Debate , how is global warming real? How is global warming real? what proof do we have?

NASA provides a nice explanation of how they calculate the average global temperature here:

http://www.giss.nasa.gov/research/featur...

If you want to know whether humans are causing this warming, the answer is yet, but it would be a much longer explanation how we know that. 7% 1 Vote
2 http://www.nasa.gov/centers/goddard/mpg/... 0% 0 Votes

Global Warming is real the world temperature is going up 1.8 degrees per 1 year.In about 2050 the sea level is going to rise upto 20-30 ft.That is because of global warming. Google 0% 0 Votes