IMAGE framework summary/Impacts: Difference between revisions

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|Description=<h2>Drivers (population, economy, policies, technology)</h2>
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Key model inputs are descriptions of the future development of so-called direct and indirect drivers of global environmental change. These include population, economic development, lifestyle, policies and technology change ([[Scenario drivers]] Component). Most drivers such as technology change are input in various IMAGE components (see [[Scenario_drivers/Model_drivers#Table of drivers|Table of drivers]]). To ensure that exogenous assumptions made about these factors are consistent, brief scenario storylines are formulated on how the future may unfold and are used to derive internally consistent assumptions for main driving forces. For example, yield assumptions in the agricultural economy model and performance of solar power production in the energy model depend on a more generic description of the rate of technology change. Population and economic development can be provided as quantitative outputs from external sources or models, and dealt with quantitatively as exogenous model drivers. Other drivers mostly concern assumptions in other parts of IMAGE.  
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<h2>Impacts of environmental change</h2>
Several impacts of global environmental change are calculated in IMAGE (Component [[Impacts]]). Here we describe biodiversity loss and impacts on human development.


For population, IMAGE uses exogenous assumptions, such as total population per region, household size and urbanisation rate. However, GISMO population projections can also be used, which enable feedback on environmental factors, such as air pollution and undernourishment on population growth to be taken into account (Component [[Human development]]). Exogenous assumptions are used for economic variables, such as GDP. In most studies, economic projections are developed by macroeconomic models based on the scenario storylines. Sector-specific economic indicators and household consumption can be derived directly from such models, and complemented by income categories, reflecting the GINI coefficient, a measure of disparity in income distribution.
===Biodiversity loss ===
Biodiversity loss is assessed by the impact model GLOBIO (Component [[Terrestrial biodiversity]]) as calculated changes in mean species abundance ({{abbrTemplate|MSA}}). The MSA indicator maps the effect of direct and indirect drivers of biodiversity loss provided by IMAGE, including climate, land-use change, ecosystem fragmentation, expansion of infrastructure, disturbance of habitats, and acid and reactive nitrogen deposition. Their compound effect on biodiversity is computed with the [[GLOBIO model|GLOBIO3 model]] for terrestrial ecosystems. As IMAGE and GLOBIO3 models are spatially explicit, the impacts on MSA can be analysed on a grid by region, main biome and pressure factor. A similar model has been developed to map biodiversity in fresh water (Component [[Aquatic biodiversity]]).
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Example: In the Rio+20 study ([[PBL, 2012]]), global population is based on the UN medium projection and grows to about 9 billion people in 2050, the increase occurring mostly in developing countries (Figure below). The economic projection of the Rio+20 study shows that developing countries increasingly dominate the world economy in terms of total GDP (Figure below). For the OECD countries, the baseline scenario assumes a long-term economic growth rate of 1 to 2% per year over the whole scenario period. In the short term, per capita growth rates in Asia and Latin America are much higher, but converge gradually to a long-term growth rate of around 2% per year. In contrast, Africa shows a later peak in economic growth.  
Example: A further decline in biodiversity is projected in the Rio+20 baseline at an almost historical rate. While historically habitat loss has been the key driver of biodiversity loss, more important pressures in the coming decades are projected to be climate change, forestry and infrastructure (the figure below).
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{{DisplayFigureLeftOptimalTemplate|Figure1 IF}}
{{DisplayFigureLeftOptimalTemplate|Policy intervention figure Land and biodiversity policies II}}
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===Human development===
Changes in the global environmental impact on human development in many ways. Via the link to the [[GISMO model]], the IMAGE framework describes impacts on human health, and the achievement of human development goals such as the Millennium Development Goals (MDGs; see Component [[Human development]]). The health module describes the burden of disease per gender and age, including communicable diseases, and also health impacts of air pollution and undernourishment, and interactions between these factors.
 
