Which climate-state term describes Earth's climate with relatively high global temperatures and abundant greenhouse gases?

• A. Greenhouse Earth
• B. Icehouse Earth
• C. Snowball Earth
• D. Moderate Earth

Answer: (A)

The main idea is distinguishing Earth's climate states by temperature and how much heat-trapping greenhouse gases are present. When greenhouse gases are abundant, the atmosphere traps more heat, warming the planet and often reducing ice cover. This scenario is described as Greenhouse Earth. It fits the description of relatively high global temperatures and a plentiful greenhouse-gas atmosphere, which also tends to lead to higher sea levels.

In contrast, Icehouse Earth refers to cooler periods with substantial ice sheets and lower greenhouse gas levels, Snowball Earth describes a state with near-global ice cover, and Moderate Earth isn’t a standard term used to describe a distinct climate state. So the term that best matches high temperatures and abundant greenhouse gases is Greenhouse Earth.