Is Global Warming Real? Evidence: Snow Cover
81Snow cover has steadily declined across the Northern hemisphere in the past 40 years, providing strong evidence for global warming.
Thanks to the media frenzy over climategate, it seems that many people believe global warming is one big hoax. Is this true?
What's the evidence that the earth is warming?
This is the second hub in a series about the evidence for global warming. The first hub, Is Global Warming Real? The Evidence Part I: Global Temperatures examined global temperature data. The next hub looks at Arctic sea ice.
Global temperature data is not the only evidence we have that the earth is warming.
The image above is a graph I created using data from Rutgers University Climate Laboratory. It shows the yearly average (mean) snow cover for the northern hemisphere.
Most of the decline is seen during the summer and spring - winter and fall snow cover seems to be holding steady.
Perhaps NASA and NOAA and CRU Hadley, who keep global temperature records, are untrustworthy. Is Rutgers University in on the conspiracy too?
Well, the University of Illinois also studies global snow cover. Here's what they have to say:
The 28 year trend in snow extent derived from visible and passive microwave satellite data indicates an annual decrease of approximately 1 to 3 percent per decade with greater deceases of approximately 3 to 5 percent during spring and summer. Precipitation in regions of seasonal snow cover appears to be constant or increasing slightly in some locations over the same time period, which suggests that diminishing snow cover is the result of increasing temperatures. One region where the snow appears to be diminishing rapidly is the Western United States, especially in spring when the duration of snow cover has been decreasing by 2-3 days per decade (see blue-colored areas in the Spring Duration figure). This satellite-derived trend agrees with direct measurement of snow depth and extent on the ground (Mote et al. 2005).
The Canadian Cryospheric Information Network also shows declines in snow cover. Direct observations since 1955 have shown that the first snow starts later, the first melt starts earlier, and the depth of snow is decreasing (click here for a table).
Data from the Australian Government also show a decline in snow cover in Australia.
Norwegian data also shows a clear decline in the length of the snow season and depth of snow cover in Norway.
Snow cover in China presents an interesting exception - without disproving the theory. Annual snowfall and and extent seems to have increased, overall, in China. But it is interesting to note that "The time series analysis over the past 30 years shows that the annual snowfall amount, as well as the winter cumulative snow depth, is positively correlated with the global mean temperature, increasing during warming periods and decreasing during cooling periods."
In other words, increased snowfall in China indicates rising temperatures. Quoted from this paper by Li Peiji of the Lanzhou Institute of Glaciology and Geocryology, Academia Sinica (PDF).
China's example illustrates the difficulty in using snow cover data to prove global warming. In many areas, increased warming is expected to lead to increased precipitation - which will lead to deeper snow. In other areas, local climate patterns will dry out and warm up, leading to less snow cover.
So declines in snow cover is not conclusive proof of global warming.
But this is not the only evidence that the earth is warming. There is more evidence to come in the next hub: Is Global Warming Real? Here's the Evidence, Part III: The Arctic Ice Cap.
- (PDF) Northern Hemisphere snow extent trends derived from visible and microwave satellite data
- (PDF) Global snow extent climate data records and trends derived from satellite passive microwave an
- Seasonality and trends of snow-cover, vegetation index, and temperature in northern Eurasia.
- World Climate Report Tread Carefully on Snow Cover
- Will Climate Change Affect Snow Cover Over North America?
The predicted decrease in this integrated hydroclimatological metric suggests a strong and persistent climate change response at the land surface, which could have considerable impacts of water supply, ecological cycles, recreation, and subsequent cl
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Kate - thanks for the comment. You illustrated some of the difficulties in using snow cover as an indicator for global warming! Off the top of my head I think that the Western US is seeing less precipitation but not sure. I'll have to research that.
Of course there are other indicators, which I will be covering in upcoming hubs.
As for global temperatures, most of the global temperature stations measure surface temperature and lower atmospheric temperature. There are variations in atmospheric temperature depending on what layer of the atmosphere we are talking about.
You've given me some questions to think about - maybe this will turn into another hub! Thanks for stopping by.
Good work!
Thank you Ralph!
