Question

which of the following is not a current theory regarding global climate change?
a. global warming will stimulate crop growth.
b. even the moderate projections on global warming will cause devastation.
c. higher levels of carbon dioxide in the atmosphere will have no effect.
d. sea levels will rise as a result of global warming.

please select the best answer from the choices provided

○ a
○ b
○ c
○ d

Explanation:

To determine the answer, we analyze each option:

• Option a: Some theories suggest increased CO₂ (from global warming) might initially stimulate crop growth in some regions, so this is a current theory.
• Option b: Many scientific projections and theories warn that even moderate global warming can cause devastation (e.g., extreme weather, ecosystem collapse), so this is a current theory.
• Option c: Higher CO₂ levels in the atmosphere are known to contribute to the greenhouse effect, leading to global warming and various impacts (like ocean acidification, climate shifts). The idea that it "will have no effect" goes against scientific consensus and is not a current valid theory.
• Option d: Global warming causes ice sheets/glaciers to melt and thermal expansion of oceans, leading to sea - level rise, which is a well - established current theory.

Answer:

C. Higher levels of carbon dioxide in the atmosphere will have no effect.