What was done
The authors determined the air temperature history of coastal southern Greenland from 1958-2001 based on data from eight Danish Meteorological Institute stations in coastal and near-coastal southern Greenland, as well as the concomitant sea surface temperature (SST) history of the ocean off southwest Greenland centered on 62.5°N, 52.5°W, i.e., the Labrador Sea, based on three previously published and subsequently extended SST data sets (Parker et al., 1995; Rayner et al., 1996; Kalnay et al., 1996).

What was learned
The Greenland air temperature data showed a cooling of 1.29°C over the period of study, while two of the three SST databases depicted a cooling of 0.44°C and one of them a cooling of 0.80°C.  Both the land air temperature and sea surface temperature series followed similar patterns and were strongly correlated but with no obvious lead/lag either way.  Also, it was determined that the cooling was "significantly inversely correlated with an increased phase of the North Atlantic Oscillation (NAO) over the past few decades."  The authors say this "NAO-temperature link doesn't explain what caused the observed cooling in coastal southern Greenland but it does lend it credibility."

What it means
In referring to what they call "this important regional exception to recent 'global warming'," the authors note that the "recent cooling may have significantly added to the mass balance of at least the southern half of the [Greenland] Ice Sheet."  Consequently, since this part of the ice sheet is the portion that would likely be the first to experience melting in a warming world, it would appear that whatever caused the cooling has not only protected the Greenland Ice Sheet against warming-induced disintegration but actually fortified it against that possibility.

References
Kalnay, E., Kanamitsu, M., Kistler, R., Collins, W., Deaven, D., Gandin, L., Iredell, M., Saha, S., White, G., Woollen, J., Zhu, Y., Chelliah, M., Ebisuzaki, W., Higgins, W., Janowiak, J., Mo, K.C., Ropelewski, C., Wang, J., Leetmaa, A., Reynolds, R., Jenne, R. and Joseph, D.  1996.  The NCEP/NCAR 40-year reanalysis project.  Bulletin of the American Meteorological Society 77: 437-471.

Parker, D.E., Folland, C.K. and Jackson, M.  1995.  Marine surface temperature: Observed variations and data requirements.  Climatic Change 31: 559-600.

Rayner, N.A., Horton, E.B., Parker, D.E., Folland, C.K. and Hackett, R.B.  1996.  Version 2.2 of the global sea-ice and sea surface temperature data set, 1903-1994.  Climate Research Technical Note 74, Hadley Centre, U.K. Meteorological Office, Bracknell, Berkshire, UK.