Now Sarah Palin is debating Al Gore - I mean really!!!
you might be interested in this. This scientist is threatening to sue NASA
http://www.youtube.com/watch?v=A-uAwbkIUoM
21 cm of snow in copenhagen
NASA (James Hansen) tried to rewrite history by eliminating "Climate Optimum" http://en.wikipedia.org/wiki/Holocene_climatic_opt
Heh. Chris Horner is not a scientist, he's a lawyer. He works for the Competitive Enterprise Institute:
http://www.sourcewatch.org/index.php?title=Chris_H
"Christopher C. Horner is a senior fellow at the Competitive Enterprise Institute (CEI), a think tank that's received more than $2 million in funding from ExxonMobil since 1998, among other corporate funders. [1]"
well that's true. but the other scientists weren't working for pennies either.
you might want to research Milankovitch cycles as that does explain changes in temperature due to changes in the Earth's orbit.
BTW, al Gore isn't a scientist either, but he stands to makes millions in carbon trades
the guy who shared Al Gores Nobel is Dr Rajendra K. Pachauri, and he is an economist, who stands to make a windfall in carbon trades, from his association with The Tata Group in Mumbai.
Whatever the reason for global warming ,it seems evident that it exists.Of,course Al Gore has his own reasoning as to why and what we should do about it.My hope is some of the new energy inventions that I keep hearing about get enough funding to make them a reality in the marketplace.
Like cold fusion,as well as others.Wind and water,and solar power generation continue to be pushed as the only green alternative energy technologies when I know for a fact,that there are others,that are even more promising if they will get the chance to prove themselves.
good job, william.
you're amassing a ton of data, and i'm enjoying this series you're putting together.
Vraj - I know all about Milankovitch cycles. So do the climate scientists who have advanced degrees and make a living studying this stuff. They are not enough to explain the current variation.
Try listening to scientists, not lawyers. And you'll notice I haven't quoted Al Gore in any of my hubs, please leave him out of this.
Someonewhoknows: thanks for dropping in. You are right, if we would just change our energy sources global warming would be a moot issue. Too many entrenched interests to make that easy though. Nuclear energy industry vs. the coal industry vs. the wind industry vs. the coal and gas industry vs. the burgeoning biofuel industry - all of them lobbying in Washington and cutting each others throats. And nothing is getting done.
Thank you Bluedog!
Great job, William. I'm a little torn on the snow data, though.... cause I hate the stuff! LOL
Indeed reports from where I live down here show reduced cover in the snowfields in Australia in winter from those that have lived and worked in them for decades...
For Vrajavala and anyone else interested in Milankovitch cycles:
Big thanks Carolina Muscle!
Hey Barry, thanks for dropping by. The ski industry in Australia is going to have a tough time looks like.
Thanks for telling the truth with some hard data. People don't realize how dangerous these rising sea levels are. They make tschunamis more possible.
Thank you Writer Rider!
What are your thoughts on Global Dimming?
Hi OD,
I don't so much have an opinion, per se, on global dimming. As I understand it, the term refers to a sort of darkening of the atmosphere by soot. The more soot is in the air, the less sunlight reaches the surface, resulting in cooler temperatures.
As humans started burning more fossil fuels, the levels of soot and the levels of CO2 both increased. There is some speculation that certain laws passed in the US and other countries to reduce soot pollution will actuallly exacerbate global warming by removing the source of 'global dimming'.
China, it seems, is still producing a great deal of soot so they could be bringing global average temperatures down significantly.
Great hub again William. It's very easy to see the reduced snowfall here in New Zealand. Just go to our South Island glaciers. The face of the glacier is several kilometres back from where it was 50 years ago on both the ones I have seen. As one drives to the face you pass several 'viewing platforms' that no longer have a view of the glacier
Thanks William, I have to agree with your comments.
And China with its population size and manufacturing domiinance, they could turn the tide from warm to cold.
Thank you Cally - that is a pretty amazing example of global warming in action!
Opinion Duck - most of the problem in dealing with global warming and all environmental issues, it seems to me, is because these are global issues. If China does something but the US doesn't, then not only do they cancel out the environmental benefits but one might gain an unfair advantage. It's a tough and complicated situation.
I haven't been following the Copenhagen stuff very closely but I read that the poorer nations all walked out because the rich nations weren't going to live up to earlier promises. Seems like a solution will not come from big multinational treaties.
