In January 1998, a collaborative ice-drilling project between Russia, the United States, and France at the Russian Vostok revealed that over the past four cycles atmospheric concentration of carbon dioxide correlates closely with Antarctic air-temperature. The analysis also suggests a sequence of events that is characteristic of every termination; warming by orbital forcing, then increasing greenhouse gases, and followed by ice sheet melting and reduced albedo.
This seminal 1976 paper tested the Milnkovitch orbital forcing hypothesis by comparing the 450,000 year geological record of the climate as recorded in marine sediments with the cycle of variations in Earth’s tilt and orbit. The analysis finds clear evidence for orbital forcing in the marine sediment record, but the authors conclude that orbital forcing by itself is not able to explain the dominant 100,000 year glacial/deglacial cycle.
Evidence from Antarctic ice cores have revealed a close correlation between surface temperature and atmospheric carbon dioxide concentration for the past 800,000 years (excluding the immediate present.) A recent analysis of Antarctic blue ice has found that the close correlation between temperature CO2 extends to 1.5 million years ago during the time when the glacial/interglacial period was 40,000 years.
Between 2005 and 2017 the U.S. economy as measured by real GDP expanded by about 20 %. Over this same period, emissions from power generation dropped which is evidence of a decoupling between economic growth and power generation.