Why is there so much concern over small rises in carbon dioxide (CO2) concentrations in the atmosphere?
Return to Climate Questions and Answers In Brief: Small is a relative term. In other complex systems, like the human body, changes in chemical concentrations that make the recent rise in atmospheric carbon levels look enormous can mean the difference between life and death. The pre-industrial to industrial age difference in CO2 concentrations (280 to 390 ppm) is about the same as the difference in CO2 concentrations between the height of the last ice age (180 ppm), when a massive ice sheet extended from the Arctic to the Ohio River, and the current interglacial period (280 ppm) when human civilizations have existed. “Great changes can be brought about by very slight forces.” — Julius Caesar In science, whenever you hear the terms big or small, fast or slow, light or dark, it’s important to ask relative to what? Are the current changes in carbon dioxide (CO2) levels today really that small? In absolute terms, CO2 takes up 0.04 percent of the atmosphere. So what if the levels double to 0