Climate variations on the Tibetan Plateau since the 1970s.

<p>a, Map showing the northward migration of 5-year annual average zero-temperature isolines (at 4500 m a.s.l). b, c, d, Variations in annual average temperature (b), precipitation (c), and evaporation (d) in five regions (A–E). e, Potential evapotranspiration trends before and after 1998 derived from meteorological stations within the Tibetan Plateau. The increasing or decreasing trends over time are represented by the correlation coefficient, R (R>0 indicates an increasing trend, and R<0 a decreasing trend).