Increases in the concentration of greenhouse gases in Earth's atmosphere lead to warming of the Earth's global climate. This is because greenhouse gases, such as CO2 (carbon dioxide), limit the passage of ultraviolet radiation through the Earth's atmosphere.

Question

Figure 1 shows levels of atmospheric CO2 over the past 400,000 years. As Figure 1 shows, the concentration of atmospheric CO2 has risen to a higher level than at any other time in the last 400,000 years. Figure 2 shows levels of atmospheric CO2 concentration since 1750. Both figures support the hypothesis that the rate of increase of CO2 concentration in the atmosphere has been rising dramatically.

Many scientists have connected this dramatic increase in atmospheric CO2 to human activities—mainly the burning of fossil fuels and mass deforestation—that transfer stored carbon from the Earth's surface to the atmosphere. Although CO2 levels have been higher at other points in Earth's history, the high rate of increase demonstrated over the past two centuries has raised questions about how the global climate will respond to an increased greenhouse effect.

Figure 1

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Figure 2

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Answer 1

Based on the information provided, it's clear that the increase in atmospheric CO2 levels over the past 400,000 years, especially in the last two centuries, is closely linked to human activities, such as burning fossil fuels and deforestation. This rise in CO2 is significant not only in comparison to historical data but also in its rapid pace, which raises concerns about potential climate impacts.

Key Points:

1. Historical Context:

   • CO2 levels have fluctuated over millennia, but current concentrations are unprecedented compared to the last 400,000 years, according to the data in Figure 1.
   • This historical trend sets a baseline for understanding human-induced changes in atmospheric CO2.

2. Recent Changes:

   • Figure 2 illustrates the steep increase in CO2 levels since 1750, coinciding with the onset of the Industrial Revolution. This period marks significant changes in energy consumption patterns, mainly powered by fossil fuels.

3. Human Contribution:

   • The link between human activities and rising CO2 levels is well-documented. Fossil fuel combustion releases carbon that has been stored underground for millions of years, while deforestation reduces the number of trees available to absorb CO2 from the atmosphere.

4. Implications for Climate:

   • The increase in greenhouse gases, particularly CO2, is expected to enhance the greenhouse effect, leading to global warming and associated climate changes. This could result in more extreme weather patterns, rising sea levels, and disruptions to ecosystems and agricultural systems.

5. Scientific Consensus:

   • Many scientists agree that understanding the trends shown in Figures 1 and 2 is crucial for predicting future climate scenarios and developing strategies to mitigate climate change.

Conclusion:

The evidence supports the hypothesis that human activities are a significant driver of the current rise in atmospheric CO2 levels, and as a result, this is likely to have far-reaching consequences for the global climate system. Monitoring and addressing CO2 emissions is essential for managing climate change and understanding its potential impacts on natural and human systems.