Human activities are responsible for almost all of the increase in greenhouse gases in the atmosphere over the last 150 years 1 The largest source of greenhouse gas emissions from human activities in the United States is from burning fossil fuels forA greenhouse gas (GHG or GhG) is a gas that absorbs and emits radiant energy within the thermal infrared range, causing the greenhouse effect The primary greenhouse gases in Earth's atmosphere are water vapor (H 2 O), carbon dioxide (CO 2), methane (CH 4), nitrous oxide (N 2 O), and ozone (O 3)Without greenhouse gases, the average temperature of Earth's surface wouldGreenhouse gases from human activities are the most significant driver of observed climate change since the mid th century 1 The indicators in this chapter characterize emissions of the major greenhouse gases resulting from human activities, the concentrations of these gases in the atmosphere, and how emissions and concentrations have changed over time
Greenhouse Effect 101 Nrdc
