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Sunday, June 17, 2007

Regime Shifts in Coupled Social-Ecological Systems: An interplay of human population density, soil health and climate variability

Alex Awiti

Terrestrial and aquatic ecosystems are exposed to biotic exploitation and climate variability that often leads to changes in soil condition or nutrient loading. The state of terrestrial and aquatic ecosystems may respond in a smooth, continuous way to such changes. In some instances ecosystems may be quite inert over certain ranges of conditions, responding more strongly when conditions approach a certain critical level. A significantly different situation arises when the ecosystem response curve exhibits hysteresis or a bifurcation. This implies that, for certain environmental conditions, the ecosystem has two alternative stable states separated by an unstable equilibrium that marks the border between the basins of attraction of the states. Verifying this diagnosis is important because it implies a radically different view on management options, and on the potential effects of global change on ecosystems. Strategies to assess whether alternative stable states exist are now converging in fields as disparate as limnology and terrestrial ecology.

This paper presents evidence for the existence of alternative stable states in aquatic and terrestrial ecosystems based on recent studies on soil and vegetation interactions in the Lake Victoria Basin. A shift between alternative stable states has occurred in the Winam Gulf of Lake Victoria. Increased nutrient loading from agricultural, often exacerbated by El Nino events, industrial and municipal wastes has changed the once pristine state of clear water to high eutrophication, exemplified by high turbidity and massive algal biomass. Increases algal biomass production developed from the 1930s onwards, which parallels human-population growth, agricultural activity and El Nino episodes in the Lake Victoria Basin. Eutrophication-induced loss of deep-water oxygen started in the early 1960s, and may have contributed to the 1980s collapse of indigenous fish stocks by eliminating suitable habitat for half of the 500 + endemic deep-water cichlids.

Near infrared reflectance spectroscopy (NIRS) analysis illustrates that soil from forest-cropland chronosequence exhibit alternative stable states. Stable carbon isotope analysis a show switch in soil organic carbon input sources from tree based C3 to maize based C4 sources in ca. 30 years post forest conversion. These soils are characterized by two “spectral basins of attraction”, a reference spectral state (non-degraded) and a degraded spectral state (degraded) separated by an intermediate or transition spectral class. At an ecosystem function level, changes in infiltration, water retention and plant biomass partitioning patterns across the forest-cropland chronosequence provide further evidence of the existence of alternative soil fertility condition states. Positive feedback control between plants and limiting resources (e.g., water, nutrients) is likely to be the principle underlying soil condition shifts when natural systems are converted to low input subsistence cultivation.

Although diverse events can trigger shifts in ecosystem states, loss of resilience usually paves the way for a switch to an alternative condition state. Hence, building and maintaining resilience of desired ecosystem states is likely be the most pragmatic and effective way to manage ecosystems in the face of increasing environmental change. The challenge is to sustain a large stability domain rather than to control fluctuations. If switches between alternative condition states could be at least partially predicted, we might be able to develop novel ways of preventing catastrophic ecosystem shifts and devise evidence based systems for restoring degraded ecosystems.

Sequential or nearly simultaneous decline in land and aquatic ecosystems has the potential to deepen poverty traps in coupled social-ecological systems. Robust diagnostic surveillance of land degradation using rapid and inexpensive techniques such as NIRS can aid our understanding and enable an evidence-based approach to agricultural and environmental management.

Saturday, June 16, 2007

Global Change: Prospects for Environmentally Sustainable Futures

Alex Awiti

The most intractable challenges of our generation will be driven by what may be aptly referred to as the Anthropocene­­­­­­-a new geologic eon in which mankind has emerged as a globally significant agent capable of transforming irreversibly, the face of planet Earth. However, humankind’s debut as the preeminent protagonist of global change-actors analogous in influence to the classic roles played by erosion, volcanism and natural selection is only a recent phenomenon. This dates back several thousand years, but has accelerated greatly in scope ­and influence over the last several centuries.

The concept of global change refers to transformations in the balance of the Earth system at an unprecedented and accelerating rate. The growing demand for food, fibre, shelter, treasure and water has led to a dramatic alteration of the land surface, from natural cover to cultivated and settled lands. The carbon dioxide liberated from land use change has combined with emissions from the combustion of fossil fuels to change radiant energy balance of the atmosphere, leading to a warming of the Earth’s surface, changes in the distribution and quantity of rainfall, and a rise in the mean sea level.

Agricultural, domestic, industrial and municipal wastes are leading to high nutrient loadings in freshwater and marine water systems, accumulated toxins on land and deteriorating air, soil and water quality. Unregulated exploitation and loss of habitat for wild plants and animals has precipitated rapid declines in biodiversity; at the same time invasive species are increasing their dominance. These changes have implications such as diminishing the range of other goods and services that ecosystems provide and narrowing livelihood options, especially for poor agricultural and pastoral communities.

