IMAGE framework summary/Impacts: Difference between revisions

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{{FrameworkSummaryPartTemplate
{{FrameworkSummaryPartTemplate
|PageLabel=Earth system
|PageLabel=Impacts
|Sequence=6
|Sequence=7
|Reference=Müller et al., in preparation
}}
|Description=<h2>Carbon cycle and natural vegetation</h2>
<div class="page_standard">
In IMAGE 3.0, the terrestrial carbon cycle and natural vegetation dynamics (Component Natural vegetation and carbon cycle) are modelled with [[LPJmL|LPJmL model]]. This model is used to determine productivity at grid cell level for natural ecosystems and crops on the basis of plant and crop functional types. Key inputs to determine productivity include climate conditions, soil types and assumed technology/ management levels. The model iterates with the agricultural production components as it provides input on potential productivity, while land used for agriculture and forestry is a key input. Changes in land cover, land use and climate at grid cell level have consequences for the carbon cycle, and for crop and grass productivity.
<h2>Impacts of environmental change</h2>
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Several impacts of global environmental change are calculated in IMAGE (Component [[Impacts]]). Here we describe biodiversity loss and impacts on human development.
Example: Food consumption trends lead to net expansion of agricultural land, and thus to net loss of forest (mainly tropical forests). This results in net deforestation emissions as a result of human activities. After 2050, most IMAGE scenarios expect the net anthropogenic emissions from land-use change to decline further and to result in a small net uptake (as a result of demographic trends leading to a decline in land-use for food production). However, the terrestrial vegetation as a whole, which has been a large sink during the last decades, could become a CO2 source as a result of climate change (Figure below). This could lead to a rapid increase in atmospheric CO2 concentration, given continued emissions from the energy system.
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{{DisplayFigureLeftOptimalTemplate|Baseline figure NVCC}}
===Water===
The LPJmL model used for vegetation and carbon cycle also includes a global hydrology model (Section 6.3). With this linked hydrology model, IMAGE scenarios capture future changes in irrigated areas, water availability, agricultural water demand and water stress.
Water demand for irrigated agriculture is calculated in LPJmL, based on requirements for evapotranspiration for the crop types grown on irrigated land. For other sectors (households, manufacturing, electricity and livestock), water demand is calculated based on population, economic growth, industrial value added, and electricity production as projected with IMAGE-TIMER.
Example: Projected increases in agriculture, energy and industry production, and population lead to increased water demand. Climate change also impacts the water cycle. While overall climate change is projected to lead to more precipitation, geographical patterns show changes to drier and to wetter local climates. In addition, increasing temperature leads to more evapotranspiration. As a result, the water balance improves in some regions and deteriorates in other regions, and the pattern of these changes is very uncertain. In combination with increased demand, the areas confronted with crop production losses are projected to increase significantly as shown in Figure 2.9 for a similar scenario.
Figure 2.9. Regions vulnerable to crop production losses due to shortages in irrigation water (Biemans, 2012). See also Section 6.3. 084k_img13
Nutrients
The Global Nutrient model describes the fate of nitrogen (N) and phosphorus (P) emerging from concentrated point sources, such as human settlements, and from dispersed or non-point sources, such as agricultural and natural land (Section 6.4). The nutrient surplus eventually enters coastal water bodies via rivers and lakes. Key drivers that determine nutrient emissions include agricultural production with fertiliser application, and urban and rural populations, and their sanitation systems and level of wastewater treatment. For example, the model calculates the soil nitrogen balance from the total set of inputs and outputs. Inputs include biological nitrogen fixation, atmospheric nitrogen deposition, and application of synthetic nitrogen fertiliser and animal manure. Outputs include nitrogen removal from the field by crop harvesting, grass-cutting and grazing. The nutrient outflow from the soil combined with emissions from point sources and direct atmospheric deposition determine the loading of nutrients to surface water.
 
Example: In the Rio+20 scenario, further increase in the global population and growth of agricultural production add to pressures on the nutrient cycle. While increasing wastewater treatment and improved agricultural practices mitigate some of the increased nutrient loading, these processes are insufficient to offset increased fertiliser application to sustain intense agriculture. This leads to a significant further imbalance in nitrogen and phosphorus cycles, with consequences for water quality in rivers, lakes and coastal seas.
Atmospheric composition and climate change
Calculated emissions of greenhouse gases and air pollutants are used in IMAGE to derive changes in concentrations of greenhouse gases, ozone precursors and species involved in aerosol formation on a global scale (Section 6.5). Climatic change is calculated as global mean temperature change using a slightly adapted version of the MAGICC6.0 climate model. Climatic change does not manifest uniformly over the globe. The patterns of temperature and precipitation are uncertain and differ between complex climate models. The changes in temperature and precipitation in each 0.5 x 0.5 degrees grid cell are derived from the global mean temperature using a pattern-scaling approach. The model accounts for feedback mechanisms related to changing climate, notably growth characteristics in the crop model, carbon dioxide concentrations (carbon fertilisation) and land cover (biome types).
Example: In the Rio+20 baseline, greenhouse gas emissions are projected to increase by about 60% in the 2010-2050 period. As a result, global temperature is expected to increase by around 4 °C above pre-industrial levels by 2100 without climate policy, and most likely exceeding 2 °C before 2050 (Figure 2.7). Rapid emission reductions, however, could limit temperature increase, most likely, to less than 2 °C.
 


===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]]).
<BlockQuote>
<BlockQuote>
Example: In the Rio+20 baseline, increasing energy and agricultural production levels lead to an increase of associated greenhouse gas emissions (Figure below). For air pollutants, the emission trends are more diverse. A decrease is projected in high-income countries, as emission factors drop faster than activity levels increase. However, in most developing country regions, increasing energy production is projected to be associated with more air pollution. In the policy scenarios, the target to keep global mean temperature change below 2 °C requires global greenhouse gas emissions to be reduced by about 50% in 2050. This is achieved in the model by structural changes in the energy system and by changes in emission and abatement factors.
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|Figure4 IF}}
{{DisplayFigureLeftOptimalTemplate|Policy intervention figure Land and biodiversity policies II}}
===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.
<BlockQuote>
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.
</BlockQuote>
{{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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