spurred efforts to establish a new “responsibility to protect” humanitarian norm (12). As threats to sustainability increase, norms for behavior toward the global environment are also likely to become part of the jus cogens set.

The responsibility to protect rests in the first instance with the state having sovereignty over its population. Only in the event that the state is unable or unwilling to protect its people are other states obligated to intervene. The challenge is not just to declare the principle but to ensure its acceptance and enforcement. Acceptance is needed for legitimacy, and enforcement will depend on whether states are willing to make the necessary sacrifices. If the responsibility to protect is to apply to the environment as well, these same challenges will need to be overcome. We use three examples to illustrate how institutional development might proceed.

Climate change. International climate agreements must be designed to align national and global interests and curb free-riding. Borrowing from the WTO architecture, the linkage between trade and the environment could be incorporated within a new climate treaty to enforce emission limits for trade-sensitive sectors. New global standards could establish a climate-friendly framework with supporting payments, e.g., for technology transfer, to encourage developing country participation. In this context, trade restrictions applied to non-participants would be legitimate and credible, because participating parties would not want nonparties to have trade advantages.

Coevolution of institutions offers a pathway to further progress. Recently, the Montreal Protocol strengthened its controls on hydrochlorofluorocarbons (HCFCs), manufacture of which produces hydrofluorocarbons (HFCs) as a by-product. HFCs do not affect ozone and are not controlled under the Montreal Protocol. However, they are greenhouse gases (GHGs), controlled under the Kyoto Protocol. The Montreal Protocol should now either be amended to control HFCs directly or else a new agreement, styled after the Montreal Protocol, should be developed under the Framework Convention to control HFCs.

High-seas fisheries. The Code of Conduct for Responsible Fisheries, which was adopted by the U.N. Food and Agriculture Organization in 1995 was a positive step, but because adherence is voluntary, it has had little effect. Another approach would be to develop a norm, akin to the responsibility to protect (12), requiring all states responsible for managing a fishery to intercede when a state fails to fulfill its obligations. Credible enforcement is a challenge, but efforts by major powers to enforce a U.N. General Assembly ban on large-scale drift-net fishing offers hope that an emerging norm can be enforced (13).

Drug resistance. Addressing drug resistance demands global standards. The International Health Regulations (IHRs) are an international legal instrument that is binding on 194 countries, including all the member states of the World Health Organization. It currently establishes minimum standards for infectious disease surveillance, but could be amended to promote standards for drug use. For example, monotherapy treatments for malaria are cheaper but more prone to encourage resistance in mosquitoes than combination therapy drugs. Their use should be limited in favor of the more expensive combination therapy drugs. One approach to global action would be an amendment to the IHRs that obligated all member countries to collective action to promote combination therapies, supported by global subsidies, and to discourage, or even prohibit, monotherapies (14).

Intensive agriculture’s ecological surprises








