The article: Has CO2 warmed the planet at all in the last 50 years? It’s harder to tell than you think explains the uncertainty regarding the Anthropogenic Global Warming proposition.
It seems clear that the perception of human caused “Global Warming” is a function of several factors:
1) Urban Heat Island Effect (UHI) – the effect of concentrated human technocratic infrastructure that raises local temperatures. The proximate causes of UHI range from placement of weather recording stations in areas of artificial heat generation (airports, near air conditioners r other industrial heat sources) to generalized heat bubbles surrounding major cities. Selection of recording sites is critical in evaluating temperature records. (See numerous articles on Watts Up With That?)
3) Political agendas – environmental groups, UN/IPCC, World Bank, International Monetary Fund – organizations such as the IPCC, the Met Office, Union of Concerned Scientists, United Nations World Meteorological Organization are not scientific organizations, they are science policy organization. Therefore, the conclusions they reach and communicate are not scientific conclusions, they are policy recommendations based on interpreted results of scientific investigation. The United Nations focus is on “sustainable development,” and most, if not all of their policy documents are couched in terms of making the developed nations pay for continuing development in the “global South.” Environmental organizations such as Greenpeace, The Sierra Club, and World Wildlife Fund have changed from grassroots advocacy and action to political lobbying organizations, requiring multi-million dollar budgets and a compromising presence in world seats of power and influence.