The ozone hole causes global warming
The ozone hole is caused by chlorofluorocarbons breaking down stratospheric ozone over Antarctica. Global warming is driven by greenhouse gases trapping infrared radiation at lower altitudes. The energy addition from the ozone hole is far too small to explain observed warming.
What we know
The ozone hole and climate change are distinct environmental problems that share only the fact that both result from human industrial activity. The ozone hole is the depletion of stratospheric ozone (mostly over Antarctica) caused by chlorofluorocarbons (CFCs) and related chemicals. Global warming is the accumulation of heat energy in the lower atmosphere and oceans driven by CO2, methane, and other greenhouse gases.
NASA's analysis explains why the ozone hole cannot drive global warming: UV light makes up only about 8 percent of total incoming sunlight, and ozone plus atmospheric oxygen already block most of it. The additional UV reaching the surface due to the Antarctic ozone hole is a small fraction of an already small fraction, an amount far too minor to account for the observed global temperature rise. Furthermore, the primary local effect of stratospheric ozone depletion is cooling of the Antarctic stratosphere, not warming.
There is a subtle connection in the other direction: greenhouse-gas-induced warming of the lower atmosphere cools the stratosphere, which can enhance polar ozone depletion. The two phenomena interact, but this is different from the ozone hole causing warming. Both problems need to be addressed independently. The Montreal Protocol has successfully reduced CFC emissions and the ozone layer is slowly recovering, while greenhouse gas emissions continue to drive warming through a completely separate mechanism.
Common claims
- The ozone hole lets in more heat from the sun, causing warmingFalse - UV increase is too small; warming is from IR trapping by greenhouse gases
- The ozone hole and global warming are the same problemFalse - different causes, different mechanisms, different locations
- Fixing the ozone hole will stop climate changeFalse - requires separate reductions in CO2 and other greenhouse gases