Exactly how much ice is there in the Arctic Ocean?
This may seem to be a fairly straightforward question, but it is amazing how complicated something can become once the media and politicians get involved. Take, for example, the recent announcement by the National Snow and Ice Data Center that the amount of sea ice in the Arctic (that’s the one at the North Pole) was 30% greater in August 2013 than it was in August 2012.
Normally, this would be considered a rather mundane fact, kind of like statistics on the amount of annual rainfall in Reno, NV. (No offense, Reno!) It may be interesting for some meteorologists – whose sole purpose in life is to tell us whether or not it is going to rain and to look good on T.V. – but not for the general populace. (No offense, meteorologists!)
Instead, the extent of ice in the Arctic became a major news item. A flood of articles debated why less of the ice had melted and what the possible ramifications could be. Why? Because as people who have been paying attention for the past few decades know, the Arctic sea ice is supposed to be disappearing. Each year brings new tales of woe: polar bears are dying off, ships are able to sail where they have no business sailing, and Inuit villagers are forced to buy shorts for the first time ever. (Ok, I might have made up that last one.)
Thus, any report that the amount of ice has actually expanded is bound to attract some attention. Fox News posted an article that raised the possibility of “global cooling” before noting later on that the long-term trend was still rather melty. A blogger at the Washington Post countered that assessment with the headline, “Sorry, Arctic sea ice isn’t really ‘recovering’”.
Then I was listening to Rush Limbaugh’s show earlier this week….I will stop there for a moment, because some people might be shocked that I would ever listen to Rush Limbaugh, but I assure you that it does happen from time to time. Anyway, I was listening to Rush Limbaugh, and he was positively giddy with excitement that “Algore” (for he always refers to our former vice president thus, to the point that my sister didn’t know for a few years of her childhood what Algore’s last name was) had been wrong about everything and this proved that climate change was the massive liberal conspiracy he had always said it was. (If Rush does end up in Hell, you can be sure he will be punished by being locked in a room with Al Gore and Gloria Steinem for all eternity, but I digress…)
I think it’s safe to say that this question of ice melt is a highly controversial one. To make matters even more confusing, I have regularly heard people comment that while the Arctic ice might be decreasing, the Antarctic ice is actually increasing. I wanted to investigate the issue and try to find out what is really going on, but the problem is that any source I might use would be considered utterly biased by one side or the other.
Reports by university professors? They are surely made up in order to maintain their professional reputation. Reports by scientists? They are clearly doctoring the numbers in order to get more funding. Reports by political think tanks? They are obviously just trying to please their core constituency. Reports by journalists? Well, who in their right mind trusts journalists?
It seems like such a simple issue: either there is more ice or there is less. When I started writing this article, I had plenty of ice in my drink, but now it has all melted. That is not a value judgment; it is a statement of fact. It also says something about how much time I dedicate to bringing you the best possible information, so in the next few paragraphs, I will attempt to do just that. I cannot remove any doubts about bias, but I can promise you that I will try to get as close to the cold, hard truth as possible. (After all, ice is known for being both cold and hard. Sorry, that is the kind of bad joke you can expect in this type of article.)
As we should all know from our elementary school lessons, water (H2O) comes in three forms: solid (ice), liquid, or gas (water vapor). To get liquid water to evaporate, it must be heated to 212°F/100°C. To get the liquid to freeze, it must be lowered to 32°F/0°C. When the temperature stays below 32°F/0°C, we still have ice. When it gets above that point, the ice starts to melt. However, there are also some geographical factors that impact the shape and character of the ice.
This is a map of the Arctic Ocean. As you can see, it is mostly surrounded by land. When sea ice forms, it only has a limited amount of room in which to spread out, so it tends to be thicker and develop ridges as the ice sheets push against one another.
This is a map of Antarctica showing how it looks in summer and winter. (Remember, summer in the Northern Hemisphere is winter in the Southern Hemisphere.) Whereas the North Pole is in a body of water surrounded by land, the South Pole is on a continent that is surrounded by water. Without the same hindrances, the ice is able to expand out from Antarctica into the ocean in all directions, forming a generally round shape. It is thinner on average and has greater freedom of movement.
The ice at both poles grows significantly during the winter and shrinks just as drastically in the summer due to seasonal temperature changes. The degree to which these changes occur depends mostly on how much hotter or colder the temperature is than normal. During the summer of 2012, sea ice in the Arctic shrunk to its smallest size in the history of record keeping. After building up again over the winter, the ice melted less in the summer of 2013, although it was still the sixth smallest “extent” of Arctic sea ice on record.
According to data from NASA, the average “extent” of September (summer) ice in the Arctic between 1979-2000 was 7 million square kilometers. However, the amount of ice has gradually drop since then, with some variations year-by-year. From a total of 6.2 million square kilometers in 1999, the September total eventually shrank to just 3.6 million in 2012. The 1979-2000 average for the March (winter) ice was 15.7 square kilometers. This level has not dropped nearly as much in more recent years, ranging from a low of 14.4 million kilometers in 2006 to a high of 15.6 million in 2001. The most recent total from March 2013 was 15 million square kilometers.
There were a lot of numbers in that last paragraph, but the basic point is that the amount of ice in the summer has declined significantly, while the amount of ice in the winter has experienced a more modest drop. What explains this difference? NASA’s theory is that while the winter cold is still forming a similar amount of ice, the greater temperature rises later in the year mean that there is less ice surviving year-round. Thus, although there has not been much of a change each winter, there is less overall ice cover throughout the year. I think that makes sense, but maybe others would disagree.
The story is different in Antarctica. NASA reports that since satellite imaging started being used to measure sea ice, there has been a rise of about 1% per decade in the amount of Antarctic ice. At nearly the same time that the Arctic Sea had its smallest amount of ice coverage (summer 2012), Antarctica was surrounded by the largest amount of ice coverage on record.
Once again, there are frequent variations in the amount of sea ice near the South Pole, but the general trend is a slight increase. However, it is worth pointing out that the Antarctic ice does not appear to be increasing as quickly as the Arctic ice is decreasing, and there also appear to be differences in the trend depending on which side of the Antarctic continent one is examining. But even if the level of growth is small, it has puzzled some scientists who expected that a global rise in sea temperatures would result in less ice everywhere.
A recent study by researchers at the University of Washington found that changes in wind currents could explain 80% of the increase in sea ice near Antarctica. I cannot say how reliable this information is: after all, it was funded by the National Science Foundation, the same people who successfully put shrimp on a treadmill. (Yet, without that NSF study, how would we have been able to gain videos like this one?)
Another study earlier this year by the Royal Netherlands Meteorological Institute (the Dutch are no doubt particularly interested in the possibility of rising sea levels) suggested that, somewhat paradoxically, runoff from melting ice shelves was actually keeping warmer water farther below the surface, thus allowing more ice to form. Hmm…
To sum up, it looks like there is a lot less ice in the Arctic, a little more in the Antarctic, and there is no consensus on why we are not seeing the same trend in both places. Still, the bottom line is that there is less sea ice overall in the world then there was a few decades ago. As for what is causing the Arctic to heat up, I will leave that for others to debate: I don’t get paid nearly enough to touch that question with a ten foot pole.
One final note: If you’ve ever wondered what would happen if all of the ice in the world were to melt, wonder no more. The National Geographic Society has answered that question for you in an interactive feature cleverly titled “If All the Ice Melted”. I’ll give you a hint: the East Coast goes, but the West Coast stays.
