Comments such as "global warming is adding four million Hiroshima bombs to the globe everyday" are so absurd they should deserve no comment.  But it's apparently necessary.  Contemplate how much total heat the atmosphere possesses; enough to rise it from -273C (absolute zero if there were no sun) to ~15C average today. That's 288 total degrees for the entire atmosphere, or (I'm neglecting phase changes, which add more energy to the equation).  Now, the addition of (0.8C/century)/(century/100 years)(year/365 days) = 2.192e-5C/day of the total atmospheric energy added to the planet every day.  If that's 4 million atomic bombs, then those four million (Hiroshima sized) bombs increases the atmosphere's energy only by 0.002192% each day.  Of course if a day is unusually hot, say 10C hotter, then that is (10.00/2.192e-5C) X 4 million bombs = 1.8 trillion Hiroshima bombs to produce that extra heat (far, far, far larger than the entire Earth's nuclear arsenals).  And that is nothing compared the heat of the whole atmosphere.

It's just a scare mechanism.  And putting it terms of nuclear weapons (which it has nothing to do with) just nails in the terror.  And worse, if anything, it has the opposite effect.  Global warming and climate change should be talked about -- to the public -- soberly, responsibly, and with as much scientific explanation as the public can handle.  The doubts and problems should be admitted.  PR campaigns, falsehoods, one-sided presentations, exaggerations, and ads like the above will only be seen as they are, leading to further resistance.