Final answer:
End tidal CO₂ (ETCO₂) is the level of CO₂ in an exhaled breath, indicating respiratory function. Atmospheric CO₂ has increased since the Industrial Revolution largely due to fossil fuel emissions, affecting climate and health.
Step-by-step explanation:
End tidal CO₂ (ETCO₂) is the concentration of carbon dioxide (CO₂) at the end of an exhaled breath, which reflects the patient's ventilatory status. This measurement is commonly used in medicine to monitor the patient's respiratory function, particularly during anesthesia and in critically ill patients. It is considered a non-invasive way to estimate arterial CO₂ levels and therefore the effectiveness of the patient's ventilation.
Since the Industrial Revolution, atmospheric concentrations of CO₂ have been rising, as shown by data provided by LibreTexts™. This rise is related to increased burning of fossil fuels, as suggested by isotopic signatures. Energy-related CO₂ emissions contribute a large part to this increase, which impacts not only global climate but also has implications for human health and disease processes.