Question

scientists can directly measure the amount of co₂ in the atmosphere today. researchers at the mauna loa observatory in hawaii have been doing this since the 1950s. to determine what the atmospheric concentrations of co₂ were before they could be directly measured, 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 taken from ice drilled from deep below antarctica.
carbon dioxide concentrations over the past 400,000 years
complete the sentence.
before the last century, the highest carbon dioxide concentration occurred roughly 325,000 years ago. the atmospheric concentration of carbon dioxide today is about ___ ppm higher than it was at that time.
50 100 150 200

Explanation:

Step1: Identify the value 325,000 years ago

From the graph, 325,000 years ago, the \(CO_2\) concentration was approximately \(275\) ppm.

Step2: Identify the current value

Today's \(CO_2\) concentration is approximately \(375\) ppm.

Step3: Calculate the difference

Subtract the past value from the current value: \(375 - 275=100\)

Answer:

\(100\)