Additional info

From: http://science.nasa.gov/earth-science/big-questions/how-does-the-earth-system-respond-to-natural-and-human-induced-changes/

“Earth's climate system is "sensitive" to any of the aforementioned changes at a scale of 1 watt per square meter, or greater. That amount of energy equals one Christmas tree light bulb for every 3-foot by 3-foot square of our world's surface. Climate scientists found that adding to or reducing Earth's energy budget by 1 watt per square meter is enough to cause the globe to warm or cool, depending upon the direction and magnitude of the change. “

From: http://www.universetoday.com/25756/surface-area-of-the-earth/

“The total surface area of the Earth is 510 million square kilometers.“

Or 510,000,000,0000,0000 square meters. So, if these numbers are correct, then all that is needed is 510,000,000 megawatts of power to increase the temperature of the Earth‘s climate.
The quicker that amount of energy is generated and released into the environment, the quicker the globe will heat up.
493,014 quadrillion BTU of energy was used in the year 2008.
Info from: http://www.eia.gov/cfapps/ipdbproject/IEDIndex3.cfm?tid=44&pid=44&aid=2

Converting 493,014 quadrillion BTU to 5.202*10^23 Joules, so in 2008 there was 1.445*10^20 W h. of power being used.
To me, that seems like enough power, or energy, usage to increase the globe’s temperature.
Somebody check the math.