Is it global warming or not?

In Canada's National Post today there is an editorial titled "Global warming? Look at the numbers". The focus is on revised data on temperature history in the U.S. being revised lower. This changes the years where the hottest temperatures were recorded and the relationship between increased carbon dioxide emissions and temperature. The author, Lorne Gunter, is really making another point. That this change in data has not been promoted by the environmentalists and that by not doing so are reducing the credibility of their argument. I feel if you don't acknowledge opposite opinions to your own you are doomed to pursue a solution that is missing half the problem. I haven't been able to find the specific data set that is referred to and I'm sure as an editorial piece the facts are skewed to promote one opinion. However, I actually follow this type of news and this is the first I've heard of it. I've either got to stop taking weekends off or I'm only looking for what I want to see. Maybe we've all been blinded by our pursuit of getting the word out that we've overlooked contrary data.