The pinna leads into the external auditory meatus which is a tube that directs sound waves to the tympanic membrane. The tube is lined with hairs which trap solid particles that may enter the ear. It is also lined by wax secreting cells whose function is to secrete wax that traps dust and prevents entry of solid particles. The wax also maintains the flexibility of the eardrum.
The cause of current climate change is largely human activity, like burning fossil fuels, like natural gas, oil, and coal. Burning these materials releases what are called greenhouse gases into Earth's atmosphere.
