The planetary boundaries framework defines a safe operating space for humanity based on the intrinsic biophysical processes that regulate the stability of the Earth system. Here, we revise and update the planetary boundary framework, with a focus on the underpinning biophysical science, based on targeted input from expert research communities and on more general scientific advances over the past 5 years. Several of the boundaries now have a two-tier approach, reflecting the importance of cross-scale interactions and the regional-level heterogeneity of the processes that underpin the boundaries. Two core boundaries—climate change and biosphere integrity—have been identified, each of which has the potential on its own to drive the Earth system into a new state should they be substantially and persistently transgressed.

/pdf/planetary-boundaries-guiding-human-development-on-a-changing-5gmf909etg.pdf

Planetary boundaries: Guiding human development on a changing planet

TiO2 photocatalysis and related surface phenomena

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.

/pdf/planetary-boundaries-exploring-the-safe-operating-space-for-ir5ysgjg96.pdf

Planetary boundaries: Exploring the safe operating space for humanity

Photoinduced reactivity of titanium dioxide

The global decline in estuarine and coastal ecosystems (ECEs) is affecting a number of critical benefits, or ecosystem services. We review the main ecological services across a variety of ECEs, including marshes, mangroves, nearshore coral reefs, seagrass beds, and sand beaches and dunes. Where possible, we indicate estimates of the key economic values arising from these services, and discuss how the natural variability of ECEs impacts their benefits, the synergistic relationships of ECEs across seascapes, and management implications. Although reliable valuation estimates are beginning to emerge for the key services of some ECEs, such as coral reefs, salt marshes, and mangroves, many of the important benefits of seagrass beds and sand dunes and beaches have not been assessed properly. Even for coral reefs, marshes, and mangroves, important ecological services have yet to be valued reliably, such as cross-ecosystem nutrient transfer (coral reefs), erosion control (marshes), and pollution control (mangroves). An important issue for valuing certain ECE services, such as coastal protection and habitat-fishery linkages, is that the ecological functions underlying these services vary spatially and temporally. Allowing for the connectivity between ECE habitats also may have important implications for assessing the ecological functions underlying key ecosystems services, such coastal protection, control of erosion, and habitat-fishery linkages. Finally, we conclude by suggesting an action plan for protecting and/or enhancing the immediate and longer-term values of ECE services. Because the connectivity of ECEs across land-sea gradients also influences the provision of certain ecosystem services, management of the entire seascape will be necessary to preserve such synergistic effects. Other key elements of an action plan include further ecological and economic collaborative research on valuing ECE services, improving institutional and legal frameworks for management, controlling and regulating destructive economic activities, and developing ecological restoration options.

https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1890/10-1510.1

The value of estuarine and coastal ecosystem services

A laboratory scale high rate anaerobic fluidized bed reactor, which is designed to treat a diluted molasses waste stream, has been developed; Three days after seeding, the reactor degraded 80% of the feed Total Organic Carbon (TOC) at a liquid residence time of 3 h. Step changes in reactor loading (up to 42 g molasses 1‐1day‐1) were imposed and the resulting performance monitored. It is apparent from the results that alkaline consumption is the most satisfactory indicator of reactor performance. It may be used as a measured variable for a reactor control strategy to maintain an acceptable effluent quality.

Selection of controlled variables for a high rate anaerobic reactor

Two phase flow through vertical capillaries-existence of a stratified flow pattern

Metal ions and cassava extracts stimulated growth ofRhizopus
oligosporus on a model solid substrate. A large improvement in protein content was obtained by simultaneously increasing the nitrogen content and decreasing the particle size of the substrate. No improvement occurred when these conditions were applied to cassava, however, because of the sticky consistency of the cassava after gelatinization.

Improvement of growth of Rhizopus oligosporus on a model solid substrate

This project sought to explore the impact of generic competitive strategies on corporate research and development (R&D) in Japanese technology-based companies through an extensive survey. It results in the generation of information on how Japanese firms approach the integration of R&D and corporate strategic management. Research hypotheses are empirically tested on the basis of the feedback provided by R&D managers from eighty-five leading companies in Japan. The results suggest that both cost leadership and differentiation have considerable impact on corporate R&D. However, Japanese managers particularly place great emphasis on the overall differentiation, because the strategy enables companies to satisfy the increasing demand of customers from a broad range of market segments. We also find out that Japanese managers in different types of industries and different sizes of firms tend to perceive each generic strategic alternative similarly important. Finally, we conclude that consistency with a firm's competitive strategy is considered essential for strategic R&D management.

The impact of generic competitive strategies on corporate R&D: an empirical study in Japan

The possibility of using polyurethane foam as a support for the immobilization ofZymomonas mobilis cells to carry out sucrose conversion to ethanol was investigated. Sucrose hydrolysis efficiencies of 90% and higher, volumetric reactor productivity of 20 gL−1h−1 and final ethanol concentration of 6.3% (v/v) at a dilution rate of 0.4 h−1 show the good performance of polyurethane foams for whole cell immobilization.

Paul F. Greenfield

Papers

Selection of controlled variables for a high rate anaerobic reactor

Two phase flow through vertical capillaries-existence of a stratified flow pattern

Improvement of growth of Rhizopus oligosporus on a model solid substrate

The impact of generic competitive strategies on corporate R&D: an empirical study in Japan

Ethanol production from sucrose by immobilizedZymomonas mobilis cells in polyurethane foam