Institute for Advanced Study / Princeton University Joint Astrophysics Colloquium

What we cannot create, we do not understand." Can we understand enough about climate and ecosystems to build them on other planets (and exoplanets)? A necessary, but insufficient, first step for making Mars's surface suitable for life would be to warm the planet. Motivated by our collaboration's recent work on engineered-aerosol warming of Mars (e.g. Ansari et al. Science Advances 2024), which is >5,000x more mass-effective than optimized greenhouse-gas mixes, I will discuss what we know about Mars, what we think we know about Mars terraforming (including alternative approaches), and the case for more research. Before we can assess whether warming Mars is worthwhile, relative to the alternative of leaving Mars as a pristine wilderness, we must confront practical requirements, cost, and possible risks. Further research is needed on both Mars and warming options before committing to any plan for Mars' future.