Why is global warming happening? I don't know anything about it.
I'll tell you why...
Shrinking Ice Sheets
These following slides are some of the reasons why Global Warming is happening....
The oceans have absorbed much of this increased heat, with the top 700 meters (about 2,300 feet) of ocean showing warming of more than 0.4 degrees Fahrenheit since 1969.
Extreme Weather Events
The Greenland and Antarctic ice sheets have decreased in mass. Data from NASA's Climate Experiment show Greenland lost an average of 286 billion tons of ice per year between 1993 and 2016, while Antarctica lost about 127 billion tons of ice per year during the same time period. The rate of Antarctica ice mass loss has tripled in the last decade.
Glaciers are retreating almost everywhere around the world; including in the Alps, Himalayas, Andes, Rockies, Alaska and Africa
The number of record high temperature events in the United States has been increasing, while the number of record low temperature events has been decreasing, since 1950. The U.S. has also witnessed increasing numbers of intense rainfall events.
Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has increased by about 30 percent.13,14 This increase is the result of humans emitting more carbon dioxide into the atmosphere and hence more being absorbed into the oceans. The amount of carbon dioxide absorbed by the upper layer of the oceans is increasing by about 2 billion tons per year.