Man-made climate change is real, of that I have no doubt.
The biggest problem, as alluded to by shenmel, is that this is an immensely complex science, and it is therefore easy to select any single piece of data or any single graph to illustrate ones own point-of-view without having to understand it or explain it.
Single points of data shown out of context can show anything, but a graph such as the one below is more useful (it shows 11-year averages of surface temperature from three different sources, with the 11-year average being critical to ironing out the peaks and troughs, as for each year's data-point, the average temperature is calculated for that year and all the years +/-5 years)
Show me a graph of land-temperatures that appears flat, I'll show you a graph of deep-sea temperatures that shows a startling rise (such as the one below); show me a graph of ice-shelf surface area increasing, I'll show you a graph of a dramatic loss of global ice-volume (which takes into account thickness and surface area).
Two simple truths:
- the greenhouse effect is a very simple physical phenomenon, and is supported by incontrovertible science
- CO2 is a greenhouse gas, and has been increasing since the start of the industrial revolution due to human activity
It's not logical to argue that climate has always changed and so we shouldn't be worried. Of course it has always changed, but never at the rates of change we see now (man-made CC is - at most - a 150 year phenomenon, whereas previous comparable changes in climate took place over much longer timescales). And this also rather misses the point that controlling CC is not about "saving the Earth"....our planet will survive whether we are on it or not; it is about saving our current place on Earth. Of course, we can keep emitting greenhouse gases, and the planet's climate will change, and as humans, we may even be able to adapt to this change; but we can't expect our own lives to remain the same, or the ecosystems we live in to survive intact.