Identifying and quantifying planetary boundaries that must not be transgressed could help prevent human activities from causing unacceptable environmental change, argue Johan Rockstrom and colleagues.

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A safe operating space for humanity

:The carbon sink capacity of the world’s agricultural and degraded soils is 50 to 66% of the historic carbon loss of 42 to 78 gigatons of carbon. The rate of soil organic carbon sequestration with adoption of recommended technologies depends on soil texture and structure, rainfall, temperature, farming system, and soil management. Strategies to increase the soil carbon pool include soil restoration and woodland regeneration, no-till farming, cover crops, nutrient management, manuring and sludge application, improved grazing, water conservation and harvesting, efficient irrigation, agroforestry practices, and growing energy crops on spare lands. An increase of 1 ton of soil carbon pool of degraded cropland soils may increase crop yield by 20 to 40 kilograms per hectare (kg/ha) for wheat, 10 to 20 kg/ha for maize, and 0.5 to 1 kg/ha for cowpeas. As well as enhancing food security, carbon sequestration has the potential to offset fossilfuel emissions by 0.4 to 1.2 gigatons of carbon per year, or 5 to 15% of the global fossil-fuel emissions.

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Soil carbon sequestration impacts on global climate change and food security.

The resilience perspective is increasingly used as an approach for understanding the dynamics of social–ecological systems. This article presents the origin of the resilience perspective and provides an overview of its development to date. With roots in one branch of ecology and the discovery of multiple basins of attraction in ecosystems in the 1960–1970s, it inspired social and environmental scientists to challenge the dominant stable equilibrium view. The resilience approach emphasizes non-linear dynamics, thresholds, uncertainty and surprise, how periods of gradual change interplay with periods of rapid change and how such dynamics interact across temporal and spatial scales. The history was dominated by empirical observations of ecosystem dynamics interpreted in mathematical models, developing into the adaptive management approach for responding to ecosystem change. Serious attempts to integrate the social dimension is currently taking place in resilience work reflected in the large numbers of sciences involved in explorative studies and new discoveries of linked social–ecological systems. Recent advances include understanding of social processes like, social learning and social memory, mental models and knowledge–system integration, visioning and scenario building, leadership, agents and actor groups, social networks, institutional and organizational inertia and change, adaptive capacity, transformability and systems of adaptive governance that allow for management of essential ecosystem services.

Resilience: the emergence of a perspective for social-ecological systems analyses

Anthropogenic pressures on the Earth System have reached a scale where abrupt global environmental change can no longer be excluded. We propose a new approach to global sustainability in which we define planetary boundaries within which we expect that humanity can operate safely. Transgressing one or more planetary boundaries may be deleterious or even catastrophic due to the risk of crossing thresholds that will trigger non-linear, abrupt environmental change within continental- to planetary-scale systems. We have identified nine planetary boundaries and, drawing upon current scientific understanding, we propose quantifications for seven of them. These seven are climate change (CO2 concentration in the atmosphere <350 ppm and/or a maximum change of +1 W m-2 in radiative forcing); ocean acidification (mean surface seawater saturation state with respect to aragonite ≥ 80% of pre-industrial levels); stratospheric ozone (<5% reduction in O3 concentration from pre-industrial level of 290 Dobson Units); biogeochemical nitrogen (N) cycle (limit industrial and agricultural fixation of N2 to 35 Tg N yr-1) and phosphorus (P) cycle (annual P inflow to oceans not to exceed 10 times the natural background weathering of P); global freshwater use (<4000 km3 yr-1 of consumptive use of runoff resources); land system change (<15% of the ice-free land surface under cropland); and the rate at which biological diversity is lost (annual rate of <10 extinctions per million species). The two additional planetary boundaries for which we have not yet been able to determine a boundary level are chemical pollution and atmospheric aerosol loading. We estimate that humanity has already transgressed three planetary boundaries: for climate change, rate of biodiversity loss, and changes to the global nitrogen cycle. Planetary boundaries are interdependent, because transgressing one may both shift the position of other boundaries or cause them to be transgressed. The social impacts of transgressing boundaries will be a function of the social-ecological resilience of the affected societies. Our proposed boundaries are rough, first estimates only, surrounded by large uncertainties and knowledge gaps. Filling these gaps will require major advancements in Earth System and resilience science. The proposed concept of "planetary boundaries" lays the groundwork for shifting our approach to governance and management, away from the essentially sectoral analyses of limits to growth aimed at minimizing negative externalities, toward the estimation of the safe space for human development. Planetary boundaries define, as it were, the boundaries of the "planetary playing field" for humanity if we want to be sure of avoiding major human-induced environmental change on a global scale.

