Scientific Fact!
That is what the Global Warming Nazi's are claiming when they try to scare the general populous into swallowing more and more government seizure of your tax dollars and control of big business in this country in the name of 'Global Warming'.
Global Warming is happening. This must be so right?  After all, everyone in the media is stating it as fact.
There are commercials warning parents of the effects of global warming for their children, then offering them the opportunity to save the polar bears (among other things) by joining defenders.org/global warming.com
Katie Couric does reports on its effects.  Algore has his movie where he preaches from the secular progressive bible condemning America and big business.
With so many pundits and celebrities on the side of mother earth, we on the Right are portrayed as evil polluters who greedily seek the destruction of the planet, for a profit.

Scientists say it is happening every day.  One key thing they forgot to mention is taught in the first science class you took in elementary school or at least it used to be taught.  It is called The Scientific Method.  Let me give you a definition for the scientific method, according to dictionary.com;

a method of research in which a problem is identified, relevant data are gathered, a hypothesis is formulated from these data, and the hypothesis is empirically tested.

For those of you educated in public school post 1980 empirically means it is provable by experience or experiment. 

There are three steps in the scientific method. 1. Identify the problem.  2.Write a hypothesis.  3. Prove it true or false with attempts at duplication of your results.  We only use the first two in our rush to crown global warming as one of the big issues of the day.  Where is the test, and hence the duplication of results?  It is not evident and not duplicated so the scientists just skip it and claim what is not fact. 
Here is a fact for you.
We cannot predict accurately what the weather will be like in a week.  What makes us so vain as to assume the earth will be warmer in one hundred years?

If human activity is the cause of such warming, why cant we make it warmer in areas of the earth such as Scotland, where plants don't grow due to the cool weather?  Scotland imports almost all their veggies and the cost for this is a burden to these people of planet earth and unfair right?
The fact is, we don't know why the earth has warmed up or whether it actually has.
20 years ago, the next ice age was purported to be inevitable and we were doomed. 
The fact is we don't know, period.  That is where research, and use of the scientific method in particular, is needed.  The funding of scientists who do not subscribe to the THEORY of Global Warming as fact is needed.  Much like adult stem cell research, it is where the real scientific advance of humankind will occur and not in politically driven pseudo science.