In science, truth is not judged by popular vote. In fact, the prevailing "truth" in any field of science regularly gets tossed out on its ear after a few decades (sometimes more). However, at any stage, humans would be fools to not base their behavior on the state-of-the-art in science (such as it is…see above). So, it is important to be clear about what the current consensus is, and the fact that there is one. It is always possible to find a curmudgeon to debate on TV the current state of any science. But how many are there really? The following scientific organizations have all either explicitly endorsed, or signed joint statements in support of the latest IPCC report.

National Oceanic and Atmospheric Administration
Environmental Protection Agency
NASA's Goddard Institute of Space Studies
American Geophysical Union
American Institute of Physics
National Center for Atmospheric Research
American Meteorological Society
The Royal Society of the UK
Canadian Meteorological and Oceanographic Society
American Association for the Advancement of Science
Academia Brasiliera de Ciencias (Brazil)
Royal Society of Canada
Chinese Academy of Sciences
Academie des Sciences (France)
Deutsche Akademie der Naturforscher Leopoldina (Germany)
Indian National Science Academy
Accademia dei Lincei (Italy)
Science Council of Japan
Russian Academy of Sciences
Royal Society (United Kingdom)
National Academy of Sciences (USA)
Australian Academy of Sciences
Royal Flemish Academy of Belgium for Sciences and the Arts
Caribbean Academy of Sciences
Indonesian Academy of Sciences
Royal Irish Academy
Academy of Sciences Malaysia
Academy Council of the Royal Society of New Zealand
Royal Swedish Academy of Sciences

I would be curious to see a listing of the organizations that have opposed the findings…and political ThinkTanks and PACs don't count.