Scientists have said that events such as deforestation, the use of automobiles, burning of fossil fuels, etc. will intensify the greenhouse effect. The greenhouse effect occurs within the Earth's atmosphere and acts a "heat blanket". Over time, it slowly warms up the surface of the Earth causing global warming.
There are people who believe that global warming is a threat. Those who think it is a threat will argue that global warming is placing the planet in danger. Ice caps are melting, droughts and heat waves will occur, economic issues will surface, there will more hurricanes, and there will be an increase in disease.
There are also people who believe that global warming is a natural occurring event and will happen regardless of what we do.