Question

scientists measure the gases inside ancient air bubbles trapped in polar ice.
this graph shows data collected at the mauna loa observatory combined with data from ice drilled from deep below antarctica.
carbon dioxide concentrations over the past 400,000 years
complete the sentence.
according to the graph, carbon dioxide concentration has ______ over the past 20,000 years.
options: stayed about the same, roughly doubled, roughly tripled

Explanation:

Step1: Analyze the graph

Look at the \(CO_2\) concentration values at 20,000 BCE and today.

Step2: Estimate the change

At 20,000 BCE, the \(CO_2\) concentration was around 200 ppm. Today, it is around 400 ppm.

Answer:

roughly doubled