Abstract: Evaluation of the levels of low carbon economic development and the investigation of their spatial differences are an important step from basic (theoretical) to applied (practical) research on low carbon economy. The essence of establishing an evaluation index system is to specify the content of low carbon development in details and a criterion system for assessment in order to provide necessary theoretical support for low carbon economic development and its regulation. With reference to DPSIR (driving forces-pressure-state-impact-response) model, using carbon emission intensity, per capita carbon emission, etc. among 25 indices, an evaluation index system based on PSIR model was established to study the levels of low carbon development and their temporal and spatial differences for the major provinces in the middle and lower reaches of the Yellow River Basin from 1991 to 2010. The results indicate that, in the region under study, temporally all provinces are progressing toward low carbon economy with fluctuations; spatially the levels of the development in different provinces vary, with the highest level in Shandong and relatively lower levels in Shanxi and Henan. But the progress is faster in the provinces with lower levels of low carbon economy. With regard to the impacting factors, with the exception of pressure sub-system, all other sub-systems show highly positive correlation with low carbon economic development, with variations in the different areas of the region. In general, changes of the pressure sub-system have greatest impact on low carbon economic development, suggesting that carbon emission intensity is being continuously lowered, industrial structure continuously optimized, and the pressure on resources and the environment reduced. However, the contribution of technological progress to low carbon economic development is relatively small.

Key words: evaluation of low carbon economy, PSIR model, temporal and spatial changes, the middle and lower reaches of the Yellow River Basin