DISQUS

Michael Tobis Anthropogenic greenhouse warming is not properly a hypothesis, it is an estimated sensitivity. We know that greenhouse gases warm planets. The question is how much *these* greenhouse gases will warm *this* planet. That's a matter of estimation, not of theory. You need to be more specific about the hypothesis before one can be specific about the falsification. This is usually stated as a sensitivty to doubling. The conventional wisdom is near or a little shy of 3 degrees C per doubling of CO2.

So you could talk about evidence refuting a hypothesis that the true sensitivity exceeds 2 C, for instance. Because it is early in the warming process, it would take many years for statistically compelling evidence to emerge if it were true. See:

http://initforthegold.blogspot.com/2008/05/fals...

In particular, the ten year record starting in 1998 is simply cherry picked. A fair look at the data rather than one based in wishful thinking shows that the "cooling phase" is simply an artifact. The world warmed from 1997-2007 in exactly the sense that it "cooled" from 1998-2008; this shows that ten year intervals are not a good way to look at the data. See:

http://initforthegold.blogspot.com/2009/03/and-...

Bob Yes, they have increased.
http://data.giss.nasa.gov/gistemp/graphs/Fig.A2...

Except for 1998, which was unusually warm because of "the El Nino of the Century", note that all the temperatures in this decade (2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008) have been warmer than all the temperatures of the 1990's. Can you follow along so far ?

The CO2 levels, which are the bulk of GHG's, are rising inexorably. They only exceed the IPCC's 'worst case scenario' because the IPCC thought the planet would react more rationally to the problem and start to limit the increase by now, not *increase* the rate of increase. The science remains solid: more CO2 will inexorably force warming of the climate. Which is measured, every decade. Arctic ice cover: measured, every decade, melting away. The models are just there to predict what *will* happen so we have time to take corrective action.

If you plot your annual average of the time it takes you to run 1 mile, vs. your age, it does not necessarily rise linearly, smoothly. One year you might be injured, you have to limp. Another year, you might be training every week, it goes down. But make no mistake, you are getting older every year, your times will rise, and when you hit your 60's, 70's, 80's they will get longer and longer. Eventually you will die. But the curve need not be smooth and linearly rising; that doesn't change the underlying *facts*. Welcome to the messy world of data.