Aviation creates 5% of climate impacts and growing—more than most countries

“Work by the IPCC (International Panel on Climate Change) has been updated by the same authors. They estimate that aviation accounted for 4.9% of man-made climate impacts in 2005. This contrasts with the 2% figure that is constantly quoted by aviation lobbyists.”
— Aviation Environment Federation summary, based on “Aviation and Global Change in the 21st Century” by D.S. Lee et al

We need to cut emissions in every part of the economy, including aviation

“Delegates at the Summit recognised the important work that all industry sectors and governments must undertake in the lead up to the UNFCCC climate change negotiations in Copenhagen in December 2009. The aviation industry has been working at an unprecedented pace to reduce its emission. Delegates urged policy-makers to support these efforts by developing and adopting a global sectoral approach to aviation emissions at Copenhagen.”
—Aviation industry’s internal Summit Communiqué from 4th Aviation and Environment Summit

Scientists say we need to cut emissions by 80-90% by 2050

Gar Lipow blogged about some of the back and forth around the 80% and 90% figures.

Aviation industry plans to cut only 50% by 2050 (experts doubt if any cuts will occur)

In June 2009, the International Air Transport Association (IATA) announced that the global aviation industry would halt CO₂ emissions (i.e. 0% cuts) by 2020, and would hit 50% reduction by 2050. It’s nice that the industry is planning any cuts at all, but the planned cuts are tiny relative to what scientists and governments are mandating.
—“Carbon-Neutral Growth by 2020”, June 2009

Better technology probably won’t lead to enough efficiency

“Although some airlines may adopt technologies to reduce their future emissions, these efforts may not be enough to mitigate the expected growth in air traffic and related increase in overall emissions through 2050….One expert we met with did a rough estimate of future emissions from aircraft assuming the adoption of many low-carbon technologies such as blended wing-body, operational improvements, and biofuels. He used IPCC’s midrange forecast of emissions to 2050 as a baseline for future traffic and found that even assuming the introduction of these technologies, global emissions in 2050 would continue to exceed 2000 emissions levels. Had a lower baseline of emissions been used, forecasted emissions may have been lower. Another study by a German research organization modeled future emissions assuming the adoption of technological improvements, as well as biofuels, to reduce emissions. This study assumed future traffic growth averaging 4.8 percent between 2006 and 2026 and 2.6 percent between 2027 and 2050. While this study forecasted improvements in emissions relative to expected market growth, it estimated that by 2050 total emissions would still remain greater than 2000 emissions levels.”
—United States Government Accountability Office, Aviation and Climate Change report, June 2009, page 34