A town expanded its use of natural gas for home heating.
Evidence (annual totals):
- Natural gas used: 1.2 million m (2012) → 2.0 million m (2022)
- CO measured at a local air station (average): 395 ppm (2012) → 418 ppm (2022)
- Notes: The town population grew slowly, but gas use per home also increased.
Which explanation best links the consumption change to an Earth system impact, based on the evidence? (Impacts depend on the amount and rate of use.)
- Because CO is a gas, it quickly disappears, so increased natural gas use cannot change air composition over years.
- Increased natural gas use can increase CO released to the air, changing atmospheric composition over time. (correct answer)
- The CO increase proves the town drilled more wells, so consumption is not relevant to the air.
- The CO change is caused by human decisions, not by the amount of fuel used, so the consumption data are not needed.
Explanation: Examining consumption impacts on Earth systems means connecting resource use patterns to environmental changes. Higher consumption of fossil fuels increases emissions that affect atmospheric composition. These impacts build up over time, as gases like CO₂ persist in the atmosphere for decades. To analyze consumption effects, match changes in resource use with corresponding changes in environmental measurements. A misconception is that gases disappear quickly, but many remain in the atmosphere long-term. Understanding consumption-impact relationships helps explain gradual changes in Earth's systems and supports predictions about future environmental conditions.