Greenhouse gases play an essential role in regulating the Earth's energy balance. Greenhouse gases are a group of naturally occurring compounds such as carbon dioxide, water vapor, methane, nitrous oxide and ozone, capable of trapping heat in the atmosphere, maintaining the surface of the Earth warmer than it would be if these compounds were not there. Natural gases are the essential cause of the greenhouse effect. An increase in the amount of gases in the atmosphere strengthens the greenhouse effect, creating global warming and therefore climate change. Climate change poses one of the most significant threats facing the world today. However, concern and awareness regarding greenhouse gases was not vital until global warming and climate change affected all living things on the plant as well as our planet itself. Author William Nordhaus of Yale University has reached consensus on the likelihood of significant warming in the coming century. Since 1997, after the first Kyoto agreement, countries have taken very limited steps to reduce greenhouse gas emissions. There are many reasons why greenhouse gases have increased, such as deforestation of rainforests, which is vital since trees absorb carbon dioxide. With fewer trees, more carbon dioxide accumulates in the atmosphere. The use and burning of fossil fuels releases greenhouse gases as they burn and emit carbon dioxide into the atmosphere or even population growth, which contributes to the high supply and demand of food, livestock, land, energy and water. However, it is up to major countries to change their ecological footprint to eliminate the growing impact of greenhouse gases. Author William Nordhaus of Yale University led a study that examines alternative outcomes for emissions, climate...... middle of article ......w 2 degrees Celsius could not be enough and it is possible to aim to maintain it below 1.5 degrees. However, G8 leaders said that to reach the 2 degree target, they would need to reduce their greenhouse gas emissions by 80% by 2050. The Copenhagen Accord allows the world's nations to contribute to the goal of having a cleaner, safer and fresher living environment and planet. The Copenhagen Accord also requires all parties, including the United States, the United Nations, China, India, South Africa, Brazil and other countries, to submit their individual targets for reducing emissions. These registrations will be classified according to the two annexes attached to the agreement: Annex I parties and non-Annex I parties. Annex I parties will require a submission on the reduction target emissions for 2020. While non-Annex I parties will submit their individual plans to specify their plan to reduce greenhouse gas emissions..