How great is aviation's share of the world's emission of carbon dioxide?

The UN's international climate panel (IPCC) indicates that air traffic currently accounts for about 2% of the global emissions of carbon dioxide. Along with the emission of nitric oxides, steam and effects from condensation trails, aviation is estimated to account for 3.5% of the total human impact on climate. Aviation accounts for 4-5% of Sweden's total emissions of carbon dioxide. The transportation sector in turn accounts for over a third of Sweden's total emissions of carbon dioxide.