The Earth's atmosphere has some capacity to hold in heat but not much of one. The current mean temperature of the Earth's surface is about 27° C. And as per scientists calculation in two months the temperature would drop to - 123° C, and - 198° C in four months. To compare, the freezing point of water is 0° C. So basically it'd get too cold for us humans within just a few weeks.

We could probably survive if we went deep underground where the Earth's internal heat is higher or if we built totally isolated habitation domes, but at the moment we are not capable of.