A new study of Antarctic ice cores suggests that global warming is a self-perpetuating process that increases as greenhouse gas emissions rise.
“We discovered that not only does thickening the blanket of heat-trapping gases around our planet cause it to get warmer, but also, crucially, when it gets warmer this increase thickens the blanket of heat-trapping gases,” Tim Lenton, a co-author of the study, told ThinkProgress, “so we have a process called a ‘positive feedback’ that amplifies changes in the Earth’s temperature.”
ThinkProgress points out that, while warmer global temperatures have repeatedly occurred alongside increases in greenhouse gas emissions, direct evidence has yet to tie this correlation to causation. That lack of causation is what keeps politicians like Senators Jim Inhofe (R-OK) and Ted Cruz (R-TX) and influential organizations like the American Legislative Exchange Council peddling climate skepticism on behalf of fossil fuel companies.
This latest study, published Monday in the journal Nature Climate Change, uses ice cores taken from the end of ice age cycles 400,000 and 800,000 years ago to analyze the relationship between the planet’s prehistoric temperature and the composition of its atmosphere. Using a mathematical theory known as Takens’ theorem, scientists found a strong reciprocal causality between temperature and carbon dioxide levels and temperature and methane levels.
In other words, when it gets warmer, atmospheric greenhouse gases increase, and when those gases increase, they warm the planet. It’s a vicious, and troubling, cycle.
“It implies that we should expect the ‘Earth system’ to respond to anthropogenic global warming by amplifying it with the release of additional greenhouse gases,” Lenton told ThinkProgress.
Even more troubling, according to NASA, an analysis of the paleoclimate record reveals that “current climatic warming is occurring much more rapidly than past warming events.”
In fact, in the past century, the planet has warmed “roughly ten times faster than the average rate of ice-age-recovery warming.”