Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
ICAO‐CAEP WG3 LTTG Fuel Review Mee7ng, London, 25th March, 2009
David S Lee (MMU) With contributions from:
Rick Miake‐Lye (Aerodyne) Malcolm Ko (NASA)
Overview Emissions and impacts Metrics and design goals What scientific consensus is available to policy making?
EMISSIONS CO2, CH4, N2O, HFC, PFC, SO2, NOx…
CONCENTRATIONS
RADIATIVE FORCING
CLIMATE CHANGE Temperature, precipitation, winds, soil moisture, extreme events, sea‐level
IMPACTS Agriculture and forestry, ecosystems, energy production and consumption, social effects
DAMAGES Welfare loss (e.g. monetary units)
Increasing relevance
Increasing uncertainty
See, for example, Fuglestvedt et al. (2003) Climatic Change, 58, 267 – 331
and IPCC WG1 (2001) Chapter 7
Emissionsover-me
Lee et al. 2009
CO2andlife-me CO2 does not have a single lifetime (≠150yrs) “About 50% of a CO2 increase will be removed from the atmosphere within 30 years, and a further 30% will be removed within a few centuries. The remaining 20% may stay in the atmosphere for many thousands of years.” (IPCC AR4, WGI, Chapter 7)
Temperature response occurs over longer timescales Sea‐level rise acts over even longer timescales
Illustra-veCO2pulse
Effect of pulse of 232 Tg kerosene
at 2005
Avia-onCO2emissionssta-s-cs IPCC 1999: 2% of global CO2 in early 1990s This peaked in 2000 at 2.74% (IEA, CDIAC data) In 2005, it was 2.5% IPCC 1999 projected absolute increases over 1992 fuel usage by factors ranging from ×1.7 to ×4.8 by 2050
IPCC 1999 2050 CO2 emissions represent fractions of 1.6% through to 4.4% of scenarios that assume no climate policy
Wheredowewanttogo? The range of IPCC SRES‐based overall scenarios indicate increases in global mean temperature of somewhere between 1.8 °C (B1 scenario, likely range 1.1 to 2.9 °C) and 4 °C (A1FI scenario, likely range 2.4 to 6.4 °C) in 2090 – 2099, relative to 1980 – 1999 temperatures (IPCC, AR4, 2007)
(so add on ~0.5 °C for from preindustrial period to target date)
If we stabilized CO2 concentrations at 450 ppm, there is a 50% chance of exceeding 2 °C by 2100
(we are at 385 ppm CO2 right now)
Mixinga450ppmstabiliza-onworldwithavia-onA1,B2typescenarios
Data sources: IPCC Ar4
A1 = 12.6% 2050 B2 = 8.8% 2050
Avia-on’scontribu-ontoRF
Lee et al`. 2009
Metricsformeasuringimpacts Evaluating and comparing impacts requires metric
RF is a ‘now’ metric; GWPs are for future impacts at some integrated TH
Comparison of impacts from a specific emission associated with aviation activities to the same emission associated with other activities Environmental cost of aviation
Relative impacts from different aviation emissions Trade off in engine/air frame/operation
ImpactfromCO2emissions CO2 emissions from all sources are equivalent
Can compare aviation CO2 emissions relative to other CO2 emissions directly to compare impacts.
Thus, can use CO2 emission directly as a metric to compare to other CO2 sources.
Designgoals Minimize tradeoffs (NOx, particulates) Ways to minimize carbon footprint while
accomplishing the mission Minimize fuel use through routing and using energy
efficient airplanes Use truly renewable fuel in aviation only if appropriate to
get carbon credit Avoid carbon fuel
Scien-ficconsensus CO2 a major contributor to human‐induced climate change
Use RF as a quantitative ‘where we are now’ metric Use GWP at 100 year ITH as equivalence standard future marginal impact equivalent CO2 emissions for long‐lived (lifetimes longer than 10 years) GHGs
Global Temperature change Potential (GTP) may be a useful comparative metric for the future
No consensus on short‐lived GHGs although this may emerge over the next few years
Thank you for your attention