An insight into aviation emissions and their impact on the atmosphere

The proliferation of aviation has brought about huge benefits to our society, enhancing global economic prosperity and allowing humanity to travel faster, further and more frequently than ever before. However, the relentless expansion of the industry is a major detriment to the environment on a local, regional and global level. This is due to the vast amounts of pollution produced from the jet fuel combustion process, that is required to propel aircraft through the air and to sustain steady level flight.

Aircraft impact the climate largely through the release of CO2, which results in a direct contribution to the greenhouse effect, absorbing terrestrial radiation and trapping heat within the atmosphere, leading to rising temperatures. However, it is also vital not to overlook the non-CO2 aircraft emissions such as NOx, soot and water vapour, which result in alternative climate change mechanisms – the indirect greenhouse effect, the direct aerosol effect and aviation induced cloudiness. When accounting for these non-CO2 effects, it can be assumed that the climate impact is doubled or tripled compared to that of CO2 alone.

This report provides the necessary background information to grasp the science behind aircraft emissions and delves into the impacts aviation has on the atmosphere’s ability to cleanse itself of harmful emissions, otherwise known as the oxidising capacity of the atmosphere. It does so through an analysis of three distinct and commonly flown flight routes, investigating the impact that each flight’s emissions have on the surrounding atmospheric chemistry and discusses the potential effects this has on our Earth-atmosphere system.

Read the full report by Kieran Tait

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Read our other blogs about air travel:

Watch our latest video on air travel at the Univeristy of Bristol.

Converting probabilities between time-intervals

This is the first in an irregular sequence of snippets about some of the slightly more technical aspects of uncertainty and risk assessment. If you have a slightly more technical question, then please email me and I will try to answer it with a snippet. Suppose that an event has a probability of 0.015 (or 1.5%) of happening at least once in the next five years. Then the probability of the event happening at least once in the next year is 0.015 / 5 = 0.003 (or 0.3%), and the probability of it happening at least once in the next 20 years is 0.015 * 4 = 0.06 (or 6%). Here is the rule for scaling probabilities to different time intervals: if both probabilities (the original one and the new one) are no larger than 0.1 (or 10%), then simply multiply the original probability by the ratio of the new time-interval to the original time-interval, to find the new probability. This rule is an approximation which breaks down if either of the probabilities is greater than 0.1. For example

1-in-200 year events

You often read or hear references to the ‘1-in-200 year event’, or ‘200-year event’, or ‘event with a return period of 200 years’. Other popular horizons are 1-in-30 years and 1-in-10,000 years. This term applies to hazards which can occur over a range of magnitudes, like volcanic eruptions, earthquakes, tsunamis, space weather, and various hydro-meteorological hazards like floods, storms, hot or cold spells, and droughts. ‘1-in-200 years’ refers to a particular magnitude. In floods this might be represented as a contour on a map, showing an area that is inundated. If this contour is labelled as ‘1-in-200 years’ this means that the current rate of floods at least as large as this is 1/200 /yr, or 0.005 /yr. So if your house is inside the contour, there is currently a 0.005 (0.5%) chance of being flooded in the next year, and a 0.025 (2.5%) chance of being flooded in the next five years. The general definition is this: ‘1-in-200 year magnitude is x’ = ‘the current rate for eve

Coconuts and climate change

Before pursuing an MSc in Climate Change Science and Policy at the University of Bristol, I completed my undergraduate studies in Environmental Science at the University of Colombo, Sri Lanka. During my final year I carried out a research project that explored the impact of extreme weather events on coconut productivity across the three climatic zones of Sri Lanka. A few months ago, I managed to get a paper published and I thought it would be a good idea to share my findings on this platform. Climate change and crop productivity There has been a growing concern about the impact of extreme weather events on crop production across the globe, Sri Lanka being no exception. Coconut is becoming a rare commodity in the country, due to several reasons including the changing climate. The price hike in coconuts over the last few years is a good indication of how climate change is affecting coconut productivity across the country. Most coconut trees are no longer bearing fruits and thos

Cabot Institute for the Environment blog

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