Poor air quality
Death by smog will become increasingly common on an overheated planet — warmer temperatures help intensify smog levels. In fact, doctors have said that smog-related deaths could rise by 80 percent over the next 20 years.
Additionally, climate change increases ground-level ozone when nitrogen oxides and volatile organic compounds react with sunlight, which is especially damaging to lung tissue. Plus, a 2004 Harvard study showed that higher concentrations of carbon dioxide in the atmosphere help allergens like mold and ragweed grow, which means more allergies and higher rates of asthma attacks. Mix in some volcanic ash and smoke from wildfires and you have a good recipe for worldwide respiratory problems.