Global warming impacts of transport

Abstract

Global warming is expected to occur due to carbon dioxide and other gases emitted in the course of human activities. Due to uncertainties about atmospheric chemistry, few attempts have been made to quantify the impact of emissions of NOx, non-methane hydrocarbons and carbon monoxide. Atmospheric chemistry modelling at Harwell Laboratory has resulted in preliminary estimates of the impact of trace gases including NOx, many hydrocarbon species, carbon monoxide and water vapour on global warming. These estimates have been applied to emissions from transport, with particular attention to cars. It is found that the use of three-way catalysts on cars could reduce their global warming impact. IDI diesel engines have still less global warming impact. High NOx, CO and hydrocarbon emissions from DI diesels could result in a higher impact from these engines than from IDI diesels. Emissions from aircraft are injected into the troposphere at the height where they have a maximal effect on global warming. Although modelling of aircraft impact is at a very early stage, the first results indicate that air travel could become an important cause of global warming.