Climate Change Study via the Centennial Trend of Climate Factors

Background: The purpose of this work is to discover underlying trends of climate factors, identify their peaks and inflection points between 1880 and 2017, and study their response to climate change. Five climate factors including Land Temperature, Sea Surface Temperature, Temperature Over Land Plus Ocean, Carbon Dioxide concentration, and Northern Hemisphere Sea Ice Extent are studied in this paper. Methods: First, the kernel regression is applied to smooth and recover underlying trends of the climate factors between 1880 and 2017. To characterize temporal changes in the global climate via climate factors, peaks and inflection points of each climate factor are located and identified. Results: Five climate factors are studied between 1880 and 2017. Despite locating multiple inflection points in the climate factors and indicating fluctuations in the weather patterns, it was observed that Land Temperature, Sea Surface Temperature, Temperature Over Land Plus Ocean, and Carbon Dioxide concentration have experienced consistent increasing trends since the mid 20 t h century. It was also observed that in response to climate change, the Northern Hemisphere Sea Ice Extent has experienced a consistent decreasing trend since the 1960s. Conclusion: An increasing trend was observed for four climate factors (all but Sea Ice Extent) since the early 1900s. Sea Ice Extent shows a consistent decreasing trend dropping to a new minimum, year after year. Among all factors, the Sea Surface Temperature shows a decreasing trend between the late 1800s and the early 1900s. It reaches its minimum in 1911 and has experienced an increasing trend since then. Our observations agree with the global heat content map during this time interval between 1880 and 2017. The heat content in the Americas, Europe, Africa, Asia, and Australia shows an increasing trend since the late 1800s. It agrees with what was observed in the Land Temperature anomalies. In contrast, the heat content of the Pacific, Atlantic, and Indian Oceans shows a decreasing trend from the late 1800s to the early 1900s when its trend turns the course to an increasing trend.