The challenges of global change are fundamentally different from those that our traditional research institutions and policy processes evolved to address. Early work on the limits to growth, Earth’s carrying capacity, and ecological footprints addressed important issues but generally failed to develop a dynamic, causal understanding of how complex coupled social-ecological systems respond to perturbations. More than a quarter century of serious scientific work on the resilience of ecological systems and the vulnerability of social systems is only beginning to provide a foundation for such understanding. Increasingly we are seeing the deployment of epidemiological approaches in ecological applications, especially in diagnostic surveillance of land degradation over large spatial scales.

Epidemiology is based on the premise that cause is discoverable (through a process of induction using the scientific method) by analyzing the patterns of occurrence of that phenomenon in populations. That is, a cause produces risk, which increases the rate of appearance of cases of a phenomenon among those exposed as compared with those unexposed to the cause. Understanding the cause and the mechanism through which it operates allows the design of interventions for prevention, as well as the testing of the effectiveness of those interventions.

Recent efforts to integrate social and ecological understanding have demonstrated the importance of incorporating multiple stressors, explicit pathways of exposure, the possibility of threshold responses, explicit treatment of scale, and attention to the components of adaptive capacity in frameworks for the analysis of vulnerability and resilience. Integration of social and ecological understanding has also drawn attention to the parallels between climatic and chemical “life-support systems” long discussed by Earth science researchers, the elements of livelihood security (e.g., access to and use of resources) emphasized by development practitioners, and the newer emphasis by ecologists and resource economists on ecosystem services.

The most significant idea to emerge in the eon of the Anthropocene is that of sustainability: a normative concept regarding not merely what is, but also what ought to be the human use of the Earth’s resources. The concern for using our understanding of human impacts on the Earth’s environment to help steer our use of the Earth in sustainable directions can be traced back to early work on conservation of renewable resources. A prerequisite for sustainable management is problem-driven research that utilizes these conceptual threshold-vulnerability-resilience frameworks to illuminate the kinds, rates, and magnitudes of specific disturbances beyond which the ability of society to advance human wellbeing can no longer be sustained.

Sustainable policies must be informed by the incontrovertible fact that humans are inextricably embedded in nature. As every cultivator, herdsman or fisherman knows there are limits on our behaviour and consequences for exceeding these. Although the role of government is to enable the attainment of wellbeing for the citizenry, there are principles which must assume new prominence if the goal of wellbeing is to be attained. Public policy on natural resources must be founded on the precautionary principle; look before you leap. There are nascent albeit fragile signs for the emergence of this principle. The Climate Convention, with the Kyoto Protocol, recognizes the need for responsible action on a global basis. More importantly, Millennium Development Goal 7 affirms our collective commitment to ensure environmental sustainability.

Humanity must view the future as a veritable global common. It is not the domain of any sovereign state or any private commercial interests. There is recognition of the effective limits of sovereignty in the creation of the European Union, the East African Community and the World Trade Organization. Public policy must also relentlessly demand and enforce ethics of responsibility and global accountability. The right to private property, the quest for private profit, and the sovereignty of the state do not justify ecologically destructive behaviour.

Transition to social-ecological systems that are sustainable will require courage and wise stewardship. However, the consequences of inaction are grave and undeniably catastrophic. The unvarnished truth is that our children will live in the future we bequeath them. Edmund Burke argued that the present is but an inheritance from the past that belongs, morally and legally, to the future generations as much as to the present. We have an inimitable and historic opportunity to bestow upon successive generations, a future that is sustainable and just as opposed to one of scarcity, inequity and conflict.

The Challenges facing Africa's economic renaissance

Is Africa, often dubbed the hopeless continent, finally taking off? The mood is unusually bullish. A recent report of the United Nations Economic Commission for Africa indicates that the continent achieved an annual growth rate of 5.7 percent in 2006. However, boom-and-bust cycles have stymied real economic progress in Africa.

Africa's economy has sometimes grown only to slump when commodity prices drop. Most African countries depend hugely on rain-fed agriculture and on commodities.

The Organization for Economic Cooperation and Development argues that, though the oil and metal boom is a windfall for African producers, it risks pushing the region back into a commodity corner, harming efforts to foster diversification.

Overall, Africa's economic growth is not strong enough to meet critical development goals. Growth in 45 out the 52 countries clustered in the range of 3 percent to 7 percent. The 7 percent is considered as the minimum growth rate needed to halve extreme poverty by 2015. By this measure, and at current trends, few countries would be on track to achieve the Millennium Development Goals. Current projections are that in 2015 Africa's poverty rate will remain over 38
percent; far above the 22.3 percent which was set as its Millennium Development Goals.

