Facts are clearly harder to gather and vet than opinions. Look at the comments above: one beautiful set of facts ("I fail to see the link"), and a couple dozen fact-free comments about method and bias.

People who deny climate change is occurring are just in-credible, because of many undeniable global effects which can only occur in the presence of long-term, large-scale warming:

1) Ice sheets and glaciers receding

2) Polar ice melting

3) A temperature minimum below the surface of old boreholes

4) Springtime advancing

Granted, "proving" that this warming is caused primarily by CO2 is harder, but to deny the warming itself in the face of these effects is plain silly.