Aviation and the Global Atmosphere

Aviation and the Global Atmosphere
Aviation and the Global Atmosphere
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9.4. Long-Term Emissions Scenarios
Other reports in this collection
Long-term projections to the year 2050 producing 3-D emissions data have been made by the Forecasting and Economic Analysis Subgroup of CAEP, using the NASA
studies as a base (CAEP/4-FESG, 1998), and by DTI using the ANCAT studies as a base (Newton and Falk, 1997). Long-term projections of total demand, fuel
consumption, and emissions (but not providing 3-D data) have also been made by EDF (Vedantham and Oppenheimer, 1994, 1998), WWF (Barrett, 1994), and MIT
(Schafer and Victor, 1997).
Table 9-9: Summary of IPCC GDP scenarios used in FESG model.
Average Annual Global GDP Growth
Rate Scenario 1990-2025 1990-2100
IS92a 2.9% 2.3%
Predictions of traffic demand and resulting emissions beyond 2015 become increasingly uncertain because the probability for unforeseeable major changes in key
factors influencing the results steadily increases. The best approach for insight into the evolution of long-term futures is the application of scenarios. A scenario is
simply a set of assumptions devised to reflect the possible development of a particular situation over time. These assumptions are used as inputs to a model that
describes the manner in which an activity might develop over time. A range of possible futures can be described by a set of independent scenarios. The results of the
scenario are difficult to judge in terms of confidence level: They are simply the outcome of input assumptions. However, scenarios can be objectively judged as
implausible by showing that their assumptions or outcomes conflict with industry trends or with invariant rules and laws that might reasonably be expected to remain
unchanged during the scenario time period or by revealing internal inconsistencies or incompatibilities with other dominating external developments. Investigation of
the consequences and implications of scenarios can be used to support a subjective assessment regarding which of the remaining possible scenarios might be more
plausible than others.
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