Much confusion over the scientific finding, partly because of simplistic language directed at a public whom is considered incapable of understanding anything more complicated than 2 + 2 = 4.
There are two aspects to the argument; climatic change as a result of natural earth processes, and change brought about by human activities.

Climatic change has occurred throughout geologic history, as the earth's axis changes in inclination and (possibly) solar intensity variance. These changes are often referred to as cyclical, although there is more irregularity than regularity to the intervals.
In part of Tertiary time, the inclination was such that the Canadian Arctic Islands had a temperature approximating that of the Carolinas, with plant and animal life (including alligators) that offer evidence of of the strong effect. Large peat and soft coal deposits are widespread in the Arctic.
Much closer to our times, a cooler shift brought the ice ages, with warmer interglacial intervals. The last ice to affect North America impinged on northern Minnesota, some 11,000 years ago.
Many lesser shifts since then have affected man and his agriculture.

That we have shifted into a warming period is evident from the melting of the icecaps and the glaciers, the first ship to to navigate the Northwest Passage unaided (this year), partial destruction of coral beds and the shifts in marine faunas, variance in plant distribution, and other changes.

The effects of human activity are the points being argued today.

The Industrial Revolution marks the beginning of industries that burn much fuel, wood from forests or fossil fuels such as coal and, later, petroleum.
That such activities are affecting the environment is evident from analyses of ice cores taken in the Arctic and Antarctic. From the time of the Industrial Revolution, carbon dioxide and other 'greenhouses' increase in amount, becoming exponential over the last 100 years or so as more and more fossil fuels are burned and forests are stripped.
Alarmingly, toxic chemical residues made their appearance in the analyses.

How large are these man-made effects on climate? Regardless of the temperature effect, our atmosphere is being polluted, this alone should call for action.

Moreover, if (doubtfully) man's activities are not contributing to temperature increase, the 'natural' changes are enough to cause concern. Low-lying population and agricultural centers such as the Bangladesh and other deltas could be inundated, some island populations could be looking for a new home (Maldives), loss of mountain glaciers (Himalayas, etc.) impinges agriculture and human activity that needs the meltwater, decreases in rainfall cause drought, etc.
Should not these natural shifts also be planned for and contingencies formed?