John Jones (Letters, Nov. 1) states that the idea of a heat-trapping blanket around the earth is a violation of thermodynamics. He is wrong. There is nothing in thermodynamics that forbids this, and, in fact, we are familiar with many examples of such a phenomenon.

Sweaters and blankets keep us warm, even though they themselves are cooler than our bodies. Insulation keeps our houses warm even though the insulation is cooler than the interior of the house.

A cloudy night is warmer than a clear night, even though the clouds are cooler than the surface of the earth. Similarly the presence of the greenhouse gases in the atmosphere hinders the loss of heat to outer space and leads to a higher temperature of the earth.

Darrah Thomas, Corvallis