Temperature trends in some major countries from the 1980s to 2019.

The study of temperature change in major countries of the world since the 1980s is a key scientific issue given that such data give insights into the spatial differences of global temperature change and can assist in combating climate change. Based on the reanalysis of seven widely accepted datasets, which include trends in climate change and spatial interpolation of the land air temperature data, the changes in the temperature of major countries from 1981 to 2019 and the spatial-temporal characteristics of global temperature change have been assessed. The results revealed that the global land air temperature from the 1980s to 2019 varied at a rate of 0.320°C/10a, and exhibited a significantly increasing trend, with a cumulative increase of 0.835°C. The mean annual land air temperature in the northern and southern hemispheres varied at rates of 0.362°C/10a and 0.147°C/10a, respectively, displaying significantly increasing trends with cumulative increases of 0.828°C and 0.874°C, respectively. Across the globe, the rates of change of the mean annual temperature were higher at high latitudes than at middle and low latitudes, with the highest rates of change occurring in regions at latitudes of 80°–90°N, followed by regions from 70°–80°N, then from 60°–70°N. The global land surface air temperature displayed an increasing trend, with more than 80% of the land surface showing a significant increase. Greenland, Ukraine, and Russia had the highest rates of increase in the mean annual temperature; in particular, Greenland experienced a rate of 0.654°C/10a. The regions with the lowest rates of increase of mean annual temperature were mainly in New Zealand and the equatorial regions of South America, Southeast Asia, and Southern Africa, where the rates were <0.15°C/10a. Overall, 136 countries (93%), out of the 146 countries surveyed, exhibited a significant warming, while 10 countries (6.849%) exhibited no significant change in temperature, of which 3 exhibited a downward trend. Since the 1980s, there have been 4, 34 and 68 countries with levels of global warming above 2.0°C, 1.5°C and 1.0°C, respectively, accounting statistically for 2.740%, 23.288% and 46.575% of the countries examined. This paper takes the view that there was no global warming hiatus over the period 1998–2019. [ABSTRACT FROM AUTHOR]