Arctic climate empirical diagnostics : a contribution to the climate change debate

A hypothesis that global climate warming observed during the last century has been due to anthropogenically induced carbon dioxide concentration growth provoked controversial response. In this context, general considerations have been discussed supporting the viewpoint that the greenhouse global warming hypothesis is doubtful, although, of course, the greenhouse effect contribution should be taken into account. One of the strongest arguments in favor of the above hypothesis is a conclusion drawn from numerical climate modeling data that there must be an enhancement of the greenhouse signal with latitude. In this paper some results of surface air temperature (SAT) observations in the Arctic during the last 20-30 years have been discussed which demonstrate a reduction in SAT in a number of Arctic regions. Some dendroclimatic data relevant to tree growth near the northern forest boundary have also been considered. Analysis of these data (covering larger time periods) reveals that not only the conclusion about polar enhancement of climate warming is wrong but the warming itself could hardly be realistic. So it may be concluded that no noncontroversial information exists that can support the hypothesis of global greenhouse warming.