David S Lee

• Managing Director at Manchester Metropolitan University

The uncertainties over the effects of aviation non-CO2 emissions on climate and air quality are assessed in the context of potential mitigation measures for liquid hydrocarbon fuels. Aviation non-CO2 emissions that affect climate include nitrogen oxides (NOx), aerosol particles (soot and sulphur-based), and water vapour. Water vapour and aerosols h...

Recent studies on low aromatic fuels have shown that lower soot number emissions may reduce contrail ice particle number concentrations (Nice). Here we implemented, in a sophisticated radiative transfer model, two ice particle size distribution (PSD) schemes in order to estimate the contrail radiative forcing’s (RF) dependence on these prospective...

The effects of aviation on climate pose unique policy challenges. A large fraction of the CO2 emissions (65%) is international and not (explicitly) included in the Paris Agreement. The interpretation of Article 4.1 on achieving a “balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases” is ambiguous in the conte...

When working towards regulation of supersonic aviation, a comprehensive understanding of the global climate effect of supersonic aviation is required in order to develop future regulatory issues. Such research requires a comprehensive overview of existing scientific literature having explored the climate effect of aviation. This review article prov...

Growth in aviation contributes more to global warming than is generally appreciated because of the mix of climate pollutants it generates. Here, we model the CO 2 and non-CO 2 effects like nitrogen oxide emissions and contrail formation to analyse aviation’s total warming footprint. Aviation contributed approximately 4% to observed human-induced gl...

Aviation emissions of nitrogen oxides (NOx) alter the composition of the atmosphere, perturbing the greenhouse gases ozone and methane, resulting in positive and negative radiative forcing effects, respectively. In 1981, the International Civil Aviation Organization adopted a first certification standard for the regulation of aircraft engine NOx em...

The European Commission requested from the European Union Aviation Safety Agency (EASA) an updated analysis on the non-CO2 effects of aviation on climate change, to fulfil the requirement of the EU Emissions Trading System Directive (Art. 30.4). The study builds on the latest scientific knowledge and presents a fresh analysis of the main climate...

Aviation is one of the most important global economic activities in the modern world. Aviation emissions of CO2 and non-CO2 aviation effects result in changes to the climate system (Fig. 1). Both aviation CO2 and the sum of quantified non-CO2 contributions lead to surface warming. The largest contribution to anthropogenic climate change across all...

An off-line complex representation of the radiative forcing of linear contrails is applied for the first time to monthly mean 3D distributions. This representation assumes the same temperature-dependent, spatially and time-varying functions of ice water content and particle size for contrails as for natural cirrus. This complex representation is co...

Aviation emits pollutants that affect climate, including CO2 and NOx; NOx indirectly so, through the formation of tropospheric ozone and reduction of ambient methane. To improve the fuel performance of engines, combustor temperatures and pressures often increase, increasing NOx emissions. Conversely, combustor modifications to reduce NOx may increa...

This study evaluates the relationship between the emissions parameters of smoke number (SN) and mass concentration of non-volatile particulate matter (nvPM) in the exhaust of a gas turbine engine for a conventional Jet A-1 and a number of alternative fuel blends. The data demonstrate the significant impact of fuel composition on the emissions, and...

Trajectory optimisation is one option to reduce air traffic impact on environment. A multidimensional environmental assessment framework is needed to optimize impact on climate, local air quality and noise simultaneously. An interface between flight planning and environmental impact information can be established with environmental cost functions....

This paper describes the current status of knowledge regarding the impact of aviation on the atmosphere. The growth of the aviation industry is likely to continue in the future and at present there are significant concerns that this will adversely affect climate and local air quality in the vicinity of airports. Indeed, it is possible that air qual...

Greenhouse gas emissions associated with Representative Concentration Pathway RCP2.6 could limit global warming to around or below a 2 °C increase since pre-industrial times. However this scenario implies very large and rapid reductions in both carbon dioxide (CO2) and non-CO2 emissions, and suggests a need to understand available flexibility betwe...