It seems fairly clear at this point that our species is determined to push itself back into the stone age. Fine. Let Nature take its course. Perhaps the legend of the Phoenix has some relevance.
Another possibility of course is our extinction. This might also be appropriate. It was after all, the extinction of the dinosaurs that permitted the ascendancy of the mammals. Perhaps it is time for us to make way for other species to evolve. Perhaps the next dominant life form will find a way to be "successful" without terminally fouling its own nest.
" They have pillaged the world. When the land has nothing left for men who ravage everything, they scour the sea. If an enemy is rich, they are greedy; if he is poor, they crave glory. Neither East nor West can sate their appetite. They are the only people on earth to covet wealth and poverty with equal craving. They plunder, they butcher, they ravish, and call it by the lying name of "empire." They make a desert and call it "peace"."
--Roman historian Tacitus
Wow CWB - great quote.
Real History, William, can be a real eye-opener.
I have been reading up on some data about how there is a possible up and down cycle, driven by greenhouse gasses and volcanic ash.
In the past volcanos have spewed forth enough ash & sulphuric gasses to actually cool the globe for several years. Since we have had some major eruptions in the past three decades, which seems to be the time when some contend that the globe has actually cooled at times, a few researchers are looking into a tug-of-war effect between the contending atmospheric upsetters - volcanoes vs. greenhouse gasses.
Volcanos were believed responsible for the year without summer back around 1815 or so, and recent research from Iceland shows that volcanic eruptions there also cause widespread cooling at other times in Europe's past.
Just the same, global climate change is occurring, no matter the cause, and I agree with ColdWarBaby that we often seem to move ahead, often out of greed, and we say damn the consequences, full speed ahead.
Somehow we have come to the conlcusion that corporate greed benefits us in some strange way. Yes, we may get a job because of it, but we are still pawns in the larger sense of things. Corporations do not have a soul or a heart: they exist solely to make a profit often with no regard for the actions they take or the messes they leave behind.
Chef Jeff
Thanks for the comment Chef Jeff. Climate is definitely complex. Soot from fossil fuels also plays a role in both warming and cooling. Soot blocks sun and cools some regions. In snow covered areas, however, it darkens the snow surface, causing it to absorb more heat and thus melt faster.
We certainly don't understand everything about climate.
It's all gone quiet here now, hasn't it?
How so, Mr. Lol?
There is no doubt that greenhouse gasses are rising since the industrial revolution, and there is no doubt that greenhouse gasses cause a rise in global temperatures.
After that, there is a lot of speculation. It is a tremendously complicated endeavor to try to determine even correlations between greenhouse gasses and climate events, much less any causation.
Question is, do we anticipate worst-case or best-case scenarios? What is the prudent course of action?
(Denial is not a prudent action)
Anticipating the worst case scenario may not be enough. The nuclear reactors at Fukushima were designed to withstand the earthquakes and tsunamis that were thought likely to occur - and look what happened.
You are right that there are a lot of unknowns and variables. But - keep in mind that one indicator of global warming, arctic ice cover, is declining much faster than even the worst case models predict.
Lives are at stake. It would be foolish not to plan for the worst. If the best case scenario happens, we can laugh at our luck.
Thanks for commenting Winston.
kateperez Level 3 Commenter 2 years ago
Do you have measurements on the amount of precipitation as well?
It seems if there is not as much precipitation that there will be not as much snow. I know that many parts of the US have been feeling drought-like conditions, and it has snowed more in the past 2 years in Houston than it has snowed in the past decade.
I still contend that the problem is not greenhouse gasses but rather the Earth has changed its axis and is re-adjusting to different absolute north and south poles. I remember hearing that the tsunami that took out that asian island knocked the Earth off its axis. Is it possible that it never recovered accurately?
I am opposite you on the global warming idea. I do not believe it is accurate. Do greenhouse gasses limit the snowfall? If Earth's temperature has been cooling then it seems to me that is different than snowfall measures. One is land temperature and the other is atmosphere temperature. What do they classify global warming as? Temperatue of the planet or of the air?
Good article. I just have a differing viewpoint.
Thanks! I really did like reading a logical and non-insulting viewpoint.
Kate