I don't believe this is accurate. From the wiki: > The caps at both poles consist primarily of water ice. Frozen carbon dioxide accumulates as a comparatively

I don't believe this is accurate. From the wiki: > The caps at both poles consist primarily of water ice. Frozen carbon dioxide accumulates as a comparatively thin layer about one meter thick on the north cap in the northern winter, while the south cap has a permanent dry ice cover about 8 m thick.