Mars holds a unique record of 4.5 billion years of solar system history in its rocks, ice, and atmosphere, according to an AGU Eos opinion article. Scientists have only begun to decipher that record, and key questions remain: why Mars became cold and dry while Earth stayed temperate, and whether it ever hosted life. Recent privately backed studies suggest that releasing metallic nanoparticles into the Martian atmosphere could raise surface temperatures by at least 30°C within a century, making terraforming look technologically possible for the first time.
The most vulnerable part of that archive is ice. Martian polar layered deposits may encode up to 30 million years of climate history, and buried mid-latitude ice could extend the record by another 470 million years. That ice may also preserve evidence of past or active microbial life. The article warns that rapid planetwide warming would melt or sublimate ice, irreversibly alter surface minerals untouched by liquid water for billions of years, and trigger rapid reactions in preserved complex molecules.
The author compares losing this record to burning the Library of Alexandria after opening only a single scroll. NASA's current Mars science plan prioritizes determining whether Mars ever supported life, understanding its climate history, and studying its geological evolution. The article argues that terraforming before those questions are thoroughly investigated would erase clues forever, and that the decision should not be left to a few powerful private actors.