Disappearing Sea Ice? Global warming?

A few weeks ago, my cousin told me there was a webpage about climate change fraud, but I didn't pay attention to it until last week when I remembered I had to do my blog posts. So I googled the site and found lots and lots of forums, blogs, etc. I can't believe that maybe this global issue is a hoax!

One of the things I read was about the disappearing sea ice caused by global warming. It says that this is not a manmade effect, this is a natural effect. This has been happening for thousands of years and we assume that CO2 emissions, which started less than 200 years ago, are the cause of global warming. It is true that since 1800's, earth has been warmer but for natural causes, not by CO2. Earth's temperature is constantly changing. Even around the year 1000's, Central Greenlind's Ice Core was much warmer that what we are experiencing now. When agriculture started, the climate in there was even warmer than in the year 1000's. Around 13000 years ago, there was the last ice age and temperature had being rising until -8000 B.C. and maintaned "stable" (30°C - 35°C) until now. There was no CO2 emissions by burning fossil fuels in that time. Now at days in Central Greenland Ice Core, the temperature is colder that how it was around -1300 B.C.

Now, going to the Antartica, as you can see in the chart, there have been several periods where the is it cooler and then comes a big change on temperature warming the Earth. And in this chart you can also see there is a relation between what happened in Central Greenland Ice Core, there was an ice age before -11000 B.C. and now seems to be stable.
So now, you can see that there is no influence of CO2, with the melting ice cores. What is happening is a natural effect made by the amazing Mother Nature. Politicians and scientists convince us by putting a photograph of a polar bear cub, which touches our heart and make a global warming poster.