The model puts the impacts of global environmental change in perspective of other factors determining human health. For instance, hunger is defined as the proportion of the population with food consumption below the minimum dietary energy requirement. The model determined hunger on the basis of distribution of food intake over individuals calculated on the mean food availability per capita (from other parts of IMAGE), and a coefficient of variation.
Water supply levels and sanitation are modelled separately for urban and rural populations by applying an empirical regression model, depending on per capita GDP, urbanisation rate and population density.
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Example: With regard to global hunger, the Rio+20 scenario shows improvement compared to the last few decades. This improvement is a consequence of rapid income growth in low-income regions and levelling off of population growth (the figure below). The baseline scenario also shows a decline in population without access to safe drinking water, sanitation and modern energy. In all cases, the improvement is too slow compared to policy ambitions.
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{{DisplayFigureLeftOptimalTemplate|Figure6 IMAGE framework summary}}
===Other impacts===
Other impacts calculated in the IMAGE framework using separate impact models include flood risks (Component [[Flood risks]]), land degradation (Component [[Land degradation]]) and ecosystem services (Component [[Ecosystem services]]). Many impacts of global environmental change are an integral part of the modules in the Human system and the Earth system, such as water stress and climate change impact on crop yields (Component [[Impacts]]).
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Latest revision as of 15:48, 21 October 2021

Parts of IMAGE framework summary

  1. Introduction page
  2. Introduction model description
  3. Drivers
  4. The Human system
  5. Interaction Human - Earth system
  6. Earth system
  7. Impacts
  8. Policy issues
  9. Data, uncertainty and limitations
  10. Overview of references
Projects/Applications
Relevant overviews
Key publications


Impacts of environmental change

Several impacts of global environmental change are calculated in IMAGE (Component Impacts). Here we describe biodiversity loss and impacts on human development.

Biodiversity loss

Biodiversity loss is assessed by the impact model GLOBIO (Component Terrestrial biodiversity) as calculated changes in mean species abundance (MSA). The MSA indicator maps the effect of direct and indirect drivers of biodiversity loss provided by IMAGE, including climate, land-use change, ecosystem fragmentation, expansion of infrastructure, disturbance of habitats, and acid and reactive nitrogen deposition. Their compound effect on biodiversity is computed with the GLOBIO3 model for terrestrial ecosystems. As IMAGE and GLOBIO3 models are spatially explicit, the impacts on MSA can be analysed on a grid by region, main biome and pressure factor. A similar model has been developed to map biodiversity in fresh water (Component Aquatic biodiversity).

Example: A further decline in biodiversity is projected in the Rio+20 baseline at an almost historical rate. While historically habitat loss has been the key driver of biodiversity loss, more important pressures in the coming decades are projected to be climate change, forestry and infrastructure (the figure below).


Global biodiversity under baseline and sustainability scenarios to prevent biodiversity loss
Biodiversity is projected to decline further in the baseline scenario (left). Various measures in the demand system, the production system and in land-use regulation contribute to reducing biodiversity loss in the sustainability scenarios (right).

Human development

Changes in the global environmental impact on human development in many ways. Via the link to the GISMO model, the IMAGE framework describes impacts on human health, and the achievement of human development goals such as the Millennium Development Goals (MDGs; see Component Human development). The health module describes the burden of disease per gender and age, including communicable diseases, and also health impacts of air pollution and undernourishment, and interactions between these factors.

The model puts the impacts of global environmental change in perspective of other factors determining human health. For instance, hunger is defined as the proportion of the population with food consumption below the minimum dietary energy requirement. The model determined hunger on the basis of distribution of food intake over individuals calculated on the mean food availability per capita (from other parts of IMAGE), and a coefficient of variation. Water supply levels and sanitation are modelled separately for urban and rural populations by applying an empirical regression model, depending on per capita GDP, urbanisation rate and population density.

Example: With regard to global hunger, the Rio+20 scenario shows improvement compared to the last few decades. This improvement is a consequence of rapid income growth in low-income regions and levelling off of population growth (the figure below). The baseline scenario also shows a decline in population without access to safe drinking water, sanitation and modern energy. In all cases, the improvement is too slow compared to policy ambitions.


Human development indicators in baseline scenario
Human development indicators

Other impacts

Other impacts calculated in the IMAGE framework using separate impact models include flood risks (Component Flood risks), land degradation (Component Land degradation) and ecosystem services (Component Ecosystem services). Many impacts of global environmental change are an integral part of the modules in the Human system and the Earth system, such as water stress and climate change impact on crop yields (Component Impacts).

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