Four weeks of climate data: Arctic Circle Temperature Recap

It's time for a visit from my blog partner, Hypothetical Question Asker.

What do the numbers mean? These are the increases in the median temperatures Celsius from the 1955-1975 era to the 1999-2010 era in these six slices of the Arctic Circle.

Why those years? All four of those years are strong La Niña years.

What's the methodology? Splitting each slice into a 10 × 10 grid and looking for grid points that reported temperatures in at least 90% of the seasons between 1955 and 2010.

Are these numbers big or small? These numbers are hella big, as we say in Oakland. One degree in 56 years is a Big Damn Deal and the smallest number here is 1.38° C.

What's the cause?  In most of the slices, the big change is albedo, areas where ice on the sea surface melts and exposes more water. Losing oceanic ice does NOT increase sea level, but it does mean more heat is absorbed. This is a feedback loop.

What's the main problem? Melting ice caps in the land mass close to the pole, most notably Greenland but also the northernmost islands of Canada.

What do humans have to do with this? Greenhouse gases are our main contribution to the mix as far as the Arctic is concerned. Carbon dioxide (CO2), which is measured in parts per billion in the atmosphere, is at an unprecedented level. The thing is, the earth's climate is a very big thing that doesn't evenly distribute anything.

 If CO2 levels are higher than ever, why aren't temperatures higher than ever? That is a fair question. Not every system increases linearly. For example, gravity increases linearly when mass is increased, but decreases by the reciprocal of the square when distance increases. Other systems only increase by the square root or fourth root of some important variable. The greenhouse gas model hasn't been pushed to this level before, so maybe we will find out a linear increase isn't in the cards. In this case, slower would be better.

Is global warming to blame for Katrina or Sandy or the droughts in the Midwest?  Here, the predictive model doesn't state that exactly. The most that climate scientists can say is the odds of certain things happening seem to be on the rise and that rise is definitely noticeable.  For example, there are events called "100 year storms", based on the idea they can be expected to happen every 100 years. In some parts of the globe, the odds of the "100 year storm" have increased so much that they might now be fairly called "10 year storms" or even "5 year storms".

Later today, a similar recap for Antarctica.

Four weeks of climate data: Arctic Circle recap

We have now looked at three of the six slices of the planet's surface, so this is pretty much halftime in the presentation. I thought it made sense to give a recap of the data so far, starting with the Arctic Circle.

Arctic Circle Region #1

Confidence of the region warming: 99.8%
Confidence of increasing rate: 97.9%
Change in median temperature from the 1955-1975 interval to the 1999-2010 interval: 1.55° C

When numbers are in bold, this means they are significant. Rising more than a degree in about 56 years is serious.

Arctic Circle Region #2


Confidence of the region warming: 99%
Confidence of increasing rate: under 50%

Change in median temperature from the 1955-1975 interval to the 1999-2010 interval: 2.19° C

Arctic Circle Region #3

Confidence of the region warming: 97.7%
Confidence of increasing rate: 99.7%
Change in median temperature from the 1955-1975 interval to the 1999-2010 interval: 2.91° C

Arctic Circle Region #4

Confidence of the region warming: 99.9%
Confidence of increasing rate: at 50%

Change in median temperature from the 1955-1975 interval to the 1999-2010 interval: 2.36° C

Arctic Circle Region #5

Confidence of the region warming: 99.9%
Confidence of increasing rate: 65%

Change in median temperature from the 1955-1975 interval to the 1999-2010 interval: 1.94° C

Arctic Circle Region #6

Confidence of the region warming: 95%
Confidence of increasing rate: 65%

Change in median temperature from the 1955-1975 interval to the 1999-2010 interval: 0.83° C

The big takeaway: The Arctic is warming like crazy. The worldwide change in temperature in this era is less than a degree. In the Arctic, only Greenland is warming that slowly.

My first hypothesis was about people and the relative lack of them in Greenland.  The real difference is albedo, the difference between ice reflecting heat and water absorbing it. The Greenland ice layer is much more constant that the ice sheet on the Arctic Ocean.

Thursday, a re-cap of the Antarctic, a place like Greenland but more so, a massive ice sheet mainly lying above solid ground.

Four weeks of climate data:Arctic Circle Region #6

So far, we have had five slices of the Arctic Circle and every one has shown a warming trend over the time period 1955-2010. The last slice is polar Greenland, which excludes only a small part of the large island, a little in the south and the western part that counted in the previous polar region.

Greenland has a lot of land north of the Circle, but that land is extremely sparsely populated and very poorly covered by weather stations. There are seven grid points out of a possible 100 that give readings.

Looking at the Winter data, no trend is consistently upward, though the most recent time interval is clearly warmer than the last. The record warm Winter was about 30 years ago.