The aviation community in Europe aspires to develop an economic future that is sustainable in terms of fuel supply and with regards to climate impact. Sustainable alternative fuel pathways have begun to emerge as a promising option to augment and diversify fuel supplies whilst simultaneously reducing its environmental impact and emissions. It is th...

Three global chemistry-transport models (CTM) are used to quantify the radiative forcing (RF) from aviation NOx emissions, and the resultant reductions in RF from coupling NOx to aerosols via heterogeneous chemistry. One of the models calculates the changes due to aviation black carbon (BC) and sulphate aerosols and their direct RF, as well as the...

The project 'REACT4C' explored the feasibility of operational measures such as flight altitude and route changes to reduce the climate impact from aviation. Simplified mitigation studies were conducted as part of the project to quantify the environmental benefit of simplified Air Traffic Management (ATM) measures and these results were used to form...

The atmospheric impact of aircraft NOx emissions are studied using updated aircraft inventories for the year 2006, in order to estimate the photochemistry-related mitigation potential of shifting cruise altitudes higher or lower by 2000 ft. Applying three chemistry-transport models (CTM) and two climate-chemistry models (CCM) in CTM mode, all inclu...

Foreword by the Secretary-General,Mr Koji Sekimizu In recognition of the magnitude of the climate change challenge and the importance of global action to address it, we, at IMO , for some time now, have been energetically pursuing the development and implementation of measures to address greenhouse gas (GHG) emissions from international shipping....

This study evaluates the capabilities of the carbon cycle and energy balance treatments relative to the effect of aviation CO2 emissions on climate in several existing simplified climate models (SCMs) that are either being used or could be used for evaluating the effects of aviation on climate. Since these models are used in policy-related analyses...

The Antarctic polar night jet has intensified during spring in recent decades due to stratospheric ozone depletion and rising greenhouse gas (GHG) concentrations and this has had substantial effects on the region's climate. GHG concentrations will rise over the 21st century whereas stratospheric ozone is expected to recover and there is uncertainty...

Available at http://www.easn.net/workshops/1/18/

The present study provides a detailed assessment of the net impact of global flight altitude changes on radiative forcing and temperature response. Changes in contrail coverage, chemical perturbations (H2O, O3, CH4) and associated radiative forcings were determined from simulations with a quasi CTM. Future development of global mean radiative forci...

The dependence of the radiative properties of persistent linear contrails on the variability of their ice water path is assessed in a two-stream radiative transfer model. It is assumed that the ice water content and the effective size of ice crystals in aged contrails do not differ from those observed in natural cirrus; the parameterization of thes...

We utilize a range of emission scenarios for shipping to determine the induced global-mean radiative forcing and temperature change. Ship emission scenarios consistent with the new regulations on nitrogen oxides (NO(x)) and sulfur dioxide (SO(2)) from the International Maritime Organization and two of the Representative Concentration Pathways are u...

In response to limited action on an international level, in January 2012 international aviation emissions were included within the European Union’s Emissions Trading Scheme, requiring all flights departing from and arriving to EU Member State airports to participate purchasing and surrendering carbon credits within the market. As part of a project...

The Schmidt-Appleman criterion defines the critical temperature for contrail formation. Offline contrail coverage simulations, similar to those described in Sausen et al. (1998), were conducted using ERA-Interim reanalysis data from 2001 to 2011. These updated climatological data were coupled with the distance travelled calculated by the FAST emiss...

Usage of the Global Warming Potential (GWP) is the established method for compar- ing the potential impact of emissions of different greenhouse gases on climate under the Kyoto Pro- tocol. However the GWP places emissions of gases with different lifetimes and radiative properties on a common scale. This leads to weaknesses and uncertainties, which...

