Guest post by Steven Goddard
Several people keep asking why am I focused on winter snow extent. This seems fairly obvious, but I will review here:
- Snow falls in the winter, in places where it is cold. Snow does not generally fall in the summer, because it is too warm.
- Winter snow extent is a good proxy for winter snowfall. Snow has to fall before it can cover the ground.
So what about summer snow cover? Summer snow cover declined significantly (from the 1970s ice age scare) during the 1980s, but minimums have not changed much since then. As you can see in the graph below, the overall annual trend since 1989 has been slightly upwards.
Data from Rutgers University Global Snow Lab
Note in the image above that there has been almost no change in the summer minimum snow extent since 1989, and that the winter maximums have increased significantly as seen below.
Summer snow cover is affected by many factors, but probably the most important one is soot, as Dr. Hansen has stated.
The effects of soot in changing the climate are more than most scientists acknowledge, two US researchers say. In the Proceedings of the National Academy of Sciences, they say reducing atmospheric soot levels could help to slow global warming relatively simply. They believe soot is twice as potent as carbon dioxide, a main greenhouse gas, in raising surface air temperatures. … The researchers are Dr James Hansen and Larissa Nazarenko, both of the Goddard Institute for Space Studies, part of the US space agency Nasa, and Columbia University Earth Institute.
http://news.bbc.co.uk/2/hi/science/nature/3333493.stm
The global warming debate has until now focused almost entirely on carbon dioxide and other greenhouse gas emissions, but scientists at the University of California – Irvine, suggest that a lesser-known problem – dirty snow – could explain the Arctic warming attributed to greenhouse gases….The effect is more conspicuous in Arctic areas, where Zender believes that more than 90 percent of the warming could be attributed to dirty snow.
http://www.scienceagogo.com/news/20070506202633data_trunc_sys.shtml
In summary, winter snowfall is increasing and currently at record levels, and summer snow extent is not changing much. Earlier changes in summer snow extent were likely due primarily to soot – not CO2.
Why Is Winter Snow Extent Interesting?
Several people keep asking why am I focused on winter snow extent. This seems fairly obvious, but I will review here:
1. Snow falls in the winter, in places where it is cold. Snow does not generally fall in the summer, because it is too warm.
2. Winter snow extent is a good proxy for winter snowfall. Snow has to fall before it can cover the ground.
So what about summer snow cover? Summer snow cover declined significantly (from the 1970s ice age scare) during the 1980s, but minimums have not changed much since then. As you can see in the graph below, the overall annual trend since 1989 has been slightly upwards.
Data from Rutgers University Global Snow Lab
Note in the image above that there has been almost no change in the summer minimum snow extent since 1989, and that the winter maximums have increased significantly as seen below.
Summer snow cover is affected by many factors, but probably the most important one is soot, as Dr. Hansen has stated.
The effects of soot in changing the climate are more than most scientists acknowledge, two US researchers say. In the Proceedings of the National Academy of Sciences, they say reducing atmospheric soot levels could help to slow global warming relatively simply. They believe soot is twice as potent as carbon dioxide, a main greenhouse gas, in raising surface air temperatures. … The researchers are Dr James Hansen and Larissa Nazarenko, both of the Goddard Institute for Space Studies, part of the US space agency Nasa, and Columbia University Earth Institute.
http://news.bbc.co.uk/2/hi/science/nature/3333493.stm
The global warming debate has until now focused almost entirely on carbon dioxide and other greenhouse gas emissions, but scientists at the University of California – Irvine, suggest that a lesser-known problem – dirty snow – could explain the Arctic warming attributed to greenhouse gases….The effect is more conspicuous in Arctic areas, where Zender believes that more than 90 percent of the warming could be attributed to dirty snow.
http://www.scienceagogo.com/news/20070506202633data_trunc_sys.shtml
In summary, winter snowfall is increasing and currently at record levels, and summer snow extent is not changing much. Earlier changes in summer snow extent were likely due primarily to soot – not CO2.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
As you can see in the graph below, the overall annual trend since 1989 has been slightly upwards.
And what is R^2 for that graph?
Quite possible, however temperatures seem to be falling on landmasses as well and so the soot problem might turn out to be a good thing.
Just to be clear and avoid getting off on irrelevant tangents, snow cover did decrease from 1970 through 1989. Winter snow cover has returned to the unusually high levels of the 1970s. Summer snow cover has not returned to 1970 levels, but has not declined since 1989.
