Análisis de la Competencia

Sectors

The carbon sector has two major feedbacks producing radiative forcing that leads to increase in temperature. In climate sector atmospheric CO2 is translated in the radiative

forcing with the forcing equation. The other sources of radiative forcing are computed from other gases: methane, nitrous oxide, chlorofluorocarbons and other Montreal protocol gases. All the forcings are then added together to feed into the climate sector as an input variable.

where is for total forcing in W m-2; , ,and stand for radiative forcing from carbon-dioxide, chlorofluorocarbon and nitrous oxide respectively. represents Montreal Protocol and other gases; while CA and CA0 denote the current and the initial

The climate sector plays a very important role in the ANEMI model version 2. Its product and temperature change impact almost all the sectors of the model. The population, food production, hydrologic cycle, land-use, water demand, and water quality sectors are connected with the climate sector through the global temperature. In many cases the temperature rise may have more negative than positive effects. Increased temperature could boost the evaporation from a water body and increase the water-stress by lowering the stock of available water. However, there is a chance that if the temperature change takes place, some countries of the northern hemisphere (Canada included) could be able to expand their agricultural areas further north. Granted, the increase in temperature could potentially increase the irrigation demand, which may then act as a constraint for agricultural land expansion.

For estimating the impact of the current trend in climate change on the energy-economic sector, the climate damage function is introduced. The climate damage function assumes a relationship between economic damage and the extent of warming. According to Nordhaus and Boyer (2000), the specific relationship between global temperature increase and income loss is expressed by damage function in quadratic form:

(3.89)

where is the damage from climate change, as a fraction of output and atmospheric temperature increase (in degree Celsius) over year 1900 level, and are parameters of the damage function.

The increase in temperature affects the global hydrologic cycle by changing the intensity of evaporation, precipitation pattern, starting day of snow melt, and so on. The simplest way of introducing the effect of temperature change in the hydrologic cycle is by defining a fixed temperature multiplier. In many cases, this linear relationship may not be valid because of non-linear feedback effects. The current understanding of Arctic ice melt provides an interesting example of this. Light covered surfaces such as ice and snow reflect the incoming solar radiation back into outer space, while dark covered surfaces such as oceans and land absorb the incoming radiation, which increases the temperature and contributes to further warming. The higher global temperature triggers the melting of Arctic sea-ice and as the sea-ice melts there is less ice to reflect the incoming solar radiation and more open ocean to absorb the solar energy. This absorbed energy triggers a positive feedback that warms the ocean further causing more ice to melt faster. Huntington (2006) stated that global precipitation is energy limited rather than moisture limited, and so precipitation is expected to rise by 3.4% per 1 surface temperature increase. This leads to the following functional relationship, which is extracted from Davies and Simonovic (2008):

where is the temperature multiplier, which takes its value from , the precipitation multiplier is measured in Kelvin, which denotes the change in surface temperature; is a fixed value of 3.4% K-1.

This simple relationship is used to establish feedback links between climate, water use, water demand, and evaporation calculation. To model the effects of climate change on irrigation water requirements, the ―per hectare water withdrawals‖ and ―per hectare water consumption‖ are multiplied by the same ‗temperature multiplier‘. The carbon sector of the ANEMI model version 2 deals with the total carbon balance at the global scale, even though a significant portion of carbon is produced in the energy-economy sector.

The population sector is linked to the land-use sector in the same way as Davies (2007), which followed the approach of Goudriaan and Ketner (1984). For further details readers are directed to Davies and Simonovic (2008).

The emissions from the energy-economy sector are directly imported and added to the carbon sector. Carbon emissions from each type of energy source are calculated based on energy consumption and carbon content. The following equation computes the CO2

emissions in 106 tons C.

where = annual production in 106 tons of fossil fuel equivalent ( approx. 11.2%), FOi

stands for effective fraction oxidized in the year of production and Ci for carbon content

in tons C per ton coal equivalent/ tons C per thousand 1012 joules. The conversion factor used for 1 ppmv of atmosphere CO2 = 2.13 Gt C.

Each of the three water related sectors is linked with both food production and population sectors through the ‗water-stress‘ variable. The link between water and social

development is reflected in the water impacts on health. Without safe drinking water, humans cannot survive. Waterborne diseases are amongst the most common causes of illness and death, and the majority of people affected by them are living in developing countries. With the steady increase in population, people must find a way to add a huge amount of water to the global water supply every year. Moreover, some areas are expected to get a lower amount of rainfall due to climate change, and therefore these areas will face an alarming level of ‗water-stress‘. Human life expectancy is therefore expressed as an inverse function of ‗water-stress‘ level.

The agricultural sectors of many regions in the world fully depend on water supply, and this supply is limited. Irrigation continues to play a crucial role in the agricultural sector, but the limitation in water availability serves as one of the constraints for increase of the agricultural land. The agricultural sector is also inversely related to water-stress.