Spring also shows no trends. The null hypothesis for warming has to be "there is no warming" and the null hypothesis for an increasing trend has to be "there is no increasing trend". Both Winter and Spring data point to keeping the null hypothesis, or saying it in the technically proper statistical weasel words, "so far, we fail to reject the null hypothesis".

Greenland Summers say the same thing. The highs and lows bounce around the way random stat with no discernable trend would do.

Finally, a sign of a warming trend shows up in the low temperature pattern in Fall and in the median, just barely enough to overwhelm the data pattern we have seen.

We can say with just barely 95% confidence that the weather in Greenland is warming. Compared to the other five sections, the weather in Greenland appears to be relatively stable over this period, rising on average less than a full degree Celsius from the median reading of 1955-1975 to the most recent interval, 1999-2010.

Final Arctic tally

Warming regions: 6-0
Increasing trend regions: 2-4

A fair question is why Greenland is the odd region out in the Arctic. A big difference is a land mass with a very large ice cap. Bright colors like ice reflect heat and dark colors like sea water absorb it. This effect is called albedo. In Antarctica, a lot of the slices will be filled with ice covered land mass and some ice shelves above what would be open ocean if the ice weren't there.

Four weeks of climate data: Arctic Circle Region #5

The final two regions of the Arctic Circle have a lot more land mass than any of the first four regions, though not quite as much population as Region #1, which encompasses polar Scandinavia and northwestern Russia. Region #5 is dominated by the Queen Elizabeth Islands, and we should expect a lot of weather stations relatively close to the North Pole.

We expected them and here they are. Each square represents a grid that get included in our regional average. The ones with thicker outlines get data from all or nearly all seasons in the time span we are considering, 1955 to 2010, years chosen because they were both years with strong La Niña currents. We split this era into four intervals based on Consistent Oceanic Niña Intervals.

First interval: 1955-1975
Second interval: 1975-1988
Third interval: 1988-1999
Fourth interval: 1999-2010

The black line at the top follows the record warm temperatures in the four intervals. It looked like a static trend or slight cooling in the last half of the 20th Century, but a big jump up in the 1999-2010, which would say warming and an increasing warming rate of warming.

The red line is the median. Again, the first three eras have a static pattern and the last time intervals shows warming and an increasing rate.

The bottom black line follows the coldest winters in each time interval. There was a warming jump between the 1975-1988 and the 1988-1999 eras, but a slight decline in the most recent. The general trend here would say warming but the rate is not increasing.
 

Every indicator for Spring says a warming trend a step up every time.  The high and low average temperature trends say an increasing rate, but the median does not.

Summer's trends are not as unanimous as Spring's in terms of warming, with little up-down-up stutter steps breaking up the median readings and the highs, but there is no compelling argument this is showing static data, it's clearly warming.  As for an increasing rate for warming, the median says yes and the other two indicators say now.

Fall data also convincingly argues for warming and the median and low trends argue strongly for an increasing rate, while the record high trend is not as clear.

Warming trend: 11 indicators say yes, 1 is uncertain. The ayes have it.

Increasing rate warming of warming: The split is much closer 7 yes to 5 no.  While there is a majority, it is not convincing, so over all seasons we cannot say the rate of warming is increasing.

Warming regions: 5-0
Increasing trend regions: 2-3

Later today, a look at last slice of the Arctic Circle, which encompasses almost of Greenland and nothing else.

Four weeks of climate data: Arctic Circle Region #4

We are now looking at the Western Hemisphere regions of the Arctic Circle for the first time. Lots of open water, very little land, all of it as far from the North Pole as you can get and stay in the Arctic Circle.

We think of Alaska as a huge ice box. It's Fort Lauderdale at Spring Break compared to most other Arctic regions.

Not surprisingly, the only grid points that have strong coverage are in the southern part of the Arctic Circle.

In the Winter months, there was a big jump in the 1970s, a static period until the turn of the century and then a small warming trend recently. I would say this is warming but definitely not getting warmer faster.

In the Spring months, the big jump is in the 1980s and 1980s, the era that had cool Winters. Go figure. I'd still argue a warming trend of sorts, definitely not an increasing warming trend.

Summer has that upward step pattern in all three measurements, record highs, record lows and median for the Consistent Oceanic Niña Intervals. Definite vote for warming, definite vote against it getting warmer at a faster rate.

The Fall data also argues for a warming region and makes an argument for the warming trend increasing. It helps win the first argument, it's definitely a warming region, but it loses the second one, the rate of increase isn't getting faster here over most the seasons.

So this region has to be counted as warming but not increasingly so.

Warming regions: 4-0
Increasing trend regions: 2-2

Tomorrow, we finish the Arctic data with the region dominated by the Queen Elizabeth Islands and the final region, encompassing the lion's share of Greenland.

There are lions in Greenland? I swear, nobody tells me anything.
 

