Figure from Li and Zhao (2012) – Spatial distribution of high, mid and low energy consumption region in China. Data for Tibet and Taiwan are absent. Green spot is the provincial capital cities of China.
Jos de Laat has alerted us to a new paper. It is
Li, Y. and X. Zhao (2012), An empirical study of the impact of human activity on long-term temperature change in China: A perspective from energy consumption, J. Geophys. Res., 117, D17117, doi:10.1029/2012JD018132.
The abstract reads [highlight added]
Human activity is an important contributor to local temperature change, especially in urban areas. Energy consumption is treated here as an index of the intensity of human induced local thermal forcing. The relationship between energy consumption and temperature change is analyzed in China by Observation Minus Reanalysis (OMR) method. Temperature trends for observation, reanalysis and OMR are estimated from meteorological records and 2 m-temperature from NCEP/NCAR Reanalysis 1 for the period 1979–2007. A spatial mapping scheme based on the spatial and temporal relationship between energy consumption and Gross Domestic Production (GDP) is developed to derive the spatial distribution of energy consumption of China in 2003. A positive relationship between energy consumption and OMR trends is found in high and mid energy consumption region. OMR trends decline with the decreasing intensity of human activity from 0.20°C/decade in high energy consumption region to 0.13°C/decade in mid energy consumption region. Forty-four stations in high energy consumption region that are exposed to the largest human impact are selected to investigate the impact of energy consumption spatial pattern on temperature change. Results show human impact on temperature trends is highly dependent on spatial pattern of energy consumption. OMR trends decline from energy consumption center to surrounding areas (0.26 to 0.04°C/decade) and get strengthened as the spatial extent of high energy consumption area expands (0.14 to 0.25°C/decade).
Excerpts from this paper include
Besides the impact of land use change on climate, the thermal impact induced by human activity within city plays significant role and should not be ignored. One of them is the anthropogenic heat released from energy consumption. Several studies have shown that anthropogenic heat is important to the development of UHI. Simulation results from a case study in Philadelphia suggested that anthropogenic heat contributes about 2~3C to the nighttime heat island in winter [Fan and Sailor, 2005].
The conclusion contains the text
Our results show significant warming has occurred for most stations in China and the magnitude of warming is closely related to energy consumption, which represents the intensity of human activity. For high and mid energy consumption group, OMR trends decline with the decrease of energy consumption. OMR trends for high and mid energy consumption group is 0.20 and 0.13C/decade respectively. Stronger warming is observed for station with high energy consumption, which usually locates in or near cities. Therefore, the strong warming is more likely a consequence of the local thermal forcing induced by human activity.
It seems that stations belong to high and mid energy consumption group in this study are affected
by human impact to a discernible extent. Just as De Laat demonstrated, anthropogenic heat released from energy consumption may very well have contributed to the observed temperature change patterns.Thus, it may raise more attention to consider the influence of human activity on surface temperature records in the past and next decades.
This study provides even more motivation for Anthony Watts to expand his station siting quality project to the entire globe!