What's happening? Firstly the sun is increasing temperatures world wide (Never mind why for now.). This is average temperature. While some places may be cooler others are warmer but, according to the scientific community, the net average temperature is higher. The tabulation of this information is itself a mammoth task. This increase in temperature increases ocean temperatures too, which leads us to another effect. When ocean temperature rises and the world in general is warmer the amount of moisture drawn from the oceans by the sun increases. This increases the cloud cover causing more of the sun to be reflected back into space which should, at least temporarily, have a cooling effect. Trouble comes in the form of storms. With all the extra water in the clouds the rains are much heavier and the storms much more volatile. Once the clouds have dumped their water they no longer block the sun and the heating can start again. The volatility increases. So where does this balance come? How can the scientific community predict the exact level of warming when there are so many variables?
Other factors, earthquakes, floods, fires, desertification, melting ice caps and glaciers, all add to the mix. I'm ignoring earthquakes here because they have a page all their own. Floods like the recent flooding in Pakistan add to the water surface and promote increased water draw. Fires increase the CO2 and pollutants in the air to block the sun while increasing the heat trapping characteristics of the atmosphere. Desertification reduces the water uptake but increases the fires. Melting ice breaking off into the oceans reduces the temperature of the ocean but reflects less heat from the sun which increases the temperature of the oceans thus increasing the water drawn which increases the cloud cover thus increasing the frequency and volatility of storms which....whoa. Catch my drift? The problem is monstrous and so far the scientists, to their credit, are doing a darn good job of sorting it out. Of course there are still those who think the earth is flat, and there always will be.
And by the way, 1 + 1 does equal 10. If you doubt me, check it out with your favorite math person. Hint. This is based on the most heavily used math system world wide.