I was explicitly talking about escalation of the war in Afghanistan. So I talked about fatalities caused by hostile action in Afghanistan.
If the US quadrupled the number of troops it had in Japan, there would be an increase in the number of US troops killed in Japan, but that wouldn't tell you anything about a war being escalated (since there is no war in Japan to escalate); it would just be evidence that you get more fatal accidents in a country when you have more people in a country. On the other hand, deaths caused by hostile action tells you about how much more intense a war is.
Similarly, whatever happens in Iraq doesn't say anything about what's happening in Afghanistan, and so doesn't say anything about an Afghanistan escalation. It's like saying, "Truman presided over a great reduction in US casualties in Germany, so it's unfair to say he got into a war in Korea". Say what? Again, the point was to show there was a general escalation in Afghanistan, as opposed to a transitory spike during a few specific months.
So, dealing with the real numbers:
US fatalities due to hostile action in Afghanistan under Bush (for simplicity's sake, all from January 2000 through the end of January 2009): 424
US fatalities due to hostile action in Afghanistan in Obama's first term (for simplicity's sake, February 2009 through the end of December 2012): 1,305
(Go ahead, follow the link, use the US filter, the Hostile action filter, and the Afghanistan only filter.)
Hey, guess what? 424Ã--3 is 1,272, and 1,272 is less than 1,305. US fatalities due to hostile action in Afghanistan were more than three times higher in Obama's first term than in all of Bush's presidency. That probably indicates that Obama escalated the war in Afghanistan.