The IPCC contends the man is primarily responsible for the warming since 1975, hence the moniker anthropogenic global warming (AGW). Prior to that, the world’s climate was dictated by natural forces. It is the contention of many ‘skeptics’ that 1)the recent warm period can be explained by natural causes and 2) the recent warm period is well within historical temperature ranges. Conversely, ‘alarmists’ claim that global warming is happening, quicker than anticipated and worse than we thought.
Our first commenter, Scott, has asked me to plot the temperatures and CO2 since 1979, which I have done below. But I also plotted the sea surface temperature anomalies. I have averaged the datasets so that they are smooth in order to see any trends clearer. From this plot, it is evident that global temperature (the green line) has a lot of wiggles in it in response to the rest of the total earth-atmosphere system, e.g., sea surface temperature (the blue line). While CO2 (the red line) goes up tirelessly. This type of graph, along with global climate models, are the proof the IPCC has put forth as proof the humans are very likely (>90% chance) that humans the cause of this warming! The IPCC wants you to ignore the recent data because it does not support their agenda and does not support the notion of unequivocal warming.
However, if you DO look at the data shows that there is NO trend in the recent warming (since 1998). Run the stats – the temperature times series is flat. This contradicts the alarmists views of increasing global warming and the need for immediate action. I acknowledge that this recent data is not yet long enough to draw firm conclusions statistically. But even the most fervent alarmists requires 15 years for a statistically significant conclusion (http://tamino.wordpress.com/2009/12/15/how-long/) and we are at year 12 of 15. It seems we are on the precipice of a significant change in the recent temperature anomaly – either up, down or flat.
Any energy policy should be based on a sound and robust scientific policy. AGW does not satisfy this criteria.