Question

what was one major consequence of high co2 levels during peak pangaea greenhouse conditions? desertification at coastlines, globally warmer conditions, even at the poles, decline in sea levels, expansion of polar ice sheets

Explanation:

During peak Pangaea greenhouse conditions with high CO₂ levels, global warming occurred. This led to melting of ice - sheets and a rise in sea - levels, not a decline. Also, polar ice sheets would not expand. Desertification at coastlines is not a typical major consequence of these ancient high - CO₂ greenhouse conditions. Globally warmer conditions, even at the poles, is a major consequence as high CO₂ acts as a greenhouse gas trapping heat.

Answer:

Globally warmer conditions, even at the poles