"I do dispute that it can be said that this has anything whatsoever to do with human activity.
Alterations in the activity of the sun are more likely to "blame" for the slight increase in temperature. This is especially obvious when you consider that the temperature on Mars also seems to be rising"
Source please?
Here's one:
Sun's Output Increasing in Possible Trend Fueling Global Warming
By Robert Roy Britt
Senior Science Writer
posted: 02:30 pm ET
20 March 2003
In what could be the simplest explanation for one component of global warming, a new study shows the Sun's radiation has increased by .05 percent per decade since the late 1970s.
The increase would only be significant to Earth's climate if it has been going on for a century or more, said study leader Richard Willson, a Columbia University researcher also affiliated with NASA's Goddard Institute for Space Studies.
http://www.space.com/scienceastronomy/sun_output_030320.html
Even more convincing is this graph:
http://www.space.com/images/suncycle_temps_0108_02.gif
You notice that the graph of solar activity and temperature are almost exactly the same.
Here's a bunch more:
Are observed changes in the concentration of carbon dioxide in the atmosphere really dangerous?.
C. R. de Freitas (2002)
Bulletin of Canadian Petroleum Geology 50, 297-327
http://bcpg.geoscienceworld.org/cgi/content/abstract/50/2/297
Climate change: Conflict of observational science, theory, and politics: Reply.
L. C. Gerhard (2006)
AAPG Bulletin 90, 409-412
http://aapgbull.geoscienceworld.org/cgi/content/full/90/3/409
The Sun's Role in Climate Variations.
D. Rind (2002)
Science 296, 673-677
http://www.sciencemag.org/cgi/content/full/296/5568/673
Causes of Climate Change Over the Past 1000 Years.
T. J. Crowley (2000)
Science 289, 270-277
http://www.sciencemag.org/cgi/content/full/289/5477/270
Climatic change in Chile at around 2700 BP and global evidence for solar forcing: a hypothesis.
B. van Geel, C. J. Heusser, H. Renssen, and C. J.E. Schuurmans (2000)
The Holocene 10, 659-664
http://hol.sagepub.com/cgi/content/abstract/10/5/659
Palaeoenvironmental evidence for solar forcing of Holocene climate: linkages to solar science.
F. M. Chambers, M. I. Ogle, and J. J. Blackford (1999)
Progress in Physical Geography 23, 181-204
http://ppg.sagepub.com/cgi/content/abstract/23/2/181
Geophysical, archaeological, and historical evidence support a solar-output model for climate change.
C. A. Perry and K. J. Hsu (2000)
PNAS 97, 12433-12438
http://www.pnas.org/cgi/content/abstract/97/23/12433