Actually, even back in the 1970s there were more scientists who were inclined to believe in global warming than in global cooling. It is just that cooling was more interesting to put in the news...
For instance, Global warming was one of the more important topics of the Stockholm Conference in 1972 (the biggest conference on the environment in the 70's) , while global cooling wasn't even hinted at.
Of course not all of the world is warming right now.
Some parts of the world are indeed cooling (temporarily) because of warming having disrupting ocean currents that would otherwise warm those areas, or from warming having caused some areas to be cloudier and/or rainier.
That is why climatologists prefer to use the term "Climate Change" rather than "Global Warming".
Beside the effects of carbon compounds in the atmosphere, there is also the effect of increased aerosols from human activity and those do cause a bit of climate change in form of more clouds, which cool. It has been theorized that this had contributed significantly to the Ethiopian famine in the mid-1980s - again, the effect in one part of the system causing a different effect in another. Ethiopia got a draught while another part of Africa got more rain.
But while carbon emissions take thirty or more years to make a measurable difference in the atmosphere, aerosol cooling is very temporary. The white condensation trails from airplanes do contribute to cooling (cue the tin foil hat people :-P ) and that is only because how they are artificial clouds - and clouds cool. Back in September 11, 2001, airplanes across the USA were grounded causing the airspace above USA to be clear from condensation trails for the first time in decades - which had a measurable effect on the weather that day. But it was back to "normal" a couple of days later.