Greenhouse gases are several chemical species present in the atmosphere which have the property of trapping much of the solar radiation reflected from the Earth . When irradiated by incoming solar radiation,the atmosphere permits entry of most of the impinging energy of the solar electromagnetic spectrum; however, the spectrum of reflected sunlight is altered and has a higher fraction of long wave radiation, which is preferentially absorbed by greenhouse gases. Thus the net effect of higher concentrations of greenhouse gases is to encourage net heat buildup of the Earth’s atmosphere. Through normal heat exchange processes between the atmosphere and Earth’s surface, the temperature at the Earth’s surface is correspondingly elevated.
The steady increase in atmospheric concentrations of the three main greenhouse gases to which humans make notable contributions – carbon dioxide, methane, and nitrous oxide– is clear from the data sets for these gases over the last 420,000 years. Since the Industrial Revolution, concentrations of carbon dioxide, methane, and nitrous oxide have all risen sharply. Intensification of agriculture, fossil fuel combustion, land cover alteration to peatlands and wetlands have been the primary causes for these changes; however, all of these drivers are underlain by a root cause of the expanding global human population.
The analysis of greenhouse gas impacts on climate is the object of intense study, but is extremely complex due to the interactions of ocean currents and the diversity of carbon dioxide and methane sinks, which include forests, surface waters, peatlands and tundra. The situation is also complex since methane levels are rising faster percentagewise than carbon dioxide, and methane has approximately 30 times the greenhouse potency of carbon dioxide. The issue would be relatively simple, if all greenhouse gas emissions were merely the result of combustion processes, but production of methane is preponderantly from livestock grazing, rice farming and other non-point sources that are often linked to livelihoods of people in developing countries.
The seas in which corals and other calcifying species dwell are turning acidic, their pH slowly dropping as Earth's oceans acidify in response to increased carbon dioxide...
Greenhouse gas mitigation in agricultureLast Updated on 2014-11-17 12:04:21
Agricultural lands occupy 37% of the Earth’s land surface. Agriculture accounts for 52% and 84% of global anthropogenic methane and nitrous oxide emissions. Agricultural soils may also act as a sink or source for carbon dioxide (CO2), but the net flux is small. Many agricultural practices can potentially mitigate greenhouse gas (GHG) emissions, the most prominent of which are improved cropland and grazing land management and restoration of degraded lands and cultivated organic soils. Lower, but still significant mitigation potential is provided by water and rice management, set-aside, land use change and agroforestry, livestock management and manure management. The global technical mitigation potential from agriculture (excluding fossil fuel offsets from biomass) by 2030, considering all gases, is estimated to be ~5500-6000 megatonnes (Mt) CO2-eq. yr-1, with economic... More »
Climate Literacy- The Essential Principles of Climate SciencesLast Updated on 2014-11-15 15:52:27
View online here or download the PDF: High Resolution (14.67MB) or Low Resolution (2.92MB)
If you would like more detailed coverage of this topic please see The Climate Literacy Handbook
Climate Science Literacy is