8th Grade Unit 9: Climate Change

Which of the following is a primary way that volcanic eruptions can influence climate?

• By releasing large amounts of ash and gases into the atmosphere

• By increasing the Earth's orbital electricity

• By decreasing solar activity during the eruption

• By shifting tectonic plates

Answer explanation

Volcanic eruptions release large amounts of ash and gases, such as sulfur dioxide, into the atmosphere. These can reflect sunlight and lead to temporary cooling, significantly influencing climate patterns.

What is the most common effect of increased solar activity on the Earth's climate?

• Temporary cooling of global temperatures

• Long-term warming of global temperatures

• No significant impact on global temperatures

• Increased frequency of volcanic eruptions

Answer explanation

Increased solar activity leads to more energy reaching Earth, contributing to long-term warming of global temperatures. This effect is more significant than any temporary cooling or other impacts listed.

Over long periods of time, which of the following natural processes can change the atmosphere and affect the climate? Select TWO correct answers.

• deforestation

• power generation

• plate tectonics

• petroleum extraction

Answer explanation

Deforestation alters the carbon cycle, increasing greenhouse gases and affecting climate. Plate tectonics can change landforms and ocean currents over time, influencing climate patterns. Both processes significantly impact the atmosphere.

What is one of the primary ways large meteor impacts can contribute to long-term global warming?

• By blocking incoming solar radiation

• By releasing significant amounts of greenhouse gases

• By disrupting the marine carbon cycle

• By destroying ecosystems and altering food chains

Answer explanation

Large meteor impacts can release significant amounts of greenhouse gases, such as carbon dioxide and methane, into the atmosphere. This increase in greenhouse gases can trap heat and contribute to long-term global warming.

The flood of freshwater from ice melt can alter ocean circulation patterns and influence regional or global climate in two ways:

• By increasing the salinity of ocean water and enhancing ocean currents

• By decreasing the salinity of ocean water and disrupting ocean currents

• By increasing ocean temperatures and stabilizing climate patterns

• By decreasing ocean temperatures and promoting ice formation

Answer explanation

The correct choice is that ice melt decreases the salinity of ocean water, which disrupts ocean currents. This alteration can significantly impact climate patterns by affecting heat distribution in the oceans.

Which of the following greenhouse gases have increased since pre-industrial times?

Answer explanation

Since pre-industrial times, greenhouse gases like carbon dioxide, methane, and nitrous oxide have significantly increased due to human activities such as fossil fuel burning and agriculture, contributing to climate change.

Which of the following gases contribute to global warming?

• Carbon dioxide

• Nitrous Oxide

• Sulfuric acid

• Methane

• Hydrogen peroxide

Answer explanation

Carbon dioxide, nitrous oxide, and methane are greenhouse gases that trap heat in the atmosphere, contributing to global warming. Sulfuric acid and hydrogen peroxide do not have this effect.

Complete the statements about deforestation using the drop-down menus. Deforestation not only releases stored carbon but also reduces the Earth's ability to absorb ____. In tropical regions, deforestation can lead to a reduction in the amount of water and increased surface ____.

• carbon dioxide; temperatures

• oxygen; humidity

• methane; pressure

• nitrogen; wind speed

Answer explanation

Deforestation reduces the Earth's ability to absorb carbon dioxide, which is crucial for balancing greenhouse gases. Additionally, it can lead to increased surface temperatures due to loss of vegetation that regulates heat.

Urbanization influences climate change in two ways:

• Increases greenhouse gas emissions and reduces natural carbon sinks.

• Decreases greenhouse gas emissions and increases natural carbon sinks.

• Has no impact on greenhouse gas emissions or natural carbon sinks.

• Only affects local weather patterns without influencing global climate.

Answer explanation

Urbanization leads to increased greenhouse gas emissions from transportation and industry, while urban development often replaces natural areas that act as carbon sinks, thus reducing their capacity to absorb CO2.

Move the correct answer to each box to describe the processes in the carbon cycle. Each answer may be used more than once. Photosynthesis: [__________] + 6H2O + sunlight → [__________] + 6O2 Respiration: [__________] + 6O2 → [__________] + 6H2O + energy Decomposition: When organisms die, decomposers break down their remains, releasing [__________] into the soil or atmosphere. Combustion: Burning organic materials like coal, oil, and natural gas, releases stored [__________] back into the atmosphere as [__________].

• Answers: 6CO2, C6H12O6, carbon, carbon dioxide.

• Answers: 6O2, C6H12O6, carbon, carbon dioxide.

• Answers: 6CO2, C6H12O6, oxygen, carbon dioxide.

• Answers: 6CO2, C6H12O6, carbon, oxygen.

Answer explanation

The correct answers are 6CO2 for photosynthesis, C6H12O6 for respiration, carbon for decomposition, and carbon dioxide for combustion. This accurately describes the carbon cycle processes.