Admittedly, from 2004 to late 2007 we saw a big decrease in ice levels, however no doubt thanks to some record cold temperatures and record snow levels of late, the global sea ice levels have increased to very high levels.
So should we be worried about global ice melting. Once again I'll show the graph, because it clearly says "no".
10 comments:
What is remarkable is the speed with which sea ice cover has increased over the last couple of months. We will have to wait and see whether this is just a short term, albeit large, anomaly or we are seeing the start of a trend.
2008 looks like being a very interesting year climate-wise - la nina continues to strengthen, sun spots continue at a minimum and the PDO has gone negative.
Quote: "there is currently around 1 million squared kilometers of ice on the worlds surface than normal."
Do you mean 1m Km2 _MORE_ ice on the worlds surface than normal? Is there a word missing or is the 1m Km2 of ice about the normal amount?
yep, Do you mean 1m Km2 _MORE_ ice on the worlds surface than normal,
I shall fix.
Jonathan: are the data sufficiently comprehensive to allow for a regional breakdown? I ask because the records do show a significant decrease in arctic ice cover, which leads me to believe that there must be an increase in other regions to increase the mean.
john Smith, the recent increase has been about equally in the NH and SH. However in the NH it was from a large negative anomaly.
And note the 1M sqK anomaly is relative to the 'long term' average. The actual increase in sea ice over the last 3 months is closer to 3 million sqK.
To appreciate how large this increase is, you need to understand that total sea ice in both hemispheres is around 17 to 18 million sqK throughout the year. So the recent increase is of the order of 15%.
As I said earlier, It remains to be seen whether this is a short term anomaly or the start of a longer term trend. But it is a very large and rapid increase and IMO, at least in part, represents a trend.
This is perplexing. As I read the plot the current level is about 1M km2 below the average, not above it. And I can easily see a downward, not upward, trend over the short period plotted. That's easier to see if you squash the plot until it is square instead of stretched way out horizontally.
I can't imagine how you get your interpretation of this. Clue me in...
Perhaps if the data were in more graphical form, it could be seen better. Try here:
http://www.nrdc.org/globalwarming/qthinice.asp
If I'm not mistaken there is 20% less ice now than in 1979, at the summer minimum for both periods.
Hi Tom,
probably because the article was written in Jan 2008, 2 years ago.
Ha! I didn't notice that the plot was updating beyond the message date.
So you do understand the difference between weather and climate, right? The trend line through the data, or a running average over a time longer than the cycles in the series, is what really tells the tale. And such a trend would to me clearly be downward over the period plotted.
100% Tom. I've even commented how it looks like from about 2004, it looks like there has been a decrease in global sea ice, that despite a very large variance.
Its a pity we dont have data going back to 1900 about this tho, or even back to 1500
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