You don't need a p value to see that 2016 is a striking outlier.
Note this is a graph of sea ice, not land ice, and that it includes both arctic and antarctic ice, which is why it doesn't have a unimodal curve. More info at the National Snow and Ice Data Center.
A related story from Wisconsin:
The Wisconsin Department of Natural Resources recently scrubbed language from an agency web page on the Great Lakes that said humans and greenhouse gases are the main cause of climate change.Don't blame the staff at the Department of Natural Resources. This change in language was mandated by Governor Scott Walker.
The DNR now says the subject is a matter of scientific debate.
The department made the changes on Dec. 21, striking out whole sentences attributing global warming to human activities and rising levels of carbon dioxide.
It’s the most recent example of the DNR removing information related to climate change. More broadly, the changes reflect how the administration of Republican Gov. Scott Walker has de-emphasized the subject since he took office in 2011.
In the latest changes, the DNR says of climate change, “as it has done throughout the centuries, the earth is going through a change. The reasons for this change at this particular time in the earth’s long history are being debated and researched by academic entities outside the Department of Natural Resources.”
I'm puzzled by the plot. Why would sea ice go down in Winter? Presumably this is because it's summer in the antartic. But then when you think about that you realize what this plot is showing may be more complex than one was intially thinking. Sea Ice should go up and down but not simply like winter/summer. So while one can say something is different it's not clear what to conclude about it. good? bad?
ReplyDeleteRemember that the sea ice in the Antarctic region is way bigger than that in the Arctic, so the two fluctuations do not simply cancel one another out. And the peak and trough times at each pole don't correspond to the midpoints of the seasons, so it is a complex matter.
ReplyDeleteYou know, I really don't trust the chart you have posted. Go to the US National Snow & Ice Data center run by NOAA, NASA and the NSF. Their interactive polar sea ice data page is at http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
ReplyDeleteNote: you need to toggle it to see Arctic and Antarctic data.
From the above chart as posted, sea ice is down something like 4-5 million km^2 in September from the average. However, if you look at the NSIDC data page I'm seeing maybe 2 Million km^2. I suspect the data as show on TYWKIDBI is incorrect, as put together Wipneus.
When in doubt, go look at the source...
Oh yeah.. that chart is hosed.
ReplyDeleteTurns out you can pull data points off the Chartic interactive plot at the NSIDC. Just as a check I pulled the data for Sep 15 (to get near the minimum for Arctic Ice). Chartic gave me (data in millions of square km)
Arctic Sea Ice 4.621
Antarctic Sea Ice 17.881
The total sea is then 22.142 Million Km^2 mid September.
However, the chart from Wipneus is showing around 16.5 M km^2. That's a big difference.....
You (or the two of you, since you're posting anonymously) are comparing two different data sets. The toggled graphs at the link you provide show data on sea ice EXTENT. The one in my post is for sea ice AREA. They are not the same.
ReplyDelete"The ELI5 difference is, "extent" tries to measure the total size of partial ice cover's boundaries, including the areas within that aren't covered, while "area" tries to only measure the actual amount of ice cover, excluding the parts that aren't covered."
Via the Data is Beautiful subreddit (https://www.reddit.com/r/dataisbeautiful/comments/5ky8rr/live_chart_of_global_sea_ice_shows_2016_falling/)
Walker is, and always will be, an embarrassment to this state
ReplyDeleteHmm...if you check out the graphs from the following site (https://neptune.gsfc.nasa.gov/csb/index.php?section=234), you will see that the combined sea ice AREA for 2016 is actually much larger than is shown in the graph you have attached (approximately 16.5 x 10^6 km2 for Antarctic at beginning of September and 3.5 x 10^6 km2 for Arctic at beginning of September for a total of 20 x 10^6 km2 at the NASA site versus 16.5 x 10^6 km2 in your attached graph.
ReplyDeleteI would suggest you check the validity of your attached graph...or am I missing something?
Signed...a first-time Anonymous poster
We've officially entered the New Age of not believing anything, even the truth. "Who you gonna believe, me or your own eyes?" ~ Chico Marx
ReplyDeleteAnother data point for comparison..
ReplyDeletehttp://www.climate4you.com/images/NSIDC%20GlobalArcticAntarctic%20SeaIceArea.gif
Global Sea Ice coverage, including both Arctic and Antarctic area (not extent). Indicates in the vicinity of 20-23 Million km^2 global sea ice for the end of 2016, not the ~ 16 M km^2 as cited from the original graph above.