For example, from the cooleffect.org FAQ: "All carbon credits on the Cool Effect platform are from carbon projects that have been certified by one of the major

For example, from the cooleffect.org FAQ: "All carbon credits on the Cool Effect platform are from carbon projects that have been certified by one of the major international carbon credit standards, such as The Gold Standard, Verra or the Climate Action Reserve." Ultimately you have to trust an external organization like that.