Q: What is global warming?
A: Here's a simple definition of global warming. (And yes, it's really happening.) Over the past 50 years, the average global temperature has increased at the fastest rate in recorded history. And experts see the trend is accelerating: All but one of the 16 hottest years in NASA’s 134-year record have occurred since 2000.
Climate change deniers have argued that there has been a “pause” or a “slowdown” in rising global temperatures, but several recent studies, including a 2015 paper published in the journal Science, have disproved this claim. And scientists say that unless we curb global-warming emissions, average U.S. temperatures could increase by up to 10 degrees Fahrenheit over the next century.
Q: What causes global warming?
A: Global warming occurs when carbon dioxide (CO2) and other air pollutants and greenhouse gases collect in the atmosphere and absorb sunlight and solar radiation that have bounced off the earth’s surface. Normally, this radiation would escape into space—but these pollutants, which can last for years to centuries in the atmosphere, trap the heat and cause the planet to get hotter. That's what's known as the greenhouse effect.
In the United States, the burning of fossil fuels to make electricity is the largest source of heat-trapping pollution, producing about two billion tons of CO2 every year. Coal-burning power plants are by far the biggest polluters. The country’s second-largest source of carbon pollution is the transportation sector, which generates about 1.7 billion tons of CO2 emissions a year.
Curbing dangerous climate change requires very deep cuts in emissions, as well as the use of alternatives to fossil fuels worldwide. The good news is that we’ve started a turnaround: CO2 emissions in the United States actually decreased from 2005 to 2014, thanks in part to new, energy-efficient technology and the use of cleaner fuels. And scientists continue to develop new ways to modernize power plants, generate cleaner electricity, and burn less gasoline while we drive. The challenge is to be sure these solutions are put to use and widely adopted.
Q: How is global warming linked to extreme weather?
A: Scientists agree that the earth’s rising temperatures are fueling longer and hotter heat waves, more frequent droughts, heavier rainfall, and more powerful hurricanes. In 2015, for example, scientists said that an ongoing drought in California—the state’s worst water shortage in 1,200 years—had been intensified by 15 percent to 20 percent by global warming. They also said the odds of similar droughts happening in the future had roughly doubled over the past century. And in 2016, the National Academies of Science, Engineering, and Medicine announced that it’s now possible to confidently attribute certain weather events, like some heat waves, directly to climate change.
The earth’s ocean temperatures are getting warmer, too—which means that tropical storms can pick up more energy. So global warming could turn, say, a category 3 storm into a more dangerous category 4 storm. In fact, scientists have found that the frequency of North Atlantic hurricanes has increased since the early 1980s, as well as the number of storms that reach categories 4 and 5. In 2005, Hurricane Katrina—the costliest hurricane in U.S. history—struck New Orleans; the second-costliest, Hurricane Sandy, hit the East Coast in 2012.
The impacts of global warming are being felt across the globe. Extreme heat waves have caused tens of thousands of deaths around the world in recent years. And in an alarming sign of events to come, Antarctica has been losing about 134 billion metric tons of ice per year since 2002. This rate could speed up if we keep burning fossil fuels at our current pace, some experts say, causing sea levels to rise several meters over the next 50 to 150 years.
Q: What are the other effects of global warming?
A: Each year, scientists learn more about the consequences of global warming, and many agree that environmental, economic, and health consequences are likely to occur if current trends continue. Here’s just a smattering of what we can look forward to:
Melting glaciers, early snowmelt, and severe droughts will cause more dramatic water shortages and increase the risk of wildfires in the American West.
Rising sea levels will lead to coastal flooding on the Eastern Seaboard, especially in Florida, and in other areas such as the Gulf of Mexico.
Forests, farms, and cities will face troublesome new pests, heat waves, heavy downpours, and increased flooding. All those factors will damage or destroy agriculture and fisheries.
Disruption of habitats such as coral reefs and Alpine meadows could drive many plant and animal species to extinction.
Allergies, asthma, and infectious disease outbreaks will become more common due to increased growth of pollen-producing ragweed, higher levels of air pollution, and the spread of conditions favorable to pathogens and mosquitoes.
How You Can Stop Global Warming?
