Are humans causing or contributing to global warming?

Author: 
January 23, 2014

Yes, human activities have increased the abundance of heat-trapping gases in the atmosphere, which a large majority of climate scientists agree is the main reason for the 1.5°F (0.85°C) rise in average global temperature since 1880. Carbon dioxide is the heat-trapping gas primarily responsible for the rise but methane, nitrous oxide, ozone, and various other very long-lived heat-trapping gases also contribute. Carbon dioxide is of greatest concern because its rate of increase is exerting a larger overall warming influence than all of those other gases combined, and because carbon dioxide levels in the atmosphere will remain elevated for centuries unless we implement a way to remove carbon dioxide from the atmosphere effectively and economically. Most carbon dioxide from human activities is released from burning coal and other fossil fuels. Other human activities, including deforestation, biomass burning, and cement production also produce carbon dioxide.

Intermountain Power Plant

Steam billows from the Intermountain Power Plant in Delta, Utah. This coal-fired plant is operated by the Los Angeles Department of Water and Power. Photo CC license by Matt Hintsa.

References

USGCRP (2009): Global Climate Change Impacts in the United States. A special report of the United States Global Change Research Program [T.R. Karl, J.M. Melillo, and T.C. Peterson (eds.)]. Cambridge University Press, New York, NY, USA, 188 pp.

IPCC (2007): Climate Change 2007: The Physical Science Basis. Contribution of Working Group 1 to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor, and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 996 pp.