China Cooled Nearly 0.2°C During Global Warming Hiatus
During the global warming hiatus between 1998 and 2014 temperatures in the whole of China declined sharply, dropping by nearly 0.2°C by the end of the hiatus period. The delayed cooling observed in the Tibetan Plateau was even steeper.
A reduction in the warming rate for the global surface temperature since the late 1990s has attracted much attention and caused a great deal of controversy. During the same time period, however, most previous studies have reported enhanced warming over the Tibetan Plateau (TP). In this study we further examined the temperature trend of the TP and surrounding areas based on the homogenized temperature records for the period 1980–2014, we found that for the TP regions lower than 4000 m the warming rate has started to slow down since the late 1990s, a similar pattern consistent with the whole China and the global temperature trend. However, for the TP regions higher than 4000 m, this reduction in warming rate did not occur until the mid-2000s. This delayed warming hiatus could be related to changes in regional radiative, energy, and land surface processes in recent years. [...]
3.1 Annual Mean Temperature Variations
For the global, whole China, the TP regions lower and higher than 4000 m, the annual mean temperature showed evident rapid warming since 1980 (Figures 1 and S2). Trend analysis showed relatively little temperature change for the TP regions lower than 4000 m since 1998 (Figures 1b and S2b), and similar pattern existed for the whole China and the global temperature at the same time (Figures 1c and 1d, and S2c andS2d). The temperature for the TP regions lower than 4000 m showed almost flat trend with a rate of 0.07°C/decade during period 1998–2014 (Table 1). However, for the TP regions higher than 4000 m, the annual mean temperature kept increasing until the mid-2000s, followed by a significant decreasing trend in recent years (Figures 1a and S2a).
3.2 Warming Rates of Annual Mean Temperature
However, the temperature trajectory for the TP regions higher than 4000 m was different. For this region, the rapid warming continued until about 2005, when the warming rate peaked and started to decline (Figure 2).