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Local to Regional Climatic Effects of Deforestation
Gao, J. and Liu, Y. De(re)forestation and climate warming in subarctic China. Applied Geography 32: 281-290.

The authors write that "deforestation exerts a number of regional and local climate effects," including "a decrease in water vapor mixing ratio (Sen et al., 2004), reduced precipitation (Werth and Avissar, 2005), and a change in the water cycle (Houghton, 1990)," along with "an increase in near-surface air temperature (Sampaio et al., 2007)."

What was done
Focusing on the latter of these impacts, Gao and Liu studied the effect of the deforestation of portions of Heilongjiang Province in Northeast China, which has an annual temperature ranging from -4°C to +4°C, its winters being "long and frigid" and its summers being "short and cool." This they did over the period 1958 to 1980, when forest cover was reduced from 238,335 km2 to 216,009 km2, and from 1980 to 2000, when forest cover was further reduced to 207,629 km2.

What was learned
Over the entire period that the two researchers analyzed (from 1958-2000), there was a nation-wide warming of 0.99°C, while the annual temperature of Heilongjiang Province rose by 1.68°C, which suggests a concomitant deforestation-induced warming of 0.69°C.

What it means
In response to the 13% reduction in forest cover over the 42-year interval that Gao and Liu studied, the mean annual temperature of Heilongjiang Province rose by 0.69°C, which is a most substantial amount, considering that they note that global temperature has only risen by an average of 0.6°C since the start of the industrial revolution. Perhaps it is not so farfetched, therefore, to think that a goodly portion of that global warming may have been due to a number of other factors that have not yet been incorporated into the climate models that attribute the bulk of the post-Little Ice Age temperature increase to increases in CO2 and other greenhouse gas emissions of mankind.

Houghton, R.A. 1990. Global effects of tropical deforestation. Environmental Science and Technology 24: 414-422.

Sampaio, G., Nobre, C., Costa, M.H., Satyamurty, P., Soares-Filho, B.S. and Cardoso, M. 2007. Regional climate change over eastern Amazonia caused by pasture and soybean cropland expansion. Geophysical Research Letters 34: 10.1029/2007GL030612.

Sen, O.L., Wang, Y. and Wang, B. 2004. Impact of Indochina deforestation on the east-Asian summer monsoon. Journal of Climate 17: 1366-1380.

Werth, D. and Avissar, R. 2005. The local and global effects of Southeast Asian deforestation. Geophysical Research Letters 32: 10.1029/2005GL022970.

Reviewed 23 May 2012