The real questions are:

1. What are the various driving factors in climate change?

2. What are their relative importances?

3. Are human effects significant, or are they overridden by factors beyond human control?

4. What should we do?

Here are my answers:

1.1 Variations in the Sun's output (of unknown period and magnitude).
1.2 Periodic changes in the eccentricity of the Earth's orbit (period about 100,000 years).
1.3 Periodic changes in the inclination of the Earth's axis of rotation (nutation, period about 41,000 years).
1.4 Periodic changes in the angle between the major axis of the Earth's orbit and the axis of the Earth's rotation. (precession, period about 23,000 years).
1.5 Movement of the Earth's crustal tectonic plates which alters the shape of the continents and oceans.
1.6 Intensity of vulcanism and dispersal of volcanic ejecta.
1.7 Greenhouse gasses.
1.8 Surface albedo (reflectivity).
1.9 Atmospheric particulates (excluding vulcanism).

2. Approximately the order given, from more important to less important.

3. Only 1.7, 1.8 & 1.9 above are the results (at least in part) of human activity. These are the least important factors, but the only one that we have any chance to control.

4. Reduce the use of fossil fuel by promoting renewable alternatives. The most effective way to do this is to impose large taxes on the use of fossil fuels, and refrain from taxing renewable energy sources. We should also understand that whatever we might do will likely be totally insignificant because of the magnitude of the uncontrollable factors.

Also, we should realize that the Earth has been heating up for thousands of years and will likely continue to do so no matter what we do or fail to do about it.

This graph gives the false impression that the warming is of recent origin.

This graph gives a somewhat longer perspective. The "Little Ice Age" was likely caused by a reduction of the Sun's output for unknown reasons.

This graph gives a still longer perspective which shows that the Earth's temperature has been mainly rising (with periods of lowering) for the past 18,000 years.

This graph gives a still longer perspective that shows how the Earth's climate had changed over the past 160,000 years.

This graph gives the 800,000 year view.

Conclusion: Climate is largely beyond human control.

Graph sources:
http://www.physicalgeography.net/fundamentals/7x.html
and
http://www.clearlight.com/~mhieb/WVFossils/ice_ages.html