The impacts of climate change on regional temperature characteristics and climate zones

Global warming can lead to a more frequent occurrence of hot days and heat waves and fewer cold days and cold waves. In this paper, the daily mean temperature (TM) was divided into 7 range categories (TM <  − 15 °C, − 15 °C ≤ TM <  − 5 °C, … TM ≥ 35 °C). Then, the temperature days (TDs) were obtained and expressed as TD1, TD2, …, TD6, and TD7, which correspond well to climate zones. The changes in future TDs are obvious, especially for TD1 and TD6. Under the Representative Concentration Pathway (RCP) 8.5 scenario, TD1 will decrease the most in the polar climate zone, from 162 to 102, while TD6 in warm tropical countries and regions, such as Brazil, Nigeria, and Congo, will increase by more than 70 days, reaching at least 300 days per year after 2066. By summarizing the anomalies of TD1, TD2, TD6, and TD7 in combination into 12 templates, the changes in TD1 and TD2 were determined to be more pronounced than those in TD6 and TD7. Although carbon dioxide emissions will remain basically stable from 2066 to 2095 under the RCP4.5 scenario, both TD1 and TD2 will decrease in central Antarctica, Eastern Europe, and northern Russia, and the melting of ice and snow will be irreversible. Countries such as Saudi Arabia and Australia will still face a continuous increase in both TD6 and TD7. Temperature range changes also affect the humidity of the climate: in the projected future, humid climate areas will decrease, while arid climate areas will increase. The boreal drylands in the middle and high latitudes will be replaced by temperate drylands.