Emission scenarios

Indeed, the most important factor that affects the future estimates of climate is the (anthropogenic) emissions of greenhouse gases and all kind of aerosols. The amount of these products released into the atmosphere depends upon the socio-economical and technological development of humankind. Thus, different hypotheses about these evolutions are assumed, resulting in several emission scenarios. The scenarios used in the IPCC AR4 derive from a Special Report on Emission Scenarios (SRES) published earlier [2]. All these scenarios can be grouped in four families (storylines) that are named Al, A2, Bl, and B2. 

On the basis of results from GCM (Eig. 3) the AR4 summarizes the projected changes for the Mediterranean region (Table 1, regarding temperature changes Table 2 for precipitation), the moderate emission scenario AIB having been... 

Table 1 Summary of projections from the 21 models included in the MultiModd Data set, for the Mediterranean region (30°N, 10°W-48°N, 40-E) and the AIB emission scenario. Temperature differences (°C) between 2080-2099 and 1980-1999. The table shows the minimum, maximum, median (50%), and 25 and 75% quartile values. The frequency of extremely warm, averaged over the models, is also shown. From Christensen et al. [4]...

Nakicenovic N, Swart R (eds) (2000) IPCC Special report on emission scenarios. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 570 pp... 

Estimating future emissions is difficult, because it depends on demographic, economic, technological, policy, and institutional developments. Several emissions scenarios have been developed based on differing projections of these underlying factors. For example, by 2100, in the absence of emissions control policies, carbon dioxide concentrations are projected to be 30-150% higher than today s level. 

Exposure pathway describes how the substances enter into the human body. All possible pathways are not considered for all substances and emission scenarios, only the ones that are relevant for a specific substance and emission scenario are included. For example in the case of substances that are not present in the air, the inhalation route is not taken into account. 

Rapid thermal processing Special Report on Emission Scenarios Solid oxide fuel cell Shell coal gasification process Technical University... 

In the mid Atlantic ocean observed concentrations at A03 and A04 decrease gradually with depth, whereas A05 concentrations show an increase until 500 m and a decrease below. Modeled profiles show a similar pattern. Surface concentrations of model results are much lower than the observed ones. In addition to this the fact that profiles of all mid Atlantic sampling location are identical can be explained by missing discharge into the mid Atlantic ocean in the emissions scenario. Emissions from American fluoropolymer productions sites are released into the Atlantic Ocean solely at the mouth of St. Lawrence River. Discharge of PFOA into for example the Gulf of Mexico is not considered. 

Profiles in the Japanese Sea are similar for model and observational data. Concentration decreases down to 1000 m and remains constant below. Surface concentrations are lower for modeled profiles, most likely due to the emission scenario, that assumes identical temporal behaviour for all source points and does not capture all emitted mass. Due to the limited horizontal resolution of models, the topography of the ocean differs from the real one. In the Southern ocean concentrations were low throughout all depths, and for the measurements often below the detection limit of 6 pg/L. 

Model results in seawater are in good agreement with observational data of PFOA. Most differences can be attpageributed to deficiencies of the emission scenario. Despite this fact, the difference between model results and observational data are due to the limited horizontal and process resolution and the fact that the physical parameters of the model (temperature, surface pressure, vorticity or divergence of the wind velocity field) were not relaxed to observational data. Regarding these limitations, in particular individual vertical profiles compare quite well with observations. This study underlines the importance of the ocean as a transport medium of PFOA. The contribution of volatile precursor substances to long-range transport needs to be assessed. 

FIGURE 1.7.9 Level III fugacity distributions of benzene for four emission scenarios. 

B Earth s surface temperature Future projections differ depending upon emission scenarios, (adapted from IPCC Report 2001 [1])... 

Artola-Garicano et al. [27] compared their measured removals of AHTN and HHCB [24] to the predicted removal of these compounds by the wastewater treatment plant model Simple Treat 3.0. Simple Treat is a fugacity-based, nine-box model that breaks the treatment plant process into influent, primary settler, primary sludge, aeration tank, solid/liquid separator, effluent, and waste sludge and is a steady-state, nonequilibrium model [27]. The model inputs include information on the emission scenario of the FM, FM physical-chemical properties, and FM biodegradation rate in activated sludge. 

For the approximate C02-eq. concentrations corresponding to the computed radiative forcing due to various anthropogenic GHG emission scenarios refer to the SRES Report (IPCC, 2007a). SRES scenarios do not include explicit mitigation policies. 

IPCC (2000). IPCC Special Report on Emissions Scenarios. A Special Report of Working Group III of the Intergovernmental Panel on Climate Change. Cambridge Cambridge University Press. 

Hoogwijk et al. (2005) assume the biomass energy potential in Western Europe from energy crops, agricultural residues, forest residues and industrial biogenic residues to be of the order of 10000 PJ/year and 16000 PJ/year by 2050. The analysis is based on the IMAGE 2.2 model using the four scenarios from the Special Report on Emissions Scenarios (SRES), (Nakicenovic, 2000) as main assumptions for the included food demand and supply. 

Nakicenovic, N. (2000). Special Report on Emission Scenarios. Cambridge University Press. 

SCO SCPC SD SEC SMR SNG SOFC SPE SRES SULEV SUV Synthetic crude oil Super-critical pulverised coal System dynamics US Securities and Exchange Commission Steam methane reformer Synthetic natural gas Solid-oxide fuel cell Society of Petroleum Engineers IPCC Special Report on Emissions Scenarios Super-ultra-low-emission vehicle Sport utility vehicle... 

Computer models have been developed to predict the effects of the forcing fiuic-tions shown in Figure 25.22 on future climate change and sea level rise under a variety of what-iT scenarios. A recent set of projections based on several likely GHG emission scenarios is presented in Figure 25.23. In 1990, the IPCC presented a first set of projections, estimating that between 1990 and 2005, global average temperatures would... 

Time series predictions for various greenhouse gas emission scenarios (A2, A1B, B1, and 20th century stabiiization) and actuai observations (a) CO2 concentrations (b) giobaiiy averaged surface air temperatures and (c) sea ievei rise from thermai expansion oniy. A much iarger sea ievei rise wiii resuit if continentai ice sheets are iost. in the case of (b) and (c), several models were used to obtain the scenario estimates, i.e., PCM, (Parallel Climate Model) and CCSM3 (Community Climate System Model version 3). Source After Meehl, G. A., et al. (2005). Science 307, 1769-1772. 

Many other OECD activities on hazard/risk assessment are undertaken within programs such as Existing Chemicals, New Chemicals, and Pesticides and Biocides, which deal with specific types of chemicals. The work on exposure assessment methods is undertaken by the Task Force on Environmental Exposure Assessment, consisting of experts. Most of the outcome of this work is published in the Series on Testing and Assessment or in Emission Scenario Documents, which are available at the OECD Web site (OECD 2006a). 

OECD. 2000a. Guidance Document on Emission Scenario Documents. OECD Series On Emission Scenario Documents No 1. Environment Directorate, Joint Meeting of the Chemicals Committee and the Working Party on Chemicals, Pesticides and Biotechnology. ENV/JM/MONO(2000)12. Paris OECD. 

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