Greenhouse gases, which also include water vapour and fluorinated gases, make the Earth a favourable place to live because they stop the Earth’s heat energy from escaping into space. Without these gases, the average temperature of the Earth’s surface would be -19℃. This is known as the greenhouse effect. Show A balancing actWhen sunlight reaches the Earth, two things can happen. The heat energy is either reflected back into space or it is absorbed by the Earth’s surface and oceans and eventually radiated back into space. Greenhouses gases in the atmosphere absorb some of this heat energy and slow or prevent its loss. A common analogy is how a blanket warms you by trapping some of your body’s heat and prevents the warmth from escaping. This balancing act between energy entering and leaving the Earth’s systems has created a relatively stable climate for thousands of years, but this is a very delicate balance. Around 300 years ago, humans started using fossil fuels, which emit greenhouse gases and cause more heat energy to be held in the atmosphere. The greenhouse gases act like extra blankets, holding in more and more warmth. The atmosphere does not exist in isolation. It interacts with other components of the Earth system. More than 90% of this extra atmospheric energy has been absorbed by our oceans. This additional energy is responsible for raising the water’s surface temperature, melting ice shelves and adding to sea level rise. Comparing greenhouse gasesAll greenhouse gases absorb energy, but different gases have different effects on warming. Carbon dioxide, methane and nitrous oxide remain in the atmosphere for long enough to allow them to mix together. As a result, the gas concentrations are about the same around the globe, regardless of the source or location of the emissions. Carbon dioxide (CO2) is the primary greenhouse gas because it is emitted in large quantities and it has a long-lasting influence. Most CO2 emissions have come from the burning of fossil fuels, but deforestation and cement production also add CO2. Over the last 300 years, atmospheric CO2 concentrations have risen by about 46% and are now at a concentration last experienced over 3 million years ago. Carbon dioxide can stay in the atmosphere for hundreds to thousands of years. The CO2 emissions we release today will continue to influence the climate for a long time to come. Methane (CH4) is the second most abundant greenhouse gas. Atmospheric concentrations have increased by about 150%, and methane is more abundant now than at any time in the last 800,000 years. Globally, the leading sources of human-influenced methane emissions are from agriculture – primarily from livestock and rice production. Methane also comes from energy production, wastewater treatment and landfills. Methane emissions only last for about 10–12 years, but they absorb a lot more heat energy than carbon dioxide. Globally, about 40% of nitrous oxide (N2O) emissions come from human activity and have increased by 15% in the last 300 years. A large proportion of these emissions come from agricultural soils as soil microbes break down urine, faeces and nitrogen fertilisers. Other sources include transportation and industry. Nitrous oxide emissions remain in the atmosphere for more than 100 years and pose a second danger – N2O can be converted to nitrogen oxides, which damage the ozone layer. Natural removal from the atmosphereAtmospheric greenhouse gases are removed by natural processes. These include chemical reactions within the atmosphere and physical exchanges between the atmosphere and the oceans. Carbon dioxide can also be removed by plants as they grow and store carbon. Forests and soils are able to absorb more carbon than they release. Related contentFind out how New Zealand scientists measure greenhouse gas emissions including micrometeorology. The atmosphere and the oceans are connected. Discover the role the ocean plays in the global carbon cycle and how CO2 is making the oceans more acidic. Useful linkGreenhouse gases are compared by a metric known as the global warming potential. AcknowledgementThis resource has been produced with the support of the Ministry for the Environment and Stats NZ. (c) Crown Copyright. Many of the chemical compounds in the earth's atmosphere act as greenhouse gases. When sunlight strikes the earth’s surface, some of it radiates back toward space as infrared radiation (heat). Greenhouse gases absorb this infrared radiation and trap its heat in the atmosphere, creating a greenhouse effect that results in global warming and climate change. Many gases exhibit these greenhouse properties. Some gases occur naturally and are also produced by human activities. Some, such as industrial gases, are exclusively human made. did youknow ? Without naturally occurring greenhouse gases, the earth would be too cold to support life as we know it. Without the greenhouse effect, the average temperature of the earth would be about -2°F rather than the 57°F we currently experience.  Source: Adapted from U.S. Environmental Protection Agency (public domain) What are the types of greenhouse gases?Several major greenhouse gases that result from human activity are included in U.S. and international estimates of greenhouse gas emissions:
Other greenhouse gases not counted in U.S. or international greenhouse gas inventories are water vapor and ozone. Water vapor is the most abundant greenhouse gas, but most scientists believe that water vapor produced directly by human activity contributes very little to the amount of water vapor in the atmosphere. Therefore, the U.S. Energy Information Administration (EIA) does not estimate emissions of water vapor. Ozone is technically a greenhouse gas, but ozone is helpful or harmful depending on where it is found in the earth's atmosphere. Ozone occurs naturally at higher elevations in the atmosphere (the stratosphere) where it blocks ultraviolet (UV) light that is harmful to plant and animal life from reaching the earth’s surface. The protective benefits of stratospheric ozone outweigh its contribution to the greenhouse effect. The United States and countries all around the world ban and control production and use of several industrial gases that destroy atmospheric ozone and create holes in the ozone layer. Learn more about ozone layer protection. At lower elevations of the atmosphere (the troposphere), ozone is harmful to human health. Learn more about ground-level ozone pollution and what is being done to reduce ozone pollution. What are the top 2 greenhouse gases?CO2 accounts for about 76 percent of total greenhouse gas emissions. Methane, primarily from agriculture, contributes 16 percent of greenhouse gas emissions and nitrous oxide, mostly from industry and agriculture, contributes 6 percent to global emissions.
What greenhouse gas is most common?Global Warming Potential (100-year): 1
In 2020, CO2 accounted for about 79% of all U.S. greenhouse gas emissions from human activities. Carbon dioxide is naturally present in the atmosphere as part of the Earth's carbon cycle (the natural circulation of carbon among the atmosphere, oceans, soil, plants, and animals).
What are 2 greenhouse gases that affect climate?Greenhouse gases include carbon dioxide, methane, nitrous oxides, and water vapor. (Water vapor, which responds physically or chemically to changes in temperature, is called a "feedback.") Scientists have determined that carbon dioxide's warming effect helps stabilize Earth's atmosphere.
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What are the two most common greenhouse gases
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