Aviation contrail climate effects in the North Atlantic from 2016 to 2021

Around 5 % of anthropogenic radiative forcing (RF) is attributed to aviation CO2 and non-CO2 impacts. This paper quantifies aviation emissions and contrail climate forcing in the North Atlantic, one of the world's busiest air traffic corridors, over 5 years. Between 2016 and 2019, growth in CO2 (+3.13 % yr−1) and nitrogen oxide emissions (+4.5 % yr−1) outpaced increases in flight distance (+3.05 % yr−1). Over the same period, the annual mean contrail cirrus net RF (204–280 mW m−2) showed significant inter-annual variability caused by variations in meteorology. Responses to COVID-19 caused significant reductions in flight distance travelled (−66 %), CO2 emissions (−71 %) and the contrail net RF (−66 %) compared with the prior 1-year period. Around 12 % of all flights in this region cause 80 % of the annual contrail energy forcing, and the factors associated with strongly warming/cooling contrails include seasonal changes in meteorology and radiation, time of day, background cloud fields, and engine-specific non-volatile particulate matter (nvPM) emissions. Strongly warming contrails in this region are generally formed in wintertime, close to the tropopause, between 15:00 and 04:00 UTC, and above low-level clouds. The most strongly cooling contrails occur in the spring, in the upper troposphere, between 06:00 and 15:00 UTC, and without lower-level clouds. Uncertainty in the contrail cirrus net RF (216–238 mW m−2) arising from meteorology in 2019 is smaller than the inter-annual variability. The contrail RF estimates are most sensitive to the humidity fields, followed by nvPM emissions and aircraft mass assumptions. This longitudinal evaluation of aviation contrail impacts contributes a quantified understanding of inter-annual variability and informs strategies for contrail mitigation

"Looking all lost towards a Cook's guide for beauty”: the art of literature and the lessons of the guidebook in modernist writing

This article explores the impact of the guidebook, especially the Baedeker series, on modernist literary culture. It argues that the guidebook is a literary phenomenon in its own right and that, as such, it attracts special attention from those engaged in defending and/or extending the category of literature as part of a modernist agenda. In particular, modernist writers are concerned as to whether the guidebook counts as a form of literature and, if so, what this means for the more familiar forms seen in their own essays, fiction and travelogues. What might the invention of the star system to rank scenes and monuments mean for the future of art criticism? How might the guidebook help or hinder the traveller in his/her pursuit of the beautiful or the picturesque? What does recourse to the guidebook reveal about the taste and education of the traveller? And, more pointedly still, what kind and quality of writing is the guidebook itself? This article surveys the extent of modernism's interest in the guidebook, both as a noteworthy new form and as a form modernist writers adapted for use in their own books, before turning in detail to commentary on the guidebook by E.M. Forster, Ernest Hemingway, H.D. and Virginia Woolf. In conclusion, it finds that the guidebook in modernism is very rarely just that. Instead, the guidebook finds unexpected affinities with modernism in its attempt to “modernise” literature – to make it more rational, more totalising and, in the eyes of its critics, less able to discriminate.This is an Accepted Manuscript of an article published by Taylor & Francis in Studies in Travel Writing on 4th March 2015, available online: http://wwww.tandfonline.com/10.1080/13645145.2014.994924

Design principles for a contrail-minimizing trial in the North Atlantic

The aviation industry has committed to decarbonize its CO2 emissions. However, there has been much less industry focus on its non-CO2 emissions, despite recent studies showing that these account for up to two-thirds of aviation’s climate impact. Parts of the industry have begun to explore the feasibility of potential non-CO2 mitigation options, building on the scientific research undertaken in recent years, by establishing demonstrations and operational trials to test parameters of interest. This paper sets out the design principles for a large trial in the North Atlantic. Considerations include the type of stakeholders, location, when to intervene, what flights to target, validation, and other challenges. Four options for safely facilitating a trial are outlined based on existing air-traffic-management processes, with three of these readily deployable. Several issues remain to be refined and resolved as part of any future trial, including those regarding meteorological and contrail forecasting, the decision-making process for stakeholders, and safely integrating these flights into conventional airspace. While this paper is not a formal concept of operations, it provides a stepping stone for policymakers, industry leaders, and other stakeholders with an interest in reducing aviation’s total climate impact, to understand how a large-scale warming-contrail-minimizing trial could wor

Hybrid Aircraft for Improved Off-Design Performance and Reduced Emissions

The exceptionally high efficiency of electric motors makes them an enabler for flexible hybrid energy management, which can be used to optimize off-design aircraft operation, such as taxi and descent. The off-design operation contributes to a significant part of the global fuel usage of air transport vehicles as well as to the NOx emissions around airports. Thus, a hybrid chain designed for efficient idle operation could be an economical short-term solution for reduced global environmental impact. This paper focuses on providing and assessing such a design using a conventional 165-PAX-class transonic airliner with an assumed entry into service year of 2035 as a baseline