Contrails Cause More Warming Than Aircraft CO2 Emissions

Not exactly news to some of us who have been arguing the issue for quite some years, but interesting to see new research supporting concerns about aircraft contrails and their effect on climate:

The innocuous white vapour trails that criss-cross the sky may not be as harmless as they look. In fact, they might have contributed to more global warming so far than all aircraft greenhouse gas emissions put together.

High-altitude clouds like cirrus warm the planet by trapping heat. Contrail "cirrus" does the same thing, but the question is: how much? We know that contrails trap some extra energy in the atmosphere: their radiative forcing trapped 10 milliwatts per square metre (mW/m2) in 2005, according to an estimate by the Intergovernmental Panel on Climate Change. That compares with 28 mW/m2 trapped by all of the CO2 released by aircraft engines since the start of aviation.

~ ~ ~

Using satellite observations of spreading contrails as a guide, Burkhardt built a model that simulated how they form, spread out and dissipate. Then she embedded it in a global climate model and watched what happened. She found that contrail cirrus ended up covering 0.6 per cent of Earth's surface – an area nine times as great as that covered by line contrails.

Burkhardt then used this figure to produce a more accurate estimate of the total energy trapped by contrails. Her calculations suggest a global figure of 31 mW/m2 – higher than that attributable to aviation CO2.

Contrails warm the world more than aviation emissions

See:

Global radiative forcing from contrail cirrus

Also, previous items on this subject:

Longer Airline Flights Proposed to Combat Global Warming

Airplane Contrails Boost Global Warming, Study Suggests

www.abovetopsecret.com...