Eco-geographical region which is regional scale ecosystems in geographical zonality synthetically indicates the geographical difference of natural factors, such as climate, vegetation, hydrological pattern, soil and landform. Research revealed that many potential feedback mechanisms between the impacts of climate change on the global climate system, such as greenhouse gas emissions or uptake by ecosystems, are controlled to some extent by changes in ecosystem distribution and character and particularly by large-scale movement of vegetation zones. Despite the well-documented effects of global climate change on terrestrial species’ ranges, eco-geographical regions as the regional scale of ecosystems have been poorly studied especially in China with diverse climate and ecosystems.

A research group led by Prof. WU Shaohong and Prof. ZHENG Du, from Institute of Geographic Sciences and Resources Research (IGSNRR), CAS and other institute, have engaged in the study on eco-geographical region system for many years. They recently analyzed the shift of temperature zones in eco-geographical study over China using projected future climate scenario.

Projected climate data with high resolution (50 km×50 km) during 1961–2080 were simulated using RCMs (Regional Climate Models) of PRECIS (Providing Regional Climates for Impacts Studies) system. The number of days with mean daily temperature above 10℃ and the mean temperature of January are usually regarded as the principal criteria to indicate temperature zones, which are sensitive to climate change. Specifically, temperature zone in China was classified to Cold Temperate Zone with D10<100, Temperate Zone with 100≤D10≤170, Warm Temperate Zone with 170<D10≤220, Subtropical Zone with 220<D10≤365, and Tropical Zone with T1>14℃. Since Tibetan Plateau is one special region characterized by alpine climate for its high altitude, it is divided into two sub-regions and analyzed as a special geographical unit confined within the current borderlines. Plateau Sub-cold Zone is the area with D10<50, Plateau Temperate Zone D10>50. Shifts due to future climate change were calculated by comparing the latitude of grid cells for the future borderline of one temperature zone with that for baseline period (1961–1990).

Figure Change of temperature zones over China in future (a) baseline period; (b) near term; (c) mid-term; (d) long term

Results indicated that the ranges of Tropical, Subtropical, Warm Temperate and Plateau Temperate Zones would be enlarged and the ranges of Cold Temperate, Temperate and Plateau Sub-cold Zones would be reduced. Cold Temperate Zone would probably disappear at late this century. North borderlines of temperature zones would shift northward under projected future climate change, especially in East China. Farthest shifts of the north boundaries of Plateau Temperate, Subtropical and Warm Temperate Zones would be 3.1°, 5.3° and 6.6° latitude respectively. Moreover, northward shift would be more notably in northern China as future temperature increased.

The research has focused on the climatic factors determined the spatial pattern of regional scale ecosystems. The ranges of individual temperature zones are likely to shift as a result of climate change. Such simple relationship provides an exact glimpse into how species and vegetation zones will respond to climate change. However, there remain uncertainties about the possible magnitude changes in eco-geographical regions not only due to gaps in climate system and prediction model but also in biological factors. Moreover, the lag response of ecosystem to climate change complicates the prediction. Therefore the response and adaptation of eco-geographical regions to climate change need to be further researched despite the above uncertainties.