Let me address the second line you provided first. The claim of that article is that there have been warm cycles in the past. Therefore, the conclusion is that this is just a natural cycle. I have addressed this issue many times and you can read a posting I wrote on just this topic. But, basically, the idea that past natural cycles proves our current warming trend is just a natural cycle is a false argument. No evidence is given to indicate we are in a naturally occurring warm cycle and no effort is made to refute the science that shows we are actually in a naturally occurring cool cycle, not a warm one. So, we cannot blame nature for what is going on.
I have also addressed the issue of sea ice around Antarctica and the Arctic region in previous posts, but will talk about them some more.
Saying the sea ice is increasing/decreasing is not, by itself, proof regarding AGW, one way or the other. When we say 'global warming' we mean the whole globe and you cannot take an isolated area as 'proof.' You can use it as evidence, but it must be placed in the total picture for it to have value. This is true as evidence supporting AGW as it is as evidence against AGW.
So, where does this issue of sea ice stand in the total 'global' picture? Sea ice around Antarctica is increasing while sea ice in the Arctic region is decreasing. Well, there is a huge difference between the two - the continent of Antarctica. Let's look at the total ice balance for Antarctica to see what is happening. This is a graph of the monthly change in the mass balance for Antarctica as measured by the GRACE satellite program. It was provided in a report on a joint NASA/ESA study that found the ice sheet at both ends of the planet are getting smaller. Units are in gigatons of ice.
It is easy to see that Antarctica has a downward trend in the amount of ice in the ice sheet. So, the sea ice is increasing, but the land ice is decreasing.
What about up north? Well, there is no continent in the Arctic Ocean, it is all open water, but there is the second largest ice sheet in the world nearby on Greenland. What is happening there? Here is the GRACE data for the Greenland ice sheet:
|Source: Polar Portal|
One again, we see the total mass of the ice sheet is decreasing over time.
So, we have the Antarctic sea ice increasing, but Antarctic land ice, Greenland ice sheet, and Arctic sea ice all decreasing.
Now, we have a more complete picture of the ice situation at the poles (we did not mention how land ice all over the world is decreasing). In this larger context we can see that there is some anomaly regarding the Antarctic sea ice that bears investigation, but the over all evidence is that the total ice is decreasing at a rather alarming rate.
This is what we would expect to see with global warming.
You did not prove man made global warming is not real.