Recovering from Industrial Overshoot: Thermal Removal of Atmospheric CO2

Humanity will soon overshoot a safe level of atmospheric CO2, if it hasn't done so already. Countries, industries, and the global economy need to dramatically and quickly alter their behavior and technology to avoid this dangerous overshoot, yet this appears unlikely. Direct Air Capture of CO2 represents an insurance policy for society - a way of removing excess atmospheric CO2. I will present an approach to this problem based on thermal physics that cools cubic kilometers of air to extract CO2 as it sublimates. I propose a combination of an efficient heat exchanger, radiative cooling, and refrigeration, all at industrial scale and operated in environments at low ambient temperatures. The most challenging aspect of building a system that could remove 1 billion tonnes of CO2 from the atmosphere per year is a power demand on the scale of a nation.