A new study published in the journal Nature confirms yet again what climate scientists have been warning us about for decades — global warming follows CO2 increases. In particular, this study found that considerable global warming followed increases in CO2 in the world’s last deglaciation.
Global warming deniers have often argued that warming has historically first led to CO2 emissions, and not the other way around. This new study pretty clearly knocks down that house of cards. Furthermore, the argument is not that notable (or wouldn’t be that uplifting if true) anyway, since it would indicate that getting the snowball effect of a CO2 emissions–global warming–CO2 emissions–global warming cycle going is not something we want to do. Nonetheless, as the new study shows, in the Earth’s most recent deglaciation, global warming followed CO2 emissions.
“Here we construct a record of global surface temperature from 80 proxy records and show that temperature is correlated with and generally lags CO2during the last (that is, the most recent) deglaciation,” the study authors write in Nature.
“Differences between the respective temperature changes of the Northern Hemisphere and Southern Hemisphere parallel variations in the strength of the Atlantic meridional overturning circulation recorded in marine sediments. These observations, together with transient global climate model simulations, support the conclusion that an antiphased hemispheric temperature response to ocean circulation changes superimposed on globally in-phase warming driven by increasing CO2 concentrations is an explanation for much of the temperature change at the end of the most recent ice age.”
Michael Lemonick of Climate Central adds: “the most comprehensive analysis ever done of carbon dioxide and temperature at the end of the last ice age, and it shows quite clearly that in most of the world, the thermometer began to shoot up only after the atmosphere was spiked with carbon dioxide.”
And Jeremy Shakun, a Harvard postdoctoral fellow and lead author of the study, notes — “I think this ends the skeptic argument.”
Read the full Nature study or the Climate Central article on it linked above for more.