The Greenhouse gas footprint, or GHG footprint, refers to the amount of greenhouse gases that are emitted during the creation of products or services. The Greenhouse gas footprint, or GHG footprint, refers to the amount of greenhouse gases that are emitted during the creation of products or services. Human activities are one of the main causes of greenhouse gas. These increase the earth's temperature and are emitted from fossil fuel usage in electricity and other byproducts of manufacturing. The major effects mainly consist of climate changes, such as extreme precipitation and acidification and warming of oceans. Climate change has been occurring since the start of the Industrial Revolution in the 1820s. Due to humans' heavy reliance on fossil fuels, energy usage, and constant deforestation, the amount of greenhouse gas in the atmosphere is increasing, which makes reducing a greenhouse gas footprint harder to achieve. However, there are several ways to reduce one's greenhouse gas footprint, such as using more energy efficient household appliances, increase usage of fuel efficient cars, and saving electricity. Greenhouse gases (GHGs) are gases that increase the temperature of the Earth due to their absorption of infrared radiation. Although some emissions are natural, the rate of which they are being produced has increased because of humans. These gases are emitted from fossil fuel usage in electricity, in heat and transportation, as well as being emitted as byproducts of manufacturing. The most common GHGs are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and many fluorinated gases. A greenhouse gas footprint is the numerical quantity of these gases that a single entity emits. The calculations can be computed ranging from a single person to the entire world. A GHG footprint can be calculated on the US Environmental Protection Agency’s (EPA) website. After entering data, a number with units of pounds of CO2 will be given. The EPA use pounds of CO2 equivalence to determine the greenhouse gas footprint. As early as the 1820s the investigation on climate change was in full swing. Joseph Fourier believed that light from the sun can enter the atmosphere, but cannot leave nearly as easily. He sought to prove that air can absorb the infrared radiation and will be given back to the Earth’s surface. Later in 1859, John Tyndall discovered that water vapor and CO2 trap heat waves given by the sun. In 1896, Svante Arrhenius tried to prove that it would take thousands of years for the industrial production of CO2 to raise the Earth’s temperature 5-6°C. But this idea was met with much skepticism throughout the early 20th century because it was oversimplified. In the mid 20th century, it was concluded that there was a 10% increase in carbon dioxide in the atmosphere over the 19th century, which resulted in slight warming. It was at this time that people believed the emissions of CO2 will increase exponentially in the future and the oceans would absorb any surplus of greenhouse gases. In 1956, Gilbert N. Plass concluded that greenhouse gas emissions will have an effect on the Earth’s temperature and argued that dismissing GHG emissions would be a mistake. Soon after, scientists from all sectors began to work together to figure out the mystery of GHG emissions and their effects. As technology advanced, it was in the 1980s that there was proof of a rise in CO2 levels. An ice core, captured through drilling, provided clear evidence that carbon dioxide levels have risen. Although some production of greenhouse gases is natural, human activity has increased the production substantially. Major industrial sources of greenhouse gasses are power plants, residential buildings, and road transportation, as well as energy industry processes and losses, iron and steel manufacturing, coal mining, and chemical and petrochemical industries. Changes in the environment also contribute the increase in greenhouse gas emission such as, deforestation, forest degradation and land use, livestock, agricultural soils and water, and wastewater. China is the largest contributor of greenhouse gas, causing up 30% of the total emissions. The United States contributes 15%, followed by the EU with 9%, then India with 7%, Russia with 5%, Japan with 4% , and other miscellaneous countries making up the remaining 30%. Although carbon dioxide (CO2) is the most prevalent gas, it is not the most damaging. Carbon dioxide is essential to life because animals release it during cellular respiration when they breathe and plants use it for photosynthesis. Carbon dioxide is released naturally by decomposition, ocean release and respiration. Humans contribute an increase of carbon dioxide emissions by burning fossil fuels, deforestation, and cement production. Methane (CH4) is largely released by coal, oil, and natural gas industries. Although methane is not mass produced like carbon dioxide, it is still very prevalent. Methane is more harmful than carbon dioxide because it traps heat better than CO2. Methane is a main component in natural gas. Recently industries as well as consumers have been using natural gas because they believe that it is better for the environment since it contains less CO2. However, this is not the case because methane is actually more harmful to the environment. Nitrous oxide (N2O) is released by fuel combustion, most of which comes from coal fired power plants, agricultural and industrial activities. Fluorinated gases include hydroflucarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6), and nitrogen trifluoride (NF3). These gases have no natural source and are solely products of human activity. The biggest cause of these sources is the usage of ozone depleting substances; such as refrigerants, aerosol, propellants, foam blowing agents, solvents, and fire retardants.