Right after my previous article that discussed the historical problems in Antarctica, I found another article about Antarctica in National Geographic that uses modelling to answer the “mystery” of the Antarctic sea ice increase over the past 30 years. The reason it is a mystery is because that increase in sea ice coverage is contrary to the theory of global warming.
This paper got plenty of attention when it was released last August and many, many problems have been pointed out by others, but most of the discussion has focused on the inappropriate definition of warming that has taken place in the Southern Ocean. The main problem that was brought up last summer was there is very little accurate data prior to 1978 (pre satellite data problem once again, as usual). The paper is specific in its discussion of warming from 1950-1999. The main prior discussion was about the lack of valid data for the pre-1978 period. It is easy to make a warming trend when half the period has no useful data.
What didn’t get discussed was the actual behavior of temperature and Antarctic sea ice. From 1979-present there is plenty of satellite data that provides good coverage of the area. Since that also coincides with the period that has accurate coverage of the sea ice, it’s worth taking a look at the behavior of the period in question.
This is important because once again the results of the paper depend on GCM results. This paper is a great example of ignoring the obvious answers in favor of model results. The biggest problem I have is trying to figure out how to organize the argument clearly enough to properly tear it apart… So I will start by building on the parts that are correct.
The article even manages to start off on the right foot with this accurate summary of what has been happening to the sea ice in both polar regions.
“Satellite data show that, over the past 30 years, Arctic sea ice has declined while Antarctic sea ice has mysteriously expanded”
So far so good, that part is correct. It also makes another profoundly correct statement that “the two polar ecosystems are so different” from each other. I fully agree that they are different. As I pointed out in my last article about Antarctica.
Here are the charts for the two regions in question.
Since the warmists argue that the decreasing Arctic trend is caused by global warming, the theory should also cause the Antarctic sea ice to behave in the same manner. That is not happening. This is why the whole thing is a mystery. Antarctica is not behaving like their theory predicts, so GCM’s once again to the rescue.
The Antarctic Circumpolar Current (ACC) dominates the climate of the ocean and of Antarctica. This can be easily be seen in animations of the Antarctic sea ice. While I agree with the point that the ACC (which isn’t mentioned in the paper) is dominant, the article makes the following suspiciously unsupported and odd statement.
“Antarctic ice forms and melts each year and has always been governed more by wind and ocean circulation than air temperatures”
Based on that statement it would seem that wind and ocean cause the ice to form and not the actual temperature of the air. So does that mean warm air would cause the ocean to freeze? They make the argument that warming has been happening, but that is based on a lack of data prior to 1978, but then they ignore the modern satellite data of the region, but the satellite data of the region shows a slight cooling trend.
The fact is that the RSS satellite data covers 60S to 70S latitude. This is a very interesting region because it covers a majority of where the sea ice forms. The RSS data for the past 30 years shows a small cooling trend of -0.02 °C/decade for the region where the sea ice forms. Perhaps that is why they argue that air temperature doesn’t matter for the sea ice, because then the cause of the increasing ice would be decreasing temperature, but decreasing temperatures is also counter to the theory of global warming.
The UAH covers from 60S to 85S. This covers the same region as the RSS and also much more into the Antarctic continent. The coverage that includes much more of the continent itself shows an even stronger cooling trend of -0.07 °C/decade. It would make sense that the ocean would change temperature at a slower rate than the land would. So the ocean is weakly cooling and the Antarctic continent is strongly cooling.
So the real purpose of the paper is to build a model that shows warming temperatures that results in increased sea ice. They do this by saying that precipitation is causing the salinity of the Southern Ocean to drop which is why the sea ice is increasing. So less salty water is the reason that the sea ice is expanding.
So the paper builds a model that shows how warming can cause the sea ice to increase. That is some really impressive modelling. I am sure that it is… something.
But wait, even the warmists are shredding this paper. Trenberth himself has waded in saying that the model is missing the ozone hole. So Trenberth himself says the model is missing key components, but still the paper survived peer review and gets published….. Then gets touted as proof that global warming is legit. Not that the ozone hole matters, but that is another article.
So here is a paper that pretty much everyone agrees is full of holes (almost no pun intended), but it is still got real news coverage. This is a paper that just has a big fat target on it. This is so bad that it almost makes me think that they are trying to poke fun at global warming.
With that in mind, I saved the best for last. This is supposed to be the main scientific takeaway from the paper.
“Climate scientists have cracked the mystery of why Antarctic sea ice has managed to grow despite global warming—but the results suggest the trend may rapidly reverse, a new study says.”
“cannot give you a precise year—but definitely in this century”
So the trend in growing sea ice might definitely reverse in this century based on a model that shows warming air causes more sea ice.
Take that skeptics.