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Planetary boundaries: Exploring the safe operating space for humanity

▪ Abstract We explore the social dimension that enables adaptive ecosystem-based management. The review concentrates on experiences of adaptive governance of social-ecological systems during periods of abrupt change (crisis) and investigates social sources of renewal and reorganization. Such governance connects individuals, organizations, agencies, and institutions at multiple organizational levels. Key persons provide leadership, trust, vision, meaning, and they help transform management organizations toward a learning environment. Adaptive governance systems often self-organize as social networks with teams and actor groups that draw on various knowledge systems and experiences for the development of a common understanding and policies. The emergence of “bridging organizations” seem to lower the costs of collaboration and conflict resolution, and enabling legislation and governmental policies can support self-organization while framing creativity for adaptive comanagement efforts. A resilient social-eco...

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Adaptive governance of social-ecological systems

Charles David Keeling passed away unexpectedly on 20 June 2005, at the age of 77, after suffering a heart attack. Dave Keeling’s name will always be associated with the time series record of atmospheric carbon dioxide at Mauna Loa, which is often called the ‘Keeling curve’. It has achieved iconic status as the foremost record of human influence on the earth’s climate. He made the first and most important contribution to the now universal acceptance that atmospheric CO2 is building up globally because of human activities, and beyond that, to the developing recognition that our species has become a force for change on earth of geological proportions. Dave Keeling was the first to make very accurate measurements of atmospheric CO2, starting in 1955. Before he announced his early results, it had appeared, largely from measurements in Scandinavia by a wet chemical method and published in Tellus, that CO2 varied regionally from 250 to more than 350 ppm. If correct, that would have made it difficult to detect a slowly increasing trend. There was also no convincing evidence of an annual cycle in the Scandinavian data. As one of the outcomes of the International Geophysical Year, Keeling was able to start in 1958 continuous measurements of CO2 at the Mauna Loa Observatory, at an altitude of 3400 m, a site that he guessed might be representative for much of the globe. His method of choice of the measurements was infrared absorption, backed by a system of very careful calibrations and independent flask samples. He had already observed in air samples he had taken along the west coast of North America and in samples of oceanic air that there appeared to be a global background concentration with a quite narrow range. After the start of the Mauna Loa measurements, he later confessed to some anxiety, when the measured mole fraction was going down in July. Could there be a problem with the instrument? By the second year, he was confident that he had seen the annual cycle of carbon dioxide produced by photosynthesis and respiration, as well as an increase from one year to the next. No statistics were necessary to pull a tenuous signal out of the noise; it was there in plain view for all to see. Due to the high quality of the observations, other discoveries followed, such as the gradient in CO2 mole fraction from north to south and its development over time, the relationship of the growth rate of CO2 to the El Nino–Southern Oscillation, the changing seasonal cycle of CO2, relationships between the 13C/12C isotopic ratio and CO2 itself, and major features of the pattern of the partial pressure of CO2 in surface ocean waters. What makes Dave Keeling’s measurements so convincing are his close attention to measurement protocol in order to avoid biases, his careful and continuing calibration procedures, and his deployment of independent methods, such as flask samples analyzed at the Scripps Institution of Oceanography that could be compared with the instrument operating on Mauna Loa. His measurements have

In memory of Charles David Keeling

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S1355770X98230257

Environmental scares, science and media

Askö 1997: Food Production, Population Growth, and the Environment

The process that has led to an agreement on a Framework Climate Convention, FCCC, represents a complex and interesting example of cooperation between on one hand the world scientific community in the field of environmental sciences, and on the other the countries of the world through the Intergovernmental Panel on Climate Change, IPCC. The IPCC was formed in 1988 by the United Nations Environment Programme, UNEP, and the World Meteorological Organization, WMO, to take the lead within the UN-structure in the pursuit of the climate change issue. When the International Negotiating Committee, INC, was formed in 1991, and accordingly negotiations for a Framework Convention on Climate Change began, the scene was somewhat modified. A more clear separation between a fact-finding process such as that of the IPCC and the political process on negotiating agreements on actions became possible.

Bert Bolin

Papers

In memory of Charles David Keeling

Environmental scares, science and media

Askö 1997: Food Production, Population Growth, and the Environment

International Scientific Networks

Carl-Gustaf Rossby