We report on the particulate-bound polycyclic aromatic hydrocarbons (PAH) in the exhaust of a test-bed gas turbine engine when powered by Jet A-1 aviation fuel and a number of alternative fuels: Sasol fully synthetic jet fuel (FSJF), Shell gas-to-liquid (GTL) kerosene, and Jet A-1/GTL 50:50 blended kerosene. The concentration of PAH compounds in th...

International aviation emissions of CO2 were excluded from the Kyoto Protocol. Global aviation has grown strongly, with traffic increasing at an average rate of 4.4% per year over the period 1989–2009 but there has been no regulatory action on CO2, owing to difficulties over agreeing how emissions should be allocated to Parties. Slow progress by th...

The Antarctic polar night jet (PNJ) has been observed to intensify during spring in recent decades and this has had substantial effects on the region's climate. This intensification has been linked to the dramatic decrease in spring stratospheric ozone concentrations that began in the mid-1970s and is projected to reverse during the twenty-first ce...

The dependence of the radiative properties of persistent linear contrails on the variability of their ice water path is assessed in a two-stream radiative transfer model. It is assumed that the ice water content and the effective size of ice crystals in aged contrails do not differ from those observed in natural cirrus; the parameterization of thes...

Aviation exerts effects on climate change through CO2 emissions and its non-CO2 emissions and effects. The most up to date aviation kerosene sales from International Energy Agency data were 241.3 Tg in 2007, that is, 761 Tg of CO2. The latest global CO2 emissions data from the US Carbon Dioxide Information Center for all sources (fossil fuel, cemen...

The transport sector emits a wide variety of gases and aerosols, with distinctly different characteristics which influence climate directly and indirectly via chemical and physical processes. Tools that allow these emissions to be placed on some kind of common scale in terms of their impact on climate have a number of possible uses such as: in agre...

Aviation alters the composition of the atmosphere globally and can thus drive climate change and ozone depletion. The last major international assessment of these impacts was made by the Intergovernmental Panel on Climate Change (IPCC) in 1999. Here, a comprehensive updated assessment of aviation is provided. Scientific advances since the 1999 asse...

We present and discuss a new dataset of gridded emissions covering the historical period (1850-2000) in decadal increments at a horizontal resolution of 0.5° in latitude and longitude. The primary purpose of this inventory is to provide consistent gridded emissions of reactive gases and aerosols for use in chemistry model simulations needed by clim...

This study describes the methodology and results for calculating future global aviation emissions of carbon dioxide and oxides of nitrogen from air traffic under four of the IPCC/SRES (Intergovernmental Panel on Climate Change/Special Report on Emissions Scenarios) marker scenarios: A1B, A2, B1, and B2. In addition, a mitigation scenario has been c...

We present and discuss a new dataset of gridded emissions covering the historical period (1850–2000) in decadal increments at a horizontal resolution of 0.5° in latitude and longitude. The primary purpose of this inventory is to provide consistent gridded emissions of reactive gases and aerosols for use in chemistry model simulations needed by clim...

After 5 years of operation and collaboration the ECATS Network of Excellence (NoE) will now transform itself into a registered Association of European Research Establishments and Universities leading in the field of aeronautics and the environment. The transition from NoE to the Association will take place during 2010 and 2011. This future ECATS As...

This modelling work aims at quantifying the perturbation resulting from international maritime transport emissions of nitrogen oxides on the lower atmospheric composition and radiative forcing. We use the emission dataset created for the new IMO Greenhouse gas study as input to the tropospheric GCTM MOZART-2. We further run the Edwards & Slingo Rad...

The dual approach of using 2D and 3D Chemical Transport Models (CTMs) was adopted to deal with the temporal discrepancies of aircraft O3 and CH4 responses. A series of pulse and sustained experiments over 100-year horizons of aircraft O3 and CH4 for a range of aviation NOx emission rates were carried out. Observed at a global scale, the non-linear...

