It's raining but my fan is on, why? It's raining but I had to take off my cloth, why? There was a time when at the slightest rainfall we jump in our sweaters for comfort. There was a time when on a sunny afternoon that fan was blowing too fast, now it's not enough. Why? What is the cause?

Global Warming

What is global warming?

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.

What causes global warming?

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.

Key Facts about Global Warming

• Global warming is the increase of Earth's average surface temperature due to greenhouse gases that collect in the atmosphere like a thickening blanket, trapping the sun's heat and causing the planet to warm up.

• Greenhouse gases keep heat close to the earth’s surface making it livable for humans and animals. However, global warming is happening largely due to an over-emittance of these gases and fossil fuels (natural oil, gasoline, coal).

• With the start of industry in the 1700's, humans began emitting more fossil fuels from coal, oil, and gas to run our cars, trucks, and factories. By driving a “smarter” car, you will not only save on gas, but help prevent global warming.

• There is more carbon dioxide in the atmosphere today than at any point in the last 800,000 years.

• Though Americans make up just 4 percent of the world's population, we produce 25 percent of the carbon dioxide pollution from fossil-fuel burning by far the largest share of any country.

• The Environmental Protection Agency (EPA) has both the authority and responsibility to reduce pollution from electric power plants under the Clean Air Act, the nation's bedrock air pollution law adopted in 1970.

• Since 1870, global sea levels have risen by about 8 inches.

• Global climate change has already had observable effects on the environment. Glaciers have shrunk, ice on rivers and lakes is breaking up earlier, plant and animal ranges have shifted and trees are flowering sooner.

• Heat waves caused by global warming present greater risk of heat-related illness and death, most frequently among people who have diabetes who are elderly or are very young.

• According to the U.S. Global Change Research Program, the temperature in the U.S. has increased by 2 degrees in the last 50 years and precipitation has increased by 5%.

• Global warming puts coral reefs in danger as the ocean warms, scientist fear that coral reefs will not be able to adapt quickly enough to the resulting changing conditions, and bleaching incidents and diseases will increase.

What are the other effects of global warming?

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.