Ah, the global warming Denial Lobby. They are tenacious, if nothing else. Despite the fact that every single global warming scientist, every single peer reviewed article on the subject and every single respectable conference on climate pretty much agree that the evidence is rock solid that human-caused global warming is happening, is affecting us, and, at best, we have a 10 year window of opportunity to do something about it, I still get whining emails from Denial Lobby hacks that question my ability to understand science, but cite no scientific evidence of their own.

I recently highlighted the debunking of one global warming Denial Lobby effort, the British docudrama, one might call it (propaganda piece would be an accurate term) called “The Global Warming Swindle” which was soundly repudiated by the very scientist they were trying to use to support their claims that global warming is a myth.

Well, one response I got via email in regards to this was from someone who refused to even discuss the actual scientific literature, and who immediately called into question my understanding of science (then objected when I questioned the scientific basis of his statements). His fairly long series of insulting and insulted emails boiled down to two questions, poorly presented, which probably represent the latest in right wing talking points on the global warming issue. Here are his two questions (gleaned from a great deal of creationist style posturing):

" I suspect you can not even prove that the earth's temperature has ever even been measured accurately. How would you prove that? "

"Tell me how could you ever measure the level of the seas?"

So, in the aftermath of the factually incorrect and completely misleading “Global Warming Swindle” on British television, this seems to be the latest Denial Lobby attempt to deny the scientific underpinnings of global warming.

To me these questions are perfect examples of what the Denial Lobby specializes in: finding questions that SOUND relevant, but are in reality completely beside the point. However, before I wrote about it I checked with two climatologists (one of them my wife!). What follows is drawn a little from what I would have said anyway, and a lot from what my wife and her fellow climatologist told me.

The bottom line is, you do not need an accurate measure of either to demonstrate changes in temperature or sea level. Or ANYTHING, for that matter. What you need are comparable measurements that demonstrate the rate of change. Let’s say you have a yardstick that has 11 inches to the foot. It would be, in a way, inaccurate. But if you consistently used that yardstick to measure the growth of a child, you would still have a precise measure of the rate of change of that child. As long as your standard of measure remained the same, your measurement of the change would be correct. Similarly, it doesn’t matter if you use a yardstick or a meterstick if your concern is demonstrating a change. You just need to be consistent.

This is the case with the demonstrations that temperature has been increasing and sea levels have started to rise. Let me be clear. The increasing temperature is about as rock solid as you can get. There is no uncertainty that there is an unprecedented increase in atmospheric carbon dioxide that correlates with an unprecedented increase in temperature. These are not absolute numbers, they are CHANGES. And they are happening. The uncertainties are when you have to use models to figure out what happens from here. There are the optimistic scenarios wherein we still have some time (about 10 years) to do something and where the consequences gradually build in severity over the next 50 years. In these optimistic scenarios we are faced with major economic and environmental consequences, some of which have started, but they will build gradually and we still have time to adjust. The most pessimistic scenarios suggest we are screwed already, that we missed our window of opportunity and we will see a sudden, discontinuous “tipping point” which will be dramatic and will kill many, many people. The respectable global warming skeptics do NOT question that it is happening, they question these most pessimistic scenarios.

The change in sea levels is at an earlier stage and not as certain. What is certain is that warming, for several reasons, WILL raise sea level. There is both thermal expansion (warm water takes up more space than cold water) and melting ice sheets adding more water to the oceans. But what stage we are at in that process is not certain.

So when you hear these two “objections” to global warming, and I strongly suspect you will, realize that they are red herrings. They ask legitimate questions that just happen to have nothing to do with the CHANGES that are occurring.

For those who want some raw data, you can get them right from NASA here: http://data.giss.nasa.gov/gistemp/

For those who want some digestion of the raw data, one of my climatologist sources recommends reading this Wikipidia entry:
http://en.wikipedia.org/wiki/Temperature_record

And for the data on sea level changes, you can go to the University of Colorado, Boulder’s website: (notice the Y-axis in the main graph is the CHANGE in sea level, not absolute sea level).
http://sealevel.colorado.edu/

The NASS and U of Colorado stuff is right from the experts.

And, as I always say, you can get a good summary of the state of the art, presented for a lay audience, from the Union of Concerned Scientists:
http://www.ucsusa.org/global_warming/

And for some final summaries of what is happening and what we as a society and as individuals can do, you can read John and Teresa Heinz Kerry’s brand new book (now out), reviewed here:
http://culturekitchen.com/node/10327