The allegations by British mathematician Douglas J Keenan concern the following 2 papers co-authored by Wei-Chyung Wang, a professor at the University at Albany, State University of New York:
Jones P.D., Groisman P.Y., Coughlan M., Plummer N., Wang W.-C., Karl T.R. (1990), “Assessment of urbanization effects in time series of surface air temperature over land”, Nature, 347: 169-172.
Wang W.-C., Zeng Z., Karl T.R. (1990), “Urban heat islands in China”, Geophysical Research Letters, 17: 2377-2380.
The report concludes:
First, there has been a marked lack of integrity in some important work on global warming that is relied upon by the IPCC. Second, the insignificance of urbanization effects on temperature measurements has not been established as reliably as the IPCC assessment report assumes.