Relationship between the Standardized Precipitation Index and Global Temperature on the North American Continent

Dryness and droughts may be related to changes in precipitation due to climate change. If climate change continues, wildfires may worsen due to increased dryness. In this work, we investigated the relationship between the standardized precipitation index (SPI) and global temperature in North America. The following results were obtained: 1) The global temperature is closely related to the global ocean temperature; 2) When the global temperature increases, the SPI becomes slightly larger inland; and 3) there is no correlation between the global temperature and the SPI in coastal and highland areas. In conclusion, on the basis of this study and recent studies, we propose a climate process between the global temperature and the standardized index. The temperature changes approximately one year after the change in the ENSO index, and the CO₂ change rate follows the temperature change with a lag of several months. The emission and absorption of CO₂ at the Earth’s surface respond to temperature changes. It is like the Earth’s breathing. CO₂ emissions due to temperature increases are related to plant respiration and decomposition processes. During El Ni？o events, as indicated by changes in the ENSO index, temperatures increase, but the SPI is only slightly greater inland and is not related to changes in CO₂. Caution should be taken when interpreting the relationship between wildfires and climate change.