NASA Flip Flops on Jet Contrails; Now Suggest ‘Global Cooling’

Posted on January 8, 2011 by


Jet Contrails Likely to Add to Earth’s Warming
June 23, 1999

Surface based contrails viewed from NASA Langl...
Image via Wikipedia

Those jet contrails that streak across the sky will contribute significantly to global warming within the next 50 years, say researchers. Researchers at NASA?s Langley Research Center concluded the contrails have a very small impact now, but as more jets fly, the contrails will affect the climate. (Reuters) Source :

Then three years later….

Contrail Web over the Central Rhône Valley, Eastern France

Posted August 18, 2002

The climatic impact of such clouds is poorly understood. In an unprecedented experiment following the September 11 grounding of all aircraft in the United States, researchers reported in the August 8 issue of Nature that temperatures in areas usually affected by contrail blankets fluctuated higher and lower during the contrail-free period. Despite this dramatic conclusion, it is nevertheless too early to know whether contrails produce a net warming or cooling of the atmosphere. Whereas cirrus clouds seem to have a net warming effect, contrails are denser and thus may produce the opposite effect. Source :