Why can't the government prove global warming?

Comments on ABC report "'Inconvenient fact': Fielding courts climate change rebels" by Emma Rodgers, 13/07/2009, http://www.abc.net.au/news/stories/2009/07/13/2624157.htm?section=justin

What has the government done to easy or answer Senator Fielding's concerns? Why can't the government and its many scientists answer simple questions, if they have the facts and scientific evidence? It is very strange indeed.

The government must convince people. Global warming is not an issue of ideology and the government should not treat such an important issue that way. It must be open and transparent, using scientific evidence to make the case. Otherwise it will lose its credibility in the issue.

It should not be difficult for the government to prove the case. If it can’t do so, it would demonstrate how incompetent the government is.