Show changes of climate A scientist who recently dinv inv estimated esti gated the causes ot secular variations in tern pera ture at the earths surface thinka that they are more probably due to changes in the amount of carbonic acid in the atmosphere than to varia ions in the heat ot the sun if the amount of carbonic acid that the air now contains was diminished a little more than halt the mean temperature all over the earth would it Is stated drop about eight degrees which would be sufficient to bring on another gla caal period on the other band an in crease of carbonic acid to between two and three limes present amount would raise the mean temperature 15 degrees and renew the hot times of the eocene epoch |