Question

the graph shows data from ice cores. what has happened to carbon dioxide levels over time?
atmospheric carbon dioxide
from law dome ice cores
(graph: x - axis: year (ad) 1000, 1200, 1400, 1600, 1800, 2000; y - axis: atmospheric co₂ (ppm) 280, 290, 300, 310, 320, 330, 340, 350; line is relatively flat until around 1800, then rises sharply)
options:
a. they have increased dramatically recently.
b. they have remained flat and steady.
c. they have decreased dramatically recently.
d. they have gone up and down with no general trend.

Explanation:

To determine the trend of carbon dioxide levels over time, we analyze the graph. The x - axis represents years (from 1000 AD to 2000 AD) and the y - axis represents atmospheric \(CO_2\) in ppm. From 1000 AD to around 1800 AD, the \(CO_2\) levels are relatively stable (fluctuating around 280 - 290 ppm). However, as we approach 2000 AD, the graph shows a sharp upward curve, indicating that \(CO_2\) levels have increased dramatically in recent times (near the year 2000, which is recent relative to the time span of the graph).

• Option A: Matches the observation of a dramatic recent increase.
• Option B: Is incorrect because the levels are not flat and steady; there is a sharp increase towards the end.
• Option C: Is incorrect as the levels increase, not decrease, recently.
• Option D: Is incorrect as there is a clear upward trend in recent times, not just random fluctuations.

Answer:

A. They have increased dramatically recently.