How could anyone possibly know that?
NBC News reports:
According to Hoerling, climate change was likely responsible for “about 3 to 5 percent” of the water vapor in the fetch of tropical moisture, given that a warmer atmosphere can hold more water and published studies indicate “a few percent increase in water vapor to date.”
The rest, he said, is due to atmospheric circulation patterns that appear inconsistent with models used to simulate the global climate, including those being examined for the upcoming report from the Intergovernmental Panel on Climate Change. Those models project a slight decline in summertime rainfall, he said.
This comes from Kevin Trenberth who is quoted as saying that there is now 5% more moisture in the air due to climate change. Logically applied that would impact rain events by 5%. Garbage of course but since KT said it must be true.
I doubt anyone can tell the extra water vapor presence with this kind of precision, nor what affect it had on the rain activity in Colorado. As Brian points out, adding 3% or 5% to a normal year’s rain or to a normal storm would be welcome; it was the other 12 inches that did the damage.
We got a dose of it even here in Montana from that monsoonal flow, which is running kind of late in the season. It’s more often an August phenomenon. We got about an inch in one 20-minute shower and then we got about an inch and a half in 12 hours several days later.
Oh, the silliness. The storm that dumped on Colorado had previously dumped on Arizona. Phoenix got several inches days before the Colo. deluge. Then an unusual set of atmospheric conditions made the storm worse over Boulder. So for nearly a week the storm didn’t move out. It was the remnants of a tropical storm off the Mexican coast that moved north into the Westrn U.S. Only slightly unusual this time of year. And the Southwest has had a vigorous “monsoon” season this year. And we in Arizona are glad for the rain but offer sympathies to the folks in Colorado.
Some areas got almost a years worth of moisture in a few days. That 5% of extra rain would be .7 inches. I don’t think too many people here are worried about .7 inches of rain. Now the other 12-14 inches that fell last week…..
Interesting that these models account for every possibility — drought, flood, excessive regional heat, regional cooling, less snow, more snow, — you name it and it is consistent with the models. Pretty nifty physics!