National Geographic and Global Warming

Looking through some of the websites advised by our teacher, I found out that there are lots of information showing that global warming does exist.
From National Geographic:
"Now, humans have increased the amount of carbon dioxide in the atmosphere by more than a third since the industrial revolution. Changes this large have historically taken thousands of years, but are now happening over the course of decades"
Carbon dioxide is a greenhouse gas which means that in the atmosphere, it can trap the heat of the sun instead of having the rays bounce off the earth and go through our atmosphere. Having more carbon dioxide increases the amount of greenhouse gasses in the atmosphere which will warm up our planet. This is not a theory, it is a present issue happening now. As the quote above states, our planet is heating up over a period of decades which should be happening over the course of a few thousand years. National Geographic points out that Glacier national park now has 27 glaciers when in 1910, there were 150 glaciers. This change happened in just a few centuries when it should have happened over thousands of years. These changes happening in our world are happening too quickly. National Geographic also states that the IPCC notices that the temperature of earth is rising, nearly 11 out of the last 12 years are the hottest on record. The government of the USA also recognizes global warming because Bush stated that anthropogenic carbon dioxide is responsible for global warming. Anthropogenic means that humans are responsible for global warming.