International shipping has been a fast growing sector of the global economy and its share of total anthropogenic emissions is significant, having effects on climate, air quality, and human health. The nature of the contribution to climate change is complex: In addition to warming by CO2 emissions, ship emissions of sulfur dioxide (SO2) cause coolin...

Aviation emissions contribute to the radiative forcing (RF) of climate. Of importance are emissions of carbon dioxide (CO2), nitrogen oxides (NOx), aerosols and their precursors (soot and sulphate), and increased cloudiness in the form of persistent linear contrails and induced-cirrus cloudiness. The recent Fourth Assessment Report (AR4) of the Int...

Simple climate models (SCMs) are useful tools for evaluating the climate impacts of anthropogenic emissions. As with any modelling exercise, it is important to identify and quantify the uncertainties in model results. For this study, the SCM, LinClim (Lim et al., 2007), was used to explore the sensitivity and uncertainties of various parameters inv...

The climate change objectives and policies of the European Union are based upon the concept of climate stabilization, with the premise that the climate needs to be stabilized so that temperatures increase by no more than 2°C at 2100. However, the stabilization scenarios currently published do not prescribe where emissions reductions must come from...

The purpose of this article is to describe the methodology used for generating the IPCC AR5 emissions, together with information on their availability.

The purpose of the session is to inform the aviation community in compact form about the recent IPCC findings on global climate change, and the need for reducing greenhouse gas emissions in general in the coming decades, the aviation contributions to climate change, the mitigations options, the open questions and strategies to answer them, and ongo...

An offline cirrus cloud coverage calculation was conducted using a parameterisation similar to that adopted in ECHAM (Chen et al., 1997), as part of a preliminary analysis from ongoing work on estimating the uncertainties from contrail radiative forcing. The resulting cirrus cloud coverage, calculated from ECMWF ERA-40 reanalysis specific humidity...

A simplified global climate response model was used to calculate radiative forcings and temperature responses from the emissions of shipping. Radiative forcings were calculated for 2000, which were: 0.043 W m^-2 (CO2); 0.021 W m^-2 (O3); -0.011 W m^-2 (CH4). If these forcings are combined with literature values for SO4...

Simplified climate models can be used to calculate and to compare temperature response contributions from small forcings without the need for considerable computer resources. A linear climate response model using Green’s functions has been formulated to calculate radiative forcing (RF) and the global mean temperature response from aviation. The mod...

This article has been written at the initiative of UK climate scientists, from both the academic sector and the Hadley Centre for Climate Prediction and Research, in response to an article in the previous issue of World Economics by Carter et al., which was part of a ‘Dual Critique’ of the Stern Review of the Economics of Climate Change. The cr...

Transport activity, a key component of economic development and human welfare, is increasing around the world as economies grow. For most policymakers, the most pressing problems associated with this increasing transport activity are traffic fatalities and injuries, congestion, air pollution and petroleum dependence. These problems are especially a...

New emission scenarios for aviation are provided to 2050. The emission scenarios have been developed using the SRES growth assumptions and provide an update to the emission scenarios in the IPCC Special Report Aviation and the Global Atmosphere. The emission scenarios are input to a simple climate model to provide radiative forcing and temperature...

Within the EU-project TRADEOFF, the impact of NOx (=NO+NO2) emissions from subsonic aviation upon the chemical composition of the atmosphere has been calculated with focus on changes in reactive nitrogen, ozone, and the chemical lifetime of methane. We apply a 3-D chemical transport model that includes comprehensive chemistry for both the troposphe...

Within the EU-project TRADEOFF, the impact of NOx (=NO+NO2) emissions from subsonic aviation upon the chemical composition of the atmosphere has been calculated with focus on changes in reactive nitrogen, ozone, and the chemical lifetime of methane. We apply a 3-D chemical transport model that includes comprehensive chemistry for both the troposphe...

