EPA Administrator Scott Pruitt said today that due to the challenges of measuring human impact on the climate, he “would not agree that [carbon dioxide is] a primary contributor to the global warming that we see.” The science behind climate change presents a much clearer picture: burning fossil fuels such as petroleum and coal releases carbon dioxide. Atmospheric carbon dioxide has increased over time. The molecular structure of carbon dioxide enables it to trap heat in a way that warms the Earth's surface. University of Utah atmospheric scientist John Lin is available to comment on the scientific principles that underlie the connection between carbon dioxide and climate change.