What if Humans are not Responsible?

Proffessor William McKillop of University of South California declares that possible it is not the humans who are responsible for the global Warming. and he states:

Global Warming: It’s the Sun, Stupid
The main cause of global warming appears to be change in solar activity and change in the earth’s orbit and tilt. Recent reductions in sunspots on the solar surface suggest that we may be entering into a cooling period.
 Humans are responsible for only 2% to 5% of total carbon dioxide emissions and less than two-tenths of one percent (0.2%) of total greenhouse gases emitted into the atmosphere each year.
 Higher temperatures increase non-human emissions of carbon dioxide from plant-life and the sea.
 More than 17,000 scientists signed the Oregon Petition against the Kyoto Protocol because they saw “no compelling evidence that humans are causing discernible climate change.”
 The Kyoto Protocol would cost the U.S. economy $100 to $200 billion per year, as estimated by the Clinton Department of Energy.
 Kyoto would restrain temperature increases by less than one degree and delay global warming by only six years.
 Kyoto was rejected by the U.S. Senate 95-0.
 It is very likely that the so-called scientists on the IPCC assumed beforehand that global warming was due to CO2 and then, instead of treating it as a hypothesis, they estimated a simple, incomplete, relationship between temperature change and CO2. A bad model can always be used to provide a desired result.

Could he be right?