It may be true that the Polar ice cap has not become less in 2013, in fact increased by 50% compared to the lowest in 2012, but this is still low compared to its highest level.
Global warming trend does not mean that it will keep on getting warmer year by year. There will surely be fluctuations in temperature. What is important is the trend.
The temperature trend appear to be very little change in global temperature for the past 17 years and yet the Ice cap keeps on getting less and less year by year, until 2013, when it suddenly increase by 50%.
It could be due to efforts in conserving the environments by using Electric and hybrid cars in the USA and Canada. In China, it is a different story and yet, even in China, environmental awareness has increased.
These climate change denials are just nonsense. They don't seem to understand anything about statistics. They pick on exceptions instead of the general trends. They even ignore all the efforts to reduce global warming so far and the very clear and obvious eveidences of global warming such as the continual reduction in the polar ice caps for the past decade, and yet dismiss all those years, just because in 2013, the polar ice cap has increased in size.
That is good news, but it still has a long way to go back to the original levels of ice caps.