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Am Fam Physician. 2011;84(3):282-283

See related article on global warming.

What is global warming?

Global warming is when the Earth's average surface temperature goes up over time. Because of this, the Earth is getting warmer with each decade. Scientists have found that this is mostly caused by human activities that affect air pollution.

When people burn fossil fuels for energy (example: driving vehicles that use gasoline), it puts gases into the air. Sometimes these gases are called greenhouse gases because having too much of them in the air causes what is called the greenhouse effect.

A greenhouse is a building where plants are grown. It usually has a glass ceiling and walls for the sun to shine through. The sun's heat goes in through the glass more easily than it can get back out of it. This causes the temperature inside the greenhouse to get warmer than it is outside. Greenhouse gases cause global warming by acting like the glass of a greenhouse around the Earth's atmosphere. Adding to the problem, people also have removed a lot of the Earth's plants that would help absorb the greenhouse gas carbon dioxide.

How will it affect my health?

Warmer average temperatures can increase the risk of health problems. Global warming will cause direct and indirect effects on health. The direct effects would be easier to see and may show up first (Table 1), but the indirect effects would be the most serious (Table 2).

Change caused by global warmingHow this change affects healthWho is the most at risk?
Heat waves come more often, are more severe, and last longerHeat stress makes people sickEveryone, but especially older people and children
Heat stroke can be deadly
Average temperatures are warmer, summers last longerIncrease in infectious diseases, especially those carried by insectsEveryone, but especially people who live in countries that don't have good public health care systems
Air pollution gets worseMore risk of heart and lung diseases, such as asthma and heart attacksEveryone, but especially people who already have heart or lung disease
More severe storms cause flooding and damage from wind, snow, and hailMore accidents and injuriesEveryone
Change caused by global warmingHow this change affects healthWho is the most at risk?
Sea levels risePeople, property, and jobs are displaced, causing economic challengesEveryone, but especially those living in coastal communities
Changes in temperature and precipitation that affect cropsLess food supplies, causing price increases and shortagesEveryone, but especially the poor
Changes in temperature and precipitation that cause more frequent and serious droughtsThreatened water supplies and water qualityEveryone, especially those living in areas that are already dry
Earth's natural systems that supply clean air, clean water, and food become more stressed and may shut down in some areasAdditional risks to food and water, causing millions of people to change location, threatening global securityEveryone

What can I do to help?

About one-fifth of all greenhouse gases come from the production of food animals. Raising cows generates the most greenhouse gases. Your doctor may have talked about the health benefits of a low cholesterol diet, but reducing global warming is another good reason to eat less meat. Most Americans eat about 12 ounces of meat per day. Try to only eat about 3 ounces of meat per day (about the size of a hamburger patty). Also make sure that less than one-half of that amount is from beef.

Another way to help is using your car less. Short car trips cause more air pollution per mile than longer trips. Instead of always driving to nearby places, try walking or biking. For information about how to ride a bicycle safely, especially in the city, go to http://www.nhtsa.gov/Bicycles. Start by doing this in place of one short car trip per week. Work up to replacing most of your short car trips this way. This will help create less air pollution, making the air in your community cleaner. Also, the extra exercise could help make you healthier.

Where can I get more information?

Environmental Protection Agency

Meatless Monday Campaign

National Highway Traffic Safety Administration

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