While it is meritorious that you struggle with issues of this type, I suspect that both Adams' editorialized abduction --in the Prior Analytics sense-- and its reduction to your travel approach the 'yuk response' reaction, described by the bioethicist Arthur Kaplan to explain positions based on moral heuristics instead of dispassionate scrutiny of the information. Now, putting aside conceptual differences between morality and ethics, consider the following (which is based mostly on data published on 2005 by the World Resources Institute): First, 14% of greenhouse gas (GHG) emissions are produced by land, air, and maritime transport -- this is equivalent to 18% of the global CO² emissions. Although aviation is indeed the fastest growing GHG source in the transport sector, it is associated with just ca. 12% of the GHGs for this sector and 1.6% of the global ones. (The atmospheric impact of aviation may be boosted by non-GHG high altitude effects, but these are uncertain and hard to quantify.) To put this in context, the global GHGs associated with cement manufacturing are nearly 2.5 times those of air transport, and those of maritime transport are twice as high. Second, international air transport itself is associated with only a little more than half the overall aviation GHGs. Third, unlike cars, airplanes have a long design life, and an ecologically friendly alternative to kerosene for jet air transport is not even in the cards; the more recent Boeing and Airbus jet plane models and near future models will remain in continuous use for many years to come. Even pressure on the aviation industry for cleaner travel would not modify the status quo -- air transport, especially for international passenger travel, is likely to remain unchanged at least during much of the current century. Fourth, under current conditions, unless you own a jet or it is otherwise at your service, deciding whether to take or not an international flight has no impact at all --except for the rare case when otherwise there would be not enough passengers to justify flying-- on the GHG total that particular plane will generate over its long design life. Applying moral heuristics to complex situations like this, especially when a full understanding of the mechanisms governing CO² concentration has not been achieved, does not work well. Personal travel choices and their atmospheric impact regarding a commercial airplane differ very much from those regarding one's car. Not taking that long-haul flight (and therefore not increasing your own per-capita GHGs) would assuage your conundrum, but this would do nothing for the planet since the jet you did not board will still produce the GHGs during the flight you decided not to take. At the same time, not taking the flight would likely not allow you to help in biodiversity preservation. I would think the choice is clear.