I never said the sun had nothing to do with our climate. I was pointing out that the sun's radiance hasn't increased over the past 30 years, while global temperatures have increased. The whole point of the Neptune article is that increased solar radiation must have forced Neptune's warming therefore it must also be forcing Earth's warming. The fact that radiance hasn't increased breaks that whole argument down.

Dahliatravers, apologies for the delay in replying (I have only so much time per day to spend blogging). Thanks for your great reply - I appreciate you addressing the science, providing links to source material and taking no cheap shots :-)

The Duke Uni article is an interesting one. Do you agree with the part that says "they emphasized that their findings do not argue against the basic theory that significant global warming is occurring because of carbon dioxide and other "greenhouse" gases"?

Reading through the article reminds me of the hockey stick drama. In that case, an initial study by Mann gave us the hockey stick graph, McIntyre countered Mann's statistical methods with his own methods and they've continued haggling about various methologies to this day. However, the debate is moot as since then, multiple studies using independent methods have produced the same results.

Similarly, the PMOD satellite measurements are confirmed by reconstructions by the Max Planck Institute and direct measurements of sunspot numbers, solar flare activity and radio flux. When you find scientists squabbling over statistical methods, a good referee is independent studies in the same field.

To answer your question re computer models, climate is complex and models are always being refined (as is proper). This uncertainty is reflected in the IPCC report with language like "likely" and "very likely" expressing probabilities. Climate models are certainly not suited to predicting specific weather conditions as weather is chaotic and unpredictable - climate is concerned with long term trends which filter out chaotic noise.

The pertinent point is that, while stressing that the physics of CO2 being a greenhouse gas is undisputed, climate models fail to predict recent warming without taking rising CO2 levels into account. It's also useful (as well as relevant to the discussion on solar radiation) to view a plot of temperature over the 20th century along with the various forcing that influence global temperature. The climate model (the grey shaded area), when factoring in CO2, measured radiation levels, falling sulfate levels, etc successfully predicts temperature rises in the early decades, the mid-century cooling (a trend skeptics love to bring up) and the current warming.

How do I explain medieval warming? Climate changes naturally. It was cooler in the 19th century, it was warmer in the 1100's. No climate scientist will deny that climate changes naturally and to say otherwise is a straw man argument. What we're saying now is the current climate change is both anomalous to natural changes (eg - much more dramatic than natural change) and forced by CO2 emissions. Multiple proxy studies of temperature change over the past 1000 years all come to the same conclusion: "although each of the temperature reconstructions are different (due to differing calibration methods and data used), they all show some similar patterns of temperature change over the last several centuries. Most striking is the fact that each record reveals that the 20th century is the warmest of the entire record, and that warming was most dramatic after 1920."

Lastly, re your question about China's CO2 emissions. To be honest, I'm not a greenie or a socialist - my primary interest and attention has been on the science. It concerns me that many people make decisions on whether global warming is man caused or not based on political reasons when it's a purely scientific matter. So I argue the science and consider discussions on Al Gore, socialism, carbon credits etc irrelevant to the question "is global warming caused by manmade CO2 emissions?"

Therefore I'm not as informed on the economic issues as much as the science issues (although I plan to remedy that) so I'm reluctant to get in an argument about it until I'm more informed. To take a simplistic approach, I would liken it to the water restriction levels currently in force in my neighbourhood. We're encourage to take 4 minute showers. The China argument is akin to saying "my neighbour takes long showers so I'll be damned if I'm going to use less water than him". America is responsible for 25% of the world's CO2 emissions so are in an ideal position to lead the world in this problem. But before that can happen, the first step is admitting we have a problem which many people are reluctant to do.