| Like other high, thin clouds, contrails reflect sunlight back into space and cool the planet. |
| However, the fact that the volume of air traffic is set to rapidly grow in coming years makes it important to investigate the effects of contrails on our climate. |
| Although this complicates global warming arguments, it offers further evidence that contrails do affect climate in some way. |
| The jet engine contrails have have caused most or all the warming observed in the United States for nearly 20 years. |
| The thick, twisting contrails still prevented any visual sightings. |
| In another study, a scientists observed single contrails produced by military jets that were allowed to fly during those days. |
