The article presents a study that investigates on the importance of identifying and quantifying planetary boundaries to prevent human activities in affecting environmental condition. The author states the industrial revolution and advancement in human civilization has caused the unstability of the environmental state that is less conducive for humans to live and affect their health condition. The author notes that planetary boundaries served a control variables to secure the safety of its citizen as well as protect the environment from shifting to dangerous levels. It also cites the different planetary boundaries, along with its impact on climate change and Earth system degradation

ABSTRACT. 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 (CO 2 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 O 3 concentration from pre-industrial level of 290 Dobson Units); biogeochemical nitrogen (N) cycle (limit industrial and agricultural fixation of N 2 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 km 3 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.

[1] While past strategies for agricultural water management have focused on irrigation (use of blue water), this paper demonstrates the dominance of green water in food production. A global, yet spatially disaggregated, green-blue analysis of water availability and requirement, using the LPJmL dynamic vegetation and water balance model, indicates that many countries currently assessed as severely water short are able to produce enough food for their populations if green water is considered and is managed well. The need to integrate green and blue water management is highlighted in a future scenario of water availability under climate change and population growth (HadCM2 A2). For 2050, the scenario indicates that 59% of the world population will face blue water shortage, and 36% will face green and blue water shortage. Even under climate change, good options to build water resilience exist without further expansion of cropland, particularly through management of local green water resources that reduces risks for dry spells and agricultural droughts.