Trends in cirrus cloud cover have been estimated based on 16 years of data from ISCCP (International Satellite Cloud Climatology Project). The results have been spatially correlated with aircraft density data to determine the changes in cirrus cloud cover due to aircraft traffic. The correlations are only moderate, as many other factors have also c...

Within the framework of the European Fifth Framework Project TRADEOFF, the impact of changing cruise altitudes on contrail coverage and corresponding radiative forcing was investigated. On the basis of the reference year 1992, a series of aircraft emissions inventories with changed flight altitudes was prepared. These emission scenarios provide flo...

Full-text of this article is not available in this e-prints service. This article was originally published [following peer-review] in Meteorologische Zeitschrift, published by and copyright Gebrueder Borntraeger Verlagsbuchhandlung. New estimates of the various contributions to the radiative forcing (RF) from aviation are presented, mainly based on...

Paper presented at the Avoiding Dangerous Climate Change Symposium in Exeter, 1-3 February 2005. Climate stabilization is embedded in UK and EU policy objectives and stabilization scenarios make assumptions over short and long-term emissions reductions. Air traffic, however, is increasing at 3 – 5% per year. The technological possibilities of reduc...

There is a need for robust methods for measuring ammonia emission rates from livestock buildings and manure stores, to guide efforts to abate emissions from livestock farming.This paper reports research to develop and validate three candidate measurement techniques:(a)An external tracer ratio method, where concentrations of ammonia and sulphur hexa...

1. The foundations of our understanding of acid deposition were laid in the last century, but the scale and scope of damage to sensitive receptors has only been subject to intensive investigation over the last 30 years or so. Negotiations are now well underway to reduce emissions, and for some pollutants policy is in place, so that these receptors...

This paper describes the current status of knowledge regarding the impact of aviation on the atmosphere. The growth of the aviation industry is likely to continue in the future and at present there are significant concerns that this will adversely affect climate and local air quality in the vicinity of airports. Indeed, it is possible that air qual...

Aircraft emissions of NOx amount to a small proportion of total emissions of NOx from man-made and natural sources. However, NOx from subsonic aircraft are directly emitted in the upper troposphere and lower stratosphere and have a relatively strong effect on the production of ozone (O-3), a greenhouse gas, in that region. Furthermore air traffic i...

The AEROCHEM studies of global aviation impacts on the atmosphere utilized 3D inventories of aviation fuel and NO, for present-day conditions, 2015 and 2050. The construction of these datasets is described and the main features of the data discussed. For 1991/92 and 2015 the differences between the available datasets are small and can be used with...

Aviation has a number of effects on climate, mediated by CO2, NOx, particle and water vapour emissions -- the latter two emissions participating in the formation of contrails. In the quantification of climate effects, it is important to characterize these emissions and forcing agents. Building on earlier work (Sausen et al., 1998), we present new r...

Currently, more deposition of reduced nitrogen species to the UK is measured than can be accounted for from the calculated emissions. A newly developed long-range transport model was used to study this budget. Changes in horizontal resolution of model and an improved parameterization of dry deposition of ammonia gave an improved agreement between m...

On the UK-scale, sulphur dioxide (SO2) dry deposition has declined at a faster rate than SO2 emissions, but S wet deposition has declined at a slower rate than emissions. Three hypotheses have been put forward to explain this non-linear response to changes in emissions: changes in the effective release height of emissions; oxidation of SO2 may have...

There are inadequate measurements of surface ambient concentrations of mercury species and their deposition rates for the UK deposition budget to be characterized. In order to estimate the overall mercury flux budget for the UK, a simple long-term 1D Lagrangian trajectory model was constructed that treats emissions (1998), atmospheric transformatio...

This paper discusses the use of a long-term Lagrangian receptor-oriented trajectory model for assessing acidic deposition to the United Kingdom at high spatial resolution. Previously, a coarse resolution of 20 km was used. Impact assessments using the critical loads approach now require higher-resolutions of modelled data for future scenarios. In t...