What share of global CO₂ emissions comes from aviation?

What share of global CO₂ emissions comes from aviation?

Subject: Environment

Section: Climate change

Context:

• Flying, despite being highly carbon-intensive, contributes only 2.5% to global carbon emissions because only about 10% of the world’s population flies regularly.

Details:

• As global incomes rise, however, this percentage and the consequent emissions are expected to increase.
• Total CO2 emissions are often explained through the Kaya identity, which considers population, income, energy efficiency, and carbon intensity. Since 1990, demand for air travel and freight has quadrupled, with passengers travelling over 8 trillion kilometres by 2019, equivalent to nearly a light-year.
• Despite this surge in demand, the carbon efficiency of flying has improved significantly due to advancements in aircraft design, technology, and higher passenger load factors, which have more than doubled the energy efficiency of flying from 2.9 megajoules per passenger-kilometre in 1990 to 1.3 megajoules in 2019.
• However, the carbon intensity of aviation fuel has remained unchanged, as jet fuel used today is the same as in 1990, with biofuels making up only a minor fraction of the fuel mix.
• As a result, while the efficiency gains have helped reduce per-kilometre emissions from 357 grams of CO2 in 1990 to 157 grams in 2019, the overall CO2 emissions from aviation have doubled from about 0.5 billion tonnes in 1990 to about 1 billion tonnes in 2019 due to the increased demand.
• Looking back further, emissions have quadrupled since the 1960s, highlighting the significant impact of rising aviation demand over time.
• Despite efficiency improvements, the increase in aviation’s share of global emissions since 2010 underscores the ongoing challenge of mitigating aviation’s environmental impact.

Source: TH