system designer gas planets on planetary ann

Eventually, this led to the introduction of local or regional boundaries or constraints on what could be emitted to and extracted from the environment (e.g., chemicals that pollute airsheds or waterways) and on how much the environment could be changed by direct human modification (land-use/cover change in natural ecosystems) ( 13). This eroded local and regional environmental quality and stability, threatening to undermine the progress made through industrialization by damaging human health and degrading ecosystems. More recently, early industrial societies often used local waterways and airsheds as dumping grounds for their waste and effluent from industrial processes.

Throughout history, humanity has faced environmental constraints at local and regional levels, with some societies dealing with these challenges more effectively than others ( 11, 12).

Anthropogenic perturbation levels of four of the ES processes/features (climate change, biosphere integrity, biogeochemical flows, and land-system change) exceed the proposed PB (see the figure). The climate system is a manifestation of the amount, distribution, and net balance of energy at Earth’s surface the biosphere regulates material and energy flows in the ES and increases its resilience to abrupt and gradual change. Two of the PBs-climate change and biosphere integrity-are recognized as “core” PBs based on their fundamental importance for the ES. Although we cannot identify a single PB for novel entities (here defined as new substances, new forms of existing substances, and modified life forms that have the potential for unwanted geophysical and/or biological effects), they are included in the PB framework, given their potential to change the state of the ES. At present, only one regional boundary (south Asian monsoon) can be established for atmospheric aerosol loading. Regional-level boundaries as well as globally aggregated PBs have now been developed for biosphere integrity (earlier “biodiversity loss”), biogeochemical flows, land-system change, and freshwater use. Three of the PBs (climate change, stratospheric ozone depletion, and ocean acidification) remain essentially unchanged from the earlier analysis. The current level of anthropogenic impact on the ES, and thus the risk to the stability of the ES, is assessed by comparison with the proposed PB (see the figure).

A zone of uncertainty for each PB highlights the area of increasing risk. By combining improved scientific understanding of ES functioning with the precautionary principle, the PB framework identifies levels of anthropogenic perturbations below which the risk of destabilization of the ES is likely to remain low-a “safe operating space” for global societal development. The PB framework is based on critical processes that regulate ES functioning. There is increasing evidence that human activities are affecting ES functioning to a degree that threatens the resilience of the ES-its ability to persist in a Holocene-like state in the face of increasing human pressures and shocks. The relatively stable, 11,700-year-long Holocene epoch is the only state of the ES that we know for certain can support contemporary human societies.

System designer gas planets on planetary ann