What is a greenhouse gas? Greenhouse gases are aptly named, as they’re gases that trap heat in the atmosphere, acting as a blanket to trap the energy from sunlight as it’s reflected off the earth. Among the most common greenhouse gases are carbon dioxide, methane, nitrous oxide, and fluorinated gases1. Some greenhouse gases, like methane, water vapor and carbon dioxide, occur naturally, while others are manmade.
Where do greenhouse gases come from? Unfortunately, greenhouse gases mainly come from the actions of humans (the world’s food system alone accounts for one-third of human-caused greenhouse gas emissions2). Carbon dioxide comes from the burning of fossil fuels like coal and natural gas, methane is emitted from livestock and decomposing organic waste, such as food in landfills, and other gases come from manufacturing and other industrial processes. One of the most notorious greenhouse gases is called “tropospheric ozone”3, which is caused by industrial pollution and automobile exhaust (and not to be confused with stratospheric ozone, which is a natural protective layer above the earth that reduces UV radiation).
Why are greenhouse gases bad? While a certain protective layer around our atmosphere is essential, the problem arises when the greenhouse gases are so concentrated that they trap too much heat and upset the equilibrium that keeps our climate moderate. Greenhouse gases warm the atmosphere so much (you’ve heard of global warming — this is it!), that they trigger other major environmental changes like droughts, rising sea levels, floods and other environmental issues. The EPA shows the connection between greenhouse gases and environmental changes like this:
How are they measured? Greenhouses gases are measured by instruments around the world, and overseen by governments and third-party organizations like Earth Networks. These instruments can measure concentrations of CO2, methane and other gases, can monitor changes, and can even trace some of the gases back to their original sources. The Environmental Protection Agency collects and publishes detailed data on greenhouse gas emissions every year in their Inventory of U.S. Greenhouse Gas Emissions and Sinks (Inventory) report.
What can we do to reduce greenhouse gas? Reducing greenhouse gas emissions is not out of reach! The small things we each do to change our lifestyles can have a huge collective impact on the environment. Here are a few tips to try out, to minimize the greenhouse gas emissions that you’re responsible for:
When you’re driving, do your best to use less gas.
- Increase fuel economy by driving slower, braking less, and using cruise control.
- Drive a fuel-efficient car and keep it properly maintained.
- If at all possible, walk, ride a bike, or take public transportation.
When you’re at home, try to reduce your energy use.
- Reduce the amount of electricity you use by unplugging appliances when not in use (even when they’re plugged in, they still pull energy), turning off lights when you leave the room, and turning on the energy-saving features on your computer, like sleep mode.
- Keep your thermostat lower in the Winter and higher in the Summer (your HVAC system won’t have to use as much energy then). Keep filters clean and program your thermostat so that you’re not heating or cooling the house when no one’s home.
- Save water by washing dishes in filled sinks rather than under a constantly running faucet, taking shorter showers, and installing water-saving devices in your toilets. Using less water means you’ll use less energy to pump and heat the water.
- Recycle! It takes less energy to make products from recycled materials, than it does to make products from new materials, so recycle and buy recycled when possible.
When you’re eating, think about where your food comes from — and where it will go.
- Eat local. Food that comes from other countries or even from the U.S. has to be transported in refrigerated ships or trucks, which use a lot of gas.
- Shop for organic foods. The pesticides and fertilizers used to grow most commercial food crops contribute to synthetic greenhouse gases, but organic foods are grown without pesticides and fertilizers.
- Waste nothing. Decomposing food accounts for serious methane gas emissions in landfills5, so be sure to throw away as little food as possible. Buy only what you can eat, make use of your leftovers, and maybe even consider composting food scraps instead of throwing them in the trash.
You might also consider buying carbon offsets to further reduce your impact. Buying a carbon offset is basically investing in a project that helps to reduce or eliminate an amount of greenhouse gas emissions similar to what you might be generating. Search “buy carbon offsets” to find a company you’re comfortable supporting.
1 National Oceanic And Atmospheric Administration (NOAA)
2 Nature: International Weekly Journal of Science
3 GreenHouse Gas Online (GHG Online)