Question

Because of the connection between greenhouse gases and climate change, there seems to be a concerted effort to reduce greenhouse gas emissions. What does this second graph, published by the EPA, tell us about how the Hansen and Lacis model will change?

A) The Hansen and Lacis model will level out and flat-line as people gradually slow the emissions of greenhouse gases as illustrated by the EPA.
B) The Hansen and Lacis model will show a sharper incline over time as the human population on Earth grows along with greenhouse emissions as indicated by the EPA.
C) The Hansen and Lacis model will continue as it is now, with an increase in the Earth's average temperature because the EPA model shows no real change in gaseous emissions.
D) The Hansen and Lacis model will gradually turn down, showing a decrease in the Earth's average temperature because the EPA model illustrates how various sectors are reducing greenhouse gas emissions.

Answer 1

According to the EPA, the Hansen and Lacis climate model will likely show a decrease in Earth's average temperature over time if greenhouse gas emissions are substantially reduced, but the existing gases in the atmosphere will continue to cause warming in the short term.

Step-by-step explanation:

The graph published by the EPA suggests future changes to greenhouse gas emissions and their effects on climate models like the Hansen and Lacis model. If we assume a reduction in greenhouse gas emissions as indicated by the EPA, this would influence the Hansen and Lacis model to potentially show a downward trend, which corresponds with option D: The Hansen and Lacis model will gradually turn down, showing a decrease in the Earth's average temperature because the EPA model illustrates how various sectors are reducing greenhouse gas emissions.

However, it's important to note that even with reduced emissions, the impact of the greenhouse gases already in the atmosphere will still contribute to warming for some time due to their long atmospheric lifetimes and the slow response of the oceans to changes. Over time, if significant and sustained reductions in emissions are achieved, the model is likely to reflect a stabilization or decrease in global warming trends, but this change is not immediate and will take decades to centuries to be realized.