Present Factors

Forcing factors are environmental processes that influence Earth's climate. They may be external to Earth and its atmosphere or may be internal to the planet and its atmosphere.

Earth's annual energy budget. Values are in watts per square meter. Arrows indicate the direction of energy flow. Based on the estimates of Trenberth et al. (2008)

Bloom (2010) Global Climate Change: Convergence of Disciplines, Sinauer Assoc.

   

 External Forcing

 Human Factors

Internal Forcing

 

  • Greenhouse effect Featured Article Greenhouse effect Greenhouse effect

    The greenhouse effect is a naturally occurring process that aids in heating the Earth's surface and atmosphere. It results from the fact that certain atmospheric... More »

Recently Updated
Climate Last Updated on 2014-10-01 10:48:54 Climate is the typical pattern of conditions of the earth’s atmosphere over a given region, as defined by factors such as temperature, air pressure. humidity, precipitation, sunlight, cloudiness, and winds. The World Meteorological Organization defines climate as "the statistical description in terms of the mean and variability of relevant quantities over a period of time," where an appropriate period is typically at least thirty years. Climate can be assessed at different, overlapping geographic regions. For example, Earth is thought to have a climate that is distinct from that of other planets, while different regions of Earth are also thought to have distinct climate types. Climate is often described as the "average" conditions; however, since daily and seasonal variability (including extremes) are critical determinants, using the term... More »
State of the Climate in 2011 Last Updated on 2012-07-11 00:00:00 Worldwide, 2011 was the coolest year on record since 2008, yet temperatures remained above the 30 year average, according to the 2011 State of the Climate report released online by the National Oceanic and Atmospheric Administration (NOAA). Back-to-back La Niñas cooled globe and influenced extreme weather in 2011 NOAA-led report examines climate conditions experienced around the world The lead character of the 2011 climate story was a double dip La Niña, which chilled the Pacific at the start and end of the year. Many of the 2011 seasonal climate patterns around the world were consistent with common side effects of La Niña. More information. Worldwide, 2011 was the coolest year on record since 2008, yet temperatures remained above the 30 year average, according to the 2011 State of the Climate report released online today by NOAA. The... More »
Module: Recent Climate Change Last Updated on 2011-08-04 00:00:00 Summary   This is a data-driven module designed to address key questions about the stability of the Earth’s climate in the past and the factors that drive climate change. This information is essential for students who want to study current climate change using NASA data, and interprets this in a correct historical context Goals   ·       Students will investigate how land surface and ocean surface temperatures have changed since 1840. ·       This exercise asks students to consider two contrasting interpretations of climate change over the last 2,000 years. ·       Both interpretations use a range of proxy data, but the Loehle data specifically excludes tree ring data. Investigate how the level of CO2 level in the... More »
Methane: Greenhouse Gas Enemy Number Two Last Updated on 2010-12-16 00:00:00 Methane (CH4) is second only to carbon dioxide (CO2) in its contribution to the greenhouse effect and accounts for about 15% of anthropogenic warming. [1] Moreover, sudden release of CH4 from the melting of seabed methane hydrate is implicated in such cataclysmic events as the Great Dying and the Late Paleocene Thermal Maximum. Once in the atmosphere, CH4 oxidizes to CO2 in about a dozen years. Contrary to popular belief, the majority of humans do not release CH4 when they pass flatus gas [2] — this provides yet another reason why attempts to ignite these emissions are seldom worthwhile. Other human activities, however, do emit large amounts of CH4. Over 75% of the world’s rice is grown in flooded paddies. Soils during flooding soon become anaerobic, and soil microbes generate CH4, or “marsh gas,” through anaerobic respiration. Clearing of agricultural... More »
Lecture: Stephen Schneider Climate Change Mitigation and Adaptation Video Last Updated on 2010-10-07 00:00:00 This video is of a lecture that Stephen Schneider presented a number of times. It covers climate change from a risk perspective, discussing the underlying science, uncertainties, and implications of different possible decisions. Here is it captured with many (although not all) of his graphics. It is a well organized, evenly presented lecture that carefully differentiates questions of "what we know" from "what we should do." It presents data and modelling at a level appropriate for undergraduates. More »