Sentences with phrase «ppm during colder periods»

That's true: levels have been known to jump around from about 200 to 400 ppm during colder periods (such as our present time), up to thousands of parts per million in warmer times, but this happens on a scale of millions of years.

Not exact matches

During the 800,000 years prior to 1750, atmospheric CO2 varied from 180 ppm during glacial (cold) up to 300 ppm during interglacial (warm) peDuring the 800,000 years prior to 1750, atmospheric CO2 varied from 180 ppm during glacial (cold) up to 300 ppm during interglacial (warm) peduring glacial (cold) up to 300 ppm during interglacial (warm) peduring interglacial (warm) periods.