The goal is simple. Carbon dioxide is the climate’s worst enemy. It’s released when oil, coal, and other fossil fuels are burned for energy—the energy we use to power our homes, cars, and smartphones. By using less of it, we can curb our own contribution to climate change while also saving money. Here are a dozen easy, effective ways each one of us can make a difference:
1. Speak up!
What’s the single biggest way you can make an impact on global climate change? “Talk to your friends and family, and make sure your representatives are making good decisions,” Haq says. By voicing your concerns—via social media or, better yet, directly to your elected officials—you send a message that you care about the warming world. Encourage Congress to enact new laws that limit carbon emissions and require polluters to pay for the emissions they produce. “The main reason elected officials do anything difficult is because their constituents make them,” Haq says. You can help protect public lands, stop offshore drilling, and more here.
2. Power your home with renewable energy.
Choose a utility company that generates at least half its power from wind or solar and has been certified by Green-e Energy, an organization that vets renewable energy options. If that isn’t possible for you, take a look at your electric bill; many utilities now list other ways to support renewable sources on their monthly statements and websites.
3. Weatherize, weatherize, weatherize.
“Building heating and cooling are among the biggest uses of energy,” Haq says. Indeed, heating and air-conditioning account for almost half of home energy use. You can make your space more energy efficient by sealing drafts and ensuring it’s adequately insulated. You can also claim federal tax credits for many energy-efficiency home improvements.
4. Invest in energy-efficient appliances.
Since they were first implemented nationally in 1987, efficiency standards for dozens of appliances and products have kept 2.3 billion tons of carbon dioxide out of the air. That’s about the same amount as the annual carbon pollution coughed up by nearly 440 million cars. “Energy efficiency is the lowest-cost way to reduce emissions,” Haq says. When shopping for refrigerators, washing machines, and other appliances, look for the Energy Star label. It will tell you which are the most efficient.
5. Reduce water waste.
Saving water reduces carbon pollution, too. That's because it takes a lot of energy to pump, heat, and treat your water. So take shorter showers, turn off the tap while brushing your teeth, and switch to WaterSense-labeled fixtures and appliances. The EPA estimates that if just one out of every 100 American homes were retrofitted with water-efficient fixtures, about 100 million kilowatt-hours of electricity per year would be saved—avoiding 80,000 tons of global warming pollution.
6. Actually eat the food you buy—and make less of it meat.
Approximately 10 percent of U.S. energy use goes into growing, processing, packaging, and shipping food—about 40 percent of which just winds up in the landfill. “If you’re wasting less food, you’re likely cutting down on energy consumption,” Haq says. And since livestock products are among the most resource-intensive to produce, eating meat-free meals can make a big difference, too.
7. Buy better bulbs.
LED lightbulbs use up to 80 percent less energy than conventional incandescents. They’re also cheaper in the long run: A 10-watt LED that replaces your traditional 60-watt bulb will save you $125 over the lightbulb’s life.
8. Pull the plug(s).
Taken together, the outlets in your home are likely powering about 65 different devices—an average load for a home in the U.S. Audio and video devices, cordless vacuums and power tools, and other electronics use energy even when they're not charging. This "idle load" across all U.S. households adds up to the output of 50 large power plants in the U.S. So don't leave fully charged devices plugged into your home's outlets, unplug rarely used devices or plug them into power strips and timers, and adjust your computers and monitors to automatically power down to the lowest power mode when not in use.
9. Drive a fuel-efficient vehicle.
Gas-smart cars, such as hybrids and fully electric vehicles, save fuel and money. And once all cars and light trucks meet 2025’s clean car standards, which means averaging 54.5 miles per gallon, they’ll be a mainstay. For good reason: Relative to a national fleet of vehicles that averaged only 28.3 miles per gallon in 2011, Americans will spend $80 billion less at the pump each year and cut their automotive emissions by half. Before you buy a new set of wheels, compare fuel-economy performance here.
10. Maintain your ride.
If all Americans kept their tires properly inflated, we could save 1.2 billion gallons of gas each year. A simple tune-up can boost miles per gallon anywhere from 4 percent to 40 percent, and a new air filter can get you a 10 percent boost.
11. Rethink planes, trains, and automobiles.
Choosing to live in walkable smart-growth cities and towns with quality public transportation leads to less driving, less money spent on fuel, and less pollution in the air. Less frequent flying can make a big difference, too. “Air transport is a major source of climate pollution,” Haq says. “If you can take a train instead, do that.”
12. Shrink your carbon profile.
You can offset the carbon you produce by purchasing carbon offsets, which represent clean power that you can add to the nation’s energy grid in place of power from fossil fuels. But not all carbon offset companies are alike. Do your homework to find the best supplier.
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