GREENHOUSE EFFECT

what is greenhouse effect?

The greenhouse effect is a process that occurs when gases in Earth's atmosphere trap the Sun's heat. This process makes Earth much warmer than it would be without an atmosphere. The greenhouse effect is one of the things that makes Earth a comfortable place to live.

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How does the greenhouse effect work?  

As you might expect from the name, the greenhouse effect works  like a greenhouse! A greenhouse is a building with glass walls and a glass roof. Greenhouses are used to grow plants, such as tomatoes and tropical flowers.

A greenhouse stays warm inside, even during the winter. In the daytime, sunlight shines into the greenhouse and warms the plants and air inside. At nighttime, it's colder outside, but the greenhouse stays pretty warm inside. That's because the glass walls of the greenhouse trap the Sun's heat.

The greenhouse effect works much the same way on Earth. Gases in the atmosphere, such as carbon dioxide, trap heat just like the glass roof of a greenhouse. These heat-trapping gases are called greenhouse gases.

During the day, the Sun shines through the atmosphere. Earth's surface warms up in the sunlight. At night, Earth's surface cools, releasing heat back into the air. But some of the heat is trapped by the greenhouse gases in the atmosphere. That's what keeps our Earth a warm and cozy 58 degrees Fahrenheit (14 degrees Celsius), on average.

greenhouse gases-Greenhouse gases are gases that can trap heat. They get their name from greenhouses. A greenhouse is full of windows that let in sunlight. That sunlight creates warmth. The big trick of a greenhouse is that it doesn’t let that warmth escape.

That’s exactly how greenhouse gases act. They let sunlight pass through the atmosphere, but they prevent the heat that the sunlight brings from leaving the atmosphere. Overall, greenhouse gases are a good thing. Without them, our planet would be too cold, and life as we know it would not exist. But there can be too much of a good thing. Scientists are worried that human activities are adding too much of these gases to the atmosphere.

 The main greenhouse gases are:

• Water vapor
• Carbon dioxide
• Methane                    
• Ozone
• Nitrous oxide
• Chlorofluorocarbons

How greenhouse gases affect global warming

The gases in the atmosphere that absorb radiation are known as "greenhouse gases" (sometimes abbreviated as GHG) because they are largely responsible for the greenhouse effect. The greenhouse effect, in turn, is one of the leading causes of global warming. The most significant greenhouse gases are water vapor (H2O), carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), according to the ENVIRONMENT PROTECTION AGENCY (EPA). "While oxygen (O2) is the second most abundant gas in our atmosphere, O2 does not absorb thermal infrared radiation," said Michael Daley, an associate professor of environmental science at Lasell College in Massachusetts.

While some argue that global warming is a natural process and that there have always been greenhouse gases, the amount of gases in the atmosphere has skyrocketed in recent history. Before the Industrial Revolution, atmospheric CO2 fluctuated between about 180 parts per million (ppm) during ice ages and 280 ppm during interglacial warm periods. Since the Industrial Revolution, though, the amount of CO2 has increased 100 times faster than the increase when the last ice age ended, according to the NATIONAL OCEANIC AND ATMOSPHERE ADMINISTRATION (NOAA).

Fluorinated gases — that is, gases to which the element fluorine was added — including hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride, are created during industrial processes and are also considered greenhouse gases. Though they are present in very small concentrations, they trap heat very effectively, making them high "global-warming potential" (GWP) gases.

Chlorofluorocarbons (CFCs), once used as refrigerants and aerosol propellants until they were phased out by international agreement, are also greenhouse gases.

There are three factors affect the degree to which any greenhouse gas will influence global warming, as follows:    

• Its abundance in the atmosphere.
• How long it stays in the atmosphere.
• Its global-warming potential.

Carbon dioxide has a significant impact on global warming partly because of its abundance in the atmosphere. According to the EPA in 2016, U.S. greenhouse gas emissions totaled 6,511 million metric tons (7,177 million tons) of carbon dioxide equivalents, which equaled 81 percent of all human-caused greenhouse gases — down 2.5 percent from the year before. Additionally, CO2 stays in the atmosphere for thousands of years.

However, methane is about 21 times more efficient at absorbing radiation than CO2, giving it a higher GWP rating, even though it stays in the atmosphere only about 10 years, according to the EPA.

Our planet's future

If current trends continue, scientists, government officials and a growing number of citizens fear that the worst effects of global warming — extreme weather, rising sea levels, plant and animal extinctions, ocean acidification, major shifts in climate and unprecedented social upheaval — will be inevitable.

In answer to the problems caused by global warming by greenhouse gases, the U.S. government created a climate action plan in 2013. And in April 2016, representatives from 73 countries signed the paris agreement,  an international pact to combat climate change by investing in a sustainable, low-carbon future, according to the united nations framework convention on climate change  (UNFCCC). The U.S. was included among the countries that agreed to the accord in 2016, but began proceedings to withdraw from the paris agreement  in June 2017.

According to the EPA, greenhouse gas emissions were 12 percent lower in 2016 than in 2005, in part due to the large decrease in fossil fuel combustion resulting from the switch to natural gas from coal. The warmer winter conditions during those years also reduced the need for many homes and businesses to turn up the heat.

Researchers around the world continue to work toward finding ways to lower greenhouse gas emissions and mitigate their effects. One potential solution scientists are examining is to suck the carbon dioxide out of the atmosphere and bury it underground indefinitely, said Dina Leech, an associate professor of biological and environmental sciences at Longwood University in Virginia.

"What we can do is minimize how much carbon we put up there, and as a result, minimize the temperature change," Leech said. "However, the window of action is quickly closing."