Given the number of people who would have to be "in on it" global tax conspiracies are nonsense as are the theories of the U.N. wanting to control the world. While winter and summer cycles still continue with global warming the Arctic is certainly showing a downward trend over the last couple of decades the summer size of the ice is plainly and obviously shrinking.
http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=09&fd=15&fy=1988&sm=09&sd=15&sy=2008
The Sun is the primary source of heat for the Earth and the Sun does change output but it hasn't markedly changed output since satellite records began 30 years ago but the Earth has warmed right through this period.
The power of the Sun falls with distance Mercury is closest and should be hottest, Venus is next and should be much cooler but it's atmosphere makes it hotter than Mercury. Earth is next and without GH gases would be about 30c cooler than it is, out to Pluto at -218c.
The NSIDC is just one of many groups collecting data on climate around the world from the U.K to Asia, the rest of Europe, Australia and the U.S. while there is some dispute over the scale of the change there is no dispute that it is happening.
http://www.ncdc.noaa.gov/oa/climate/research/2008/nov/global.html
http://climate.jpl.nasa.gov/
http://nsidc.org/data/seaice_index/
http://www.metoffice.gov.uk/climatechange/guide/
http://www.bom.gov.au/climate/