Africa's high population growth, deteriorating natural resource (forests, water, soil) base, a penchant for internal conflict and a notoriously variable climate (and now climate change) pose the most intractable threat to the continents ability to sustain, much less increase the current economic growth rate over the long term.

Africa's population currently growing at 2.4 percent is projected to increase from the current estimate of 800 million to 1.8 billion by 2050. This scenario presents both risks and opportunities. Africa's robust growth has only had minor backward and forward linkages with agriculture, manufacturing and services, thus limiting its contribution to reduction in unemployment and underemployment.

With little of off-farm employment opportunities, nearly 70 percent of Africa's population will depend on land for food, employment and subsistence. Under the medium population projections, per capita arable land will drop to 0.07 hectares (the benchmark land scarcity limit) in eight African countries, including Kenya. Another six African countries, including Rwanda and Malawi are projected to be only fractionally above the 0.07 hectare benchmark.

Below 0.07 ha, farmers must employ highly intensive and generally expensive agricultural methods such as use of inorganic fertilizers, pesticides and irrigation. It is not surprising that nearly 300 million people in Africa are chronically hungry. People suffering from hunger are marginalized within the economy, contributing little to output and still less to purchasing and savings. Nevertheless, the 44 percent of Africa's population aged below 14 years is a great
opportunity. If they are healthy and adequately trained, they constitute a powerful engine for domestic growth and poverty reduction.

According to the Comprehensive Africa Agriculture Development report prepared for NEPAD by FAO in 2002, soil nutrient depletion represents a significant loss of natural capital valued at an estimated US$1 billion to 3 billion per year. In the Nyando river basin of Kenya, soil losses amount to $42.7 million annually based on a conservative value of $15 per ton of soil. Losses of this magnitude will undermine the current economic upturn.

Climate change may have a graver effect on Africa than any other continent. For example, crop failure from climate change will result in a $25 billion loss while 231,661Sq.miles of arable will be ruined. Millions of people face famine and floods with relentless regularity, thanks to the El Nino/ La Nina phenomenon, increasing their vulnerability to hunger, disease and poverty. In 2005 World Food Program appealed for urgent donations of more than $150 million to prevent a food crisis in southern Africa following prolonged.

WFP warned that almost 10 million people in six countries; Zambia, Zimbabwe, Malawi, Mozambique, Lesotho and Swaziland urgently needed food aid. The El Nino phenomenon which triggers outbreaks of Rift Valley Fever causes colossal livestock fatalities in Kenya, Somalia and Tanzania. Rift valley fever is a disease which primarily affects animals, but occasionally causes disease in humans. The disease is often severe in many domesticated animals including cattle, sheep, camels and goats.

Africa is a tinderbox of fragile ecosystems and resource scarcity (land, water, pasture) lit by the spark of ethnic rivalry and bad governance. The conflict in Darfur, the Rwandan genocide of 1994 and the incessant ethnic clashes in Kenya all have roots in resource scarcity. According to the World Bank, half of the indicators point to a risk of conflict for the average country in Africa. Investment climate surveys portray Africa as a high-risk place to do business. Conflict situations lead invariably to less investment, unemployment, lower incomes, less growth and exacerbate poverty.

Enter China, Africa's most fervent investor. China sank $12 billion in aid and bought exports worth $19.2 billion in 2005. China could also be the tripwire for Africa's potential failure to attain sustainable economic growth. The high demand for African commodities reduces the incentives for economic diversification. Sudden surges in export revenues will increase the risk of currency instability due to fluctuations in commodity prices. There is also a risk for countries that have just reduced their debt burden through Highly Indebted Poor Countries Initiative and the Multilateral Debt Relief Initiative to accumulate more debt through Chinese infrastructure and export credit loans.

How pessimistic! You must be saying. The point of this is to highlight the fundamentals that set the real pace and direction of economic transformation for the continent. The key insight to be gained is that there is real work to be done by Africans to get the continent on a firm and confident trajectory of sustainable economic growth. Culturally tuned policies aimed at advancing women's health and rights must be implemented to manage the high population growth.
There must be action on environmental policy and regulation to reverse land degradation and manage the effects of climate change.

Africa states must build political institutions that generate dynamic stability. Internal security must be guaranteed to enable a stable civil environment that upholds security of persons, property, access to and equality before the law. Governments must build social cohesion, eliminate conflict and ease the paths to self betterment for their citizens through equitable access to resources, services and opportunities that will improve earnings, consumer purchasing power,
savings and investments.

The fight against HIV/AIDS must not be lost. The patterns of death in the ruling echelons now reflect the mortality patterns of the general population. According to the Institute for Democracy in South Africa mortality patterns in South Africa, Malawi, Namibia, Zambia, Tanzania and Senegal show that HIV/AIDS is a threat to democracy and governance. This will have direct impacts on planning and policy implementation.

Come on Africa, let's get to work!


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