GPE
The GPE is the result of three important and interacting trends: (1) the continued conversion of the Earth’s biosphere into simplified produc tion ecosystems, (2) the increased intensification and dependence of these production ecosystems on human inputs, and (3) their expand ing connectivity through global markets
Increased (inter)connectivity
Increasing Scale and Speed of change
Although the drivers of this connectivity are not new (for example, trade, transport, technology and consumption), the speed and scale at which it occurs are unprecedented18. Connectivity within the GPE is underpinned by long-distance biophysical and socioeconomic teleconnections12,14. For example, irrigation and deforestation for agriculture in one location can redis tribute global evapotranspiration, thereby changing rainfall patterns and affecting terrestrial production ecosystems in other regions19. Increased CO2 emissions associated with deforestation20 also affect aquaculture and wild-capture fisheries through increased seawater temperatures and ocean acidification21. Thus, land transformation in one part of the world can have substantial effects on production ecosystems at distant locations, within and across sectors.
Global Trade Encourages Homogenization and Intensification
production ecosystems have been further simplified and intensified to produce products destined for global markets28
Leakage effects due to global trade
As long as consistent demand exists through globally distributed markets, implementation of policies to mitigate overexploitation in one place—such as protected areas or reduced quotas—may simply increase pressure elsewhere (leakage effects), with a global net decline as a result10,32
Homogenization
Concentration reduces Diversity
There are concerns that such (corporate) consolidation reinforces global homogenization of species (including genes, varieties and crops), practice and knowledge39,40.
Land Homogenization
In many areas, boreal forests have been simplified as a consequence of intensive silviculture for timber production7, tropical forests have been replaced by spatially extensive monocultures (for example, soy and oil palm plantations)43, and native Mediterranean ecosystems have been simplified by exotic pine tree plantations44. In grasslands, moderate intensification has resulted in collateral biotic homogenization across microbial, plant and animal groups, both above and below ground45. In the Amazon, rainforest bacterial communities have become homogenized as a result of land conversion to cattle pasture46 and in marine systems, rising seawater temperatures have led to the rapid homogenization of fish assemblages47.
Food Homogenization
In agriculture, national portfolios of food supplies have seen increased crop species diversity, whereas globally they have become more homogeneous in composition, illustrating a shift towards a globally standardized food supply based on a few crop types such as maize, wheat, rice and barley49.
Loss of Resilience
degrading resilience & amplifies impact of potential shocks
In the GPE, intensification and globalization have produced strong interdependencies within and among sectors. In parallel, homogeniza tion has reduced the diversity of ways in which species, people, sectors and institutions can respond to change (loss of response diversity )78 as well as their potential to functionally complement each other (loss of redundancy)16,79. This suggests that the GPE possesses features that could amplify shocks80
Suppressing Variance blinds us and erodes resilience in the long term
controlling short-term variability breeds systemic vulnerability in the long run
Increasing variability (variance) can be a signal of declining resilience in complex systems, including ecosystems and social-ecological sys tems75 but see ref. 81). Hence, intensification strategies that deliberately suppress variance may remove a useful warning of declining resilience in production ecosystems, sectors and the broader GPE82. Variance is often suppressed by controlling stress and stochastic perturbations such as grazing, fire and pest outbreaks. Such events have been proposed to increase system resilience in the long term by selecting for particular tolerant genes, species traits or practices83,84. Therefore, preventing these events may gradually erode resilience, making systems more vulnerable to disturbances that could previously be absorbed