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

We have focussed considerable attention on simplifying production using the baculovirus expression system in batch culture. In this work we show that we can achieve yields, of our model β-Galactosidase protein, using an MOI as low as 10-4 PFU/cell and a TOI of 3 x 105 cells/ml, comparable to yields achieved when infecting at much higher cell densities (TOI of 3-4 x 106 cells/ml, MOI of 2-5).

The Use of Very Low Multiplicities of Infection with the Baculovirus Expression Vector System

The major solute species concentrations in leachate from a column of retorted Rundle oil shale subject to water infiltration and subsequent unsaturated flow leaching are presented graphically. A column leachate model is developed for the chloride ion based on the full transport equations simplified by a number of assumptions. This is solved by a moving node finite element method and shown to fit experimental data. A brief summary is given of the extension of this work to modelling the other solute species.

Development of a model for leachate flow and composition from a column of spent oil shale

The Way Foward.

Batch and column leaching studies were carried out on oil shale mined from the Rundle resource, Queensland, and retorted by the Lurgi‐Ruhrgas process The kinetics of dissolution of the major leachable components in the shale (Ca, Mg, Na, K, Cl, SO4 and alkalinity) were established Material not associated with CaSO4 salts or carbonates was found to dissolve rapidly when extra‐particle mass transfer effects were minimised Ca and SO4 dissolved from CaSO4 salts at a rate which was dependent on the solution concentrations of these species It was apparent from the eluted leachate concentrations that chemical reactions and equilibria dominate the column leaching behaviour of the major components

Batch and column studies of the leaching of major inorganics from spent rundle oil shale

An economic model which incorporates the major costs associated with the operation of an industrial anaerobic reactor was developed. This model was then used to optimise the operation of a two-stage anaerobic treatment plant through manipulation of the acidification tank pH and recycle flowrate. The most effective operating strategy was to maximise the recycle flowrate and to then optimise the acidification tank pH. For this particular case study it was found that by reducing the acidification tank pH from 6.0 to 5.9 the consumption of caustic was reduced by 10 percent. Furthermore, by increasing the recycle flowrate from 72.7 to 100 m3/h the total cost of operation was reduced by 62 percent. This investigation highlights the need to develop more effective control strategies for the two-stage process and to consider the operational optimisation of the process at the design stage so as to maximise the possible savings that can be made when treating organic wastes.

Paul F. Greenfield

Papers

The Use of Very Low Multiplicities of Infection with the Baculovirus Expression Vector System

Development of a model for leachate flow and composition from a column of spent oil shale

The Way Foward.

Batch and column studies of the leaching of major inorganics from spent rundle oil shale

Cost optimal operation of an industrial two-stage high-rate anaerobic treatment plant