Tropical-Polar Heat Transport (IMAGE) Dartmouth College Caption A strong temperature gradient (above) delivered warm air from the tropics to the poles during the last ice age. When warming in the poles created a weaker temperature gradient (below), less warm air was transported from the tropics, causing accelerated warming in the region. Credit Illustration by Margaret Jackson Usage Restrictions Must credit: Margaret Jackson. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.