Carbon dioxide is passed through the plant material at a very specific temperature and pressure. Carbon dioxide, which is normally a gas at (or above) room temperature, can be pressurized until it becomes so dense that it takes on some of the properties of a liquid while still maintaining the fluid dynamics of a gas. In this state, CO2 is known as a supercritical fluid.
The mosaic of laws that govern CBD legality across the globe varies just as much as the legislation across the US. Generally, CBD extract is legal in most countries, but what makes it illegal is where and what it’s extracted from. Most Group of 20 (G20) countries allow CBD extracted from industrial hemp, but not CBD extracted from whole-plant marijuana. Note, however, the differences between the two. Legislation regarding international travel with CBD also varies among countries. For the foreseeable future, the best practice would be to search online, or contact the respective embassies or consulates, before traveling to determine whether your CBD is safe and legal.