تجزیه و تحلیل تحول اخیر ترافیک هوایی تجاری CO 2 و استفاده از ناوگان در شش بازار بزرگ ملی در اتحادیه اروپا  Analysis of the recent evolution of commercial air traffic CO2 emissions and fleet utilization in the six largest  national markets of the European Union

1. Introduction The high growth of air transport has been accompanied by an increase in the fuel consumption and therefore CO2 emissions growth in the last decade, despite of the improvements in the industry efficiency (Lee, 2010). Although the contribution of aviation to climate change is small in relative terms, about 3% of global fossil fuel consumption and 12% of transport-related CO2 emissions, it is growing faster than other sources of emissions (Simone et al., 2013; Anger, 2010; Mayora, 2010; Macintosh and Wallace, 2009). The vast majority of these emissions come from international flights. By 2020, global international aviation emissions are projected to be around 70% higher than in 2005, which is the reference year for the baseline of the European Union (EU) Emissions Trading System (actual figure was the average of the yearly emissions during the 2004e2006, (Benito et al., 2010)), even if total system fuel effi- ciency improves by 2% per year. ICAO (2013a) forecasts that by 2050 emissions could grow up by a further 300e700%. The rapid growth in aviation emissions contrasts with the success of many other sectors of the economy in reducing emissions and it is unlikely that the ICAO goal of reaching a Carbon Neutral Growth (no CO2 emissions increase from the sector) by 2020 could be achieved using exclusively technological measures (Cheze et al., 2013
). These concerns about the future growth of CO2 emissions by air transport industry led to calls for additional market measures to restrict demand and encourage innovation in international aviation. A discussion of the pros and cons of the different measures can be found in Benito (2007). In this sense, the European Commission (2008) adopted Directive 2008/101/EC, to include aviation in the EU-ETS from the beginning of 2012 and have in study additional actions for the future (European Commission, 2011). The first international action to put limits to greenhouse gas emissions was adopted in December 1997 when the Conference of the Parties (COP) approved the Kyoto Protocol, imposingmandatory target reduction to the emissions from developed countries. There was no agreement on the allocation of international civil flights emissions and ICAO received the responsibility of controlling them at world level. The analysis carried out by ICAO showed that technical measures were insufficient for the task, without a drastic cutting of air transport growth, and Market Based Measures (MBM) were needed. After a failed intent of launching a worldwide ETS in 2007, ICAO has initiated a dual process: on one side, a new requirement for certifying CO2 emissions from new civil aircraft type should be approved in the 2016 General Assembly together with an additional requirement for models already in production. In the same meeting, Resolution A38-18 contains the approval of a Market based Measure (MBM) system, designed to offset emissions exceeding the 2020 level, is expected, starting by 2021 (ICAO, 2013b). At the same time States carrying at least 1% of international air transport RTKs are required to present to ICAO Action Plans for reducing civil aviation CO2 not later than June 2015 (ICAO, 2011).