How does aviation contribute to climate change?
The full climate impact of aviation goes beyond the effects of CO2 emissions. Apart from emitting CO2, aircraft contribute to climate change through the emissions of nitrogen oxides (NOx). This forms the greenhouse gas ozone, especially so when emitted at cruise altitudes. Aircraft also trigger the formation of condensation trails, or contrails, and are suspected of enhancing the formation of cirrus clouds, both of which add to the overall global climate change/warming effect. These extra impacts are examples of effects which are collectively known as "radiative forcing". There is still considerable scientific uncertainty about the scale of the impact of these radiative forcing effects. However, the climate impact of aviation emissions, including radiative forcing, has been estimated by the Intergovernmental Panel on Climate Change (IPCC) to be 2-4 times that of the CO2 emissions alone. Carbon Advice Group uses the DEFRA recommended factor of 1.9 when calculating your offset