It is interesting how Henson tries to do the global warming spin.If the first theory doesn’t work then change theory.Folks these people could care less about what is really happening .The planet is cooling .But this goes against thier theory and goverment control.
Could we get a close up view of the summer snow extent, like we did for the winter to see what tend looks like over the same period?
Soot – mostly man made. yet somewhat easy to cleanup. does not stay around for hundred years, washes out with the melting. tackle this first, then see where we are….IMHO
The X axis in the first graph is mislabeled. Are those weeks? Can you show data from 1970 -present?
Is the first graph the one you meant to accompany this post? It doesn’t match the description.
PS. I just woke up, so maybe my brain ain’t workin’ yet.
‘When you’re in a hole, stop digging’ is a sound piece of advice.
Keeps deep frost away from the ground surface. Any farmer will know benefits of the winter snow cover.
We may be reaching a tipping point for the next glacial period. Humans are surely to blame. I just haven’t quite figured out how yet.
So there is more humidity in the Northern atmosphere during winters – so what?
That is doing what in relation to climate change?
It feels like reading the coffee pot – after having had one coffee, only.
Zender had a little lamb,
Its fleece was black as soot.
And everywhere that Zender went,
It’s sooty foot it put.
The 1970s ice age scare caused snow cover to decline??
Leif,
Please feel free to do any statistical analysis you want, and share the results with us. If you want to repeat for the last 10 years that would also be appreciated.
The first graph X-axis shows weeks since 1966. It is pretty easy to pick out winter maximums and summer minimums.
Expanded winter snow-cover must increase the albedo-effect. I’d like to see a discussion by people wiser than myself about what the difference might be.
I have some questions regarding the effect the bounced-back sunlight would have on the temperature of the atmosphere.
I assume that when snow reflects sunlight the sunlight doesn’t change into infrared waves, but remains the same long(?)-wave radiation it was on the way down. Therefore it would not “excite” CO2 on its way out. Is this assumption correct?
Does such long(?)-wave radiation warm the atmosphere at all, as it passes through?
If it does, would not the albedo-effect increase the warming of the atmosphere, because the light would warm on its way in, and also on its way out?
If this was true then, even as expanded snow-cover reflected a lot of heat back into outer space, we might see some slight warming of the troposphere. This might lead to the false impression things were getting warmer, even as we lost a lot of heat to outer space.
Are Oxygen and Nitrogen warmed at all, when sunlight passes through them?
If my ideas are way off base, I don’t mind being educated in the slightest. Thanks in advance.
jj,
Here is the entire Rutgers weekly data set going back to 1966.
https://spreadsheets.google.com/oimg?key=0AnKz9p_7fMvBdHBkREJtSmNlbm9xNnlza0JEcXUwZ2c&oid=2&v=1266508331457
Note the near record maximum on the right edge.
Steve Goddard (07:45:02) :
Please feel free to do any statistical analysis you want, and share the results with us. If you want to repeat for the last 10 years that would also be appreciated.
Come on. You have that data handy. And have software [Excel?] to put in the trend line. Just ask it for R^2 to gain some credibility.
The data start in 1966. So why does your analysis starts in 1989?
I notice that you only cite NH snow extent. What does SH look like?
Does measuring snow extent give any indication of temperature trends in Arctic and Antarctic? Or is this more of a measure of mid-latitude variation?
What would slope for winter snow cover look like without 2010, i.e., how much flatter might it be?
“Christian A. Wittke (07:38:51) :
So there is more humidity in the Northern atmosphere during winters – so what?
That is doing what in relation to climate change?”
The post doesn’t talk about “humidity in the Northern atmosphere”. How do you conclude that the humidity has risen? And while we’re at it, do you think that the mean humidity has risen? The peak humidity? Both? In which layers of the atmosphere? Any idea?
Or have you been confused by The Time with their “In the meantime, warmer air could be supercharged with moisture and…”
at
http://www.time.com/time/health/article/0,8599,1962294,00.html?xid=rss-fullhealthsci-yahoo
(which was pretty hilarious, i mean, SUPERCHARGED WITH MOISTURE. Like, more than 100% – which usually leads to precipitation, even when The Time doesn’t notice.)
Leif Svalgaard (07:16:08) :
I was going to write something about fish and barrels, but the analogy rather breaks down when the fish start shooting themselves.
Snow cover is God’s gift to winter wheat fields. It is so many times better than mere rain fall.
As we read about the permanent dustbowl and reality shows us great ground cover for wheat.
Wheat can grow in the subsoil zones when covered by insulating snow.
Ah ! So the snow was not rotten, ıt was dırty !!
.