Question

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

co₂ concentration (ppm)
400
350
300
250
200
150
100
50
0
400,000 bce 300,000 bce 200,000 bce 100,000 bce 0
year

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 CO₂ concentration 325,000 years ago

From the graph, 325,000 years ago (around 300,000 BCE), the CO₂ concentration was approximately 250 ppm.

Step2: Determine the current CO₂ concentration

Today's CO₂ concentration (from the graph) is approximately 400 ppm.

Step3: Calculate the difference

Subtract the past concentration from the current one: \(400 - 250=150\)

Answer:

150