Four weeks of climate data: Arctic Circle Region #3

The third slice of the Arctic Circle is polar Siberia. It does not have the land mass of the previous Russian slice and there are less readings, but still enough data to get a fair idea of the trends.

The readings are mostly on the mainland, but the northernmost grid square comes from the islands known in Russian as Severnaya Zemlya.

The Winters in the last half of the 20th Century were fairly static, but the most recent interval shows both a warming trend and an increasing warming trend.

One very warm Spring in the 1980s makes the new record look unimpressive, but the median jumped over two degrees in the most recent interval compared to the 1988-1999 range.

Again, this shows warming and increasing warming.

If we just look at record highs, the 21st Century time interval looks to be cooler that the 1988-1999 era, but the median and the lowest trend both argue for warming and increasing warming.

The fall shows warming and increasing warming. The median rising over 4 degrees Celsius is a startling change.

So this region has to be counted as warming and increasingly so.

Warming regions: 3-0
Increasing trend regions: 2-1


Later today: Arctic Region #4, with parts of Russia, Alaska and Canada.

Four weeks of climate data: Arctic Circle Region #2

Our second slice of the Arctic Circle is the first all-Russia region. It has more land mass than any other slice of the Eastern Hemisphere and islands above the 80th parallel.

We don't expect anything like 100% coverage in the Arctic, but these grid points include several that are farther north that we saw in region #1.

The Winter data does not make a convincing argument for a warming trend, even though the median ticks up slightly each time interval. It certainly is not getting warmer faster.

Spring on the other hand does show a warming trend in every statistic, record highs, record lows and medians. Once again, it is not getting warmer faster.

Summer also argues for a warming trend but against an increasingly warming trend.

The fall median says warming and slightly increasingly so. It gets voted down by the other three seasons on the increasing part. The low temperatures argue for increasing. The high temperatures would say static, but really, all that high temperature mark says is there was one freakishly warm Fall in the 1960s. There are five Fall temperatures in the Oughts warmer than the second warmest temperature in the Sixties.

Three out of four seasons argue for a warming trend, a different three of four say it's not getting warmer faster.

Warming regions: 2-0
Increasing trend regions: 1-1

Tomorrow, the last Eastern Hemisphere slice and the first Western Hemisphere section, as we say do svidaniya to Polar Russia and "Good day, eh?" to the Canucks, with just a second to shoot a quick wink and a "You Betcha!" at Alaska.
 

Four weeks of climate data: Arctic Circle Region #1

For the Arctic, this is a highly populated area, especially northern Scandinavia.

The blue diamonds are the corners of our region, the upper left diamond is the North Pole. Most of the grid points covered are in the south. All grid points are treated equally if the give at least one reading in a season, but the ones with thicker borders gave readings in all the seasons. The minimum number of readings to qualify is 75%.

Each graph shows the yearly temperature fluctuations. In Winter that line's color is blue. The three other lines are the high median and lowest temperatures in each of our Consistent Oceanic Niña Intervals, 1955-1975, 1975-1988, 1988-1999 and 1999-2010. The low temperature line shows a clear warming pattern, every step higher than the last. The median, shown with the red dotted line, is less conclusive with one dip down, a big tick upwards and flat line between this century and last. The high temperatures show a rise in the record warm Winter, but the rise is small.

Conclusion: Rising, but not rising at an increasing rate.

Spring's data is a little more convincing of a rising trend, especially after 1975, and the median argues that it is rising at an increasing rate.

Summer data more or less mimics Spring. This looks like a warming region and the rate jumped by more than usual.

Until 1999, this region looked to be static, but then there was a big jump. I am categorizing this one a warming region and an increasingly warming region.

Later today, Region #2.

Four weeks of climate data:Six regions for the Arctic Circle

And it starts all over again.

We start with the Arctic Circle, defined by the tilt of the earth, the region that experiences six months of darkness and six months of light each year, with the light and dark split getting more pronounced the farther north you travel.

It struck me that I could get through the data faster by splitting some latitudinal slices into six regions instead of twelve. The tropics and the polar regions take up less latitude than the temperate, so I will still be splitting the temperate zones into twelve parts, but the polar and tropical into six. The first slice is the polar part of Europe and a few Arctic islands.

Next is the second region, the central Russian polar section, again with some large Arctic islands.

The third region is polar Siberia.

The fourth region gets us to the Western Hemisphere, with parts of Russia, Alaska and Canada.

The fifth region is almost entirely Canadian with just a small slice of Greenland. Most of the land mass is made up of the Queen Elizabeth Islands.

The final region, as luck would have it, is almost all of polar Greenland.

Later today, we will be looking at the first two regions. At two regions a day, we will be finished with the Arctic this weekend and start looking at Antarctica on Monday.

Stay tuned.