Tamino posted the monthly anomaly graph below purportedly showing that snow cover is on a linear decline.
http://tamino.wordpress.com/2011/03/05/snow/
First problem is that he is running a linear trend line across what is obviously a step function. In the late 1980s there was a step down, and since 1990 the trend is flat to up. The graph below shows monthly snow cover since 1990, which is on a slight upwards trend.
His second problem is that he is mixing apples and oranges. Winter snow cover is indicative of cold temperatures. Winter temperatures across the US, Europe and Asia have gotten colder over the last 20 years. A fact that Tamino and his ilk conveniently and consistently ignore.
By contrast, summer snow cover is indicative of how far north the melt line occurs, which is influenced primarily by the amount soot on the snow. Hansen wrote in 2003 :
Plausible estimates for the effect of soot on snow and ice albedos (1.5% in the Arctic and 3% in Northern Hemisphere land areas) yield a climate forcing of 0.3 Wm^2 in the Northern Hemisphere. The ‘‘ef?cacy’’ of this forcing is ~2, i.e., for a given forcing it (soot) is twice as effective as CO2 in altering global surface air temperature. This indirect soot forcing may have contributed to global warming of the past century, including the trend toward early springs in the Northern Hemisphere, thinning Arctic sea ice, and melting land ice and permafrost.
Temperature Change Due To Soot
Then Tamino chimes in with the Master’s junk science claim about winter snow :
What does the physics say? To have snow, you need two things. First, cold air — but not too cold. Second, you need moisture.
Global warming affects both. It increases temperature overall, which, all other things being equal, would lead to less snow. But we should keep firmly in mind that temperature changes won’t be uniform. It’s easily possible (and this winter, actually happened) that some regions will be colder while others are hotter. Especially if the heat goes to regions that are usually extremely cold, while cold penetrates to more moderate regions, that temperature change could favor an increase in snowfall. And that seems to be one of the factors in this year’s heavy snow cover.
Warmists keep trying to blame the heavy winter snow in recent years on warming temperatures, but they never actually look at the winter temperatures to see if it they are increasing. Winter temperatures in the US have been declining at a rate of almost five degrees per century since 1990.
http://www.ncdc.noaa.gov/oa/climate/research/cag3/na.html
h/t to Scott
to compare apples to apples, you would not compare snow to rain…
….you would compare precipitation as water
Hansen should not be quoted on anything, because he is demonstrably incompetent on the greenhouse effect (which has been his premier focus since the beginning of his career):
Venus: No Greenhouse Effect
Hansen got his apocalyptic belief in a runaway greenhouse effect directly from Carl Sagan, and did his doctoral thesis on the Venus atmosphere. Hansen lectures today on the imminent likelihood of a runaway greenhouse effect on Earth, in the most fearful terms. Yet his fundamental incompetence on Venus, nearly 20 years after the Magellan mission returned the detailed data that simply invalidates his belief, is indefensible. In my current understanding, the Venus/Earth data negates all belief in the radiative transfer theory as currently applied in climate science, and all talk of radiative forcing of atmospheric temperature should be considered highly questionable.
I’ve read a couple of your articles on this Harry and I’m with you all the way.
Hansen has been barking up the wrong tree all his career.
Keep the good work coming.
That’s the same type of game warmists play with stratospheric “cooling” by employing a “long term” trend which includes two volcano (Pinatubo and El Chrichon) events, yet since ~1994 without volcanoes the stratosphere has been warming.
Tamino is fond of using even the most crass charting tricks to deceive his readers. He represents the damage control wing of the PR machine that made the Hockey Stick. His role is to remove doubt in those who lack their own analysis and charting tools. Here is my moderated out single glance debunking of his use of smoothing filter end effects and cherry picked end dates that allowed him to turn the highly inconvenient CET (Central England Temperature) record into a Hockey Stick: http://oi49.tinypic.com/r245ex.jpg
None of these charts or any interpretation of them shows anything that looks like a threat to Western Civilization or the nightmare sci fi scenarios that have been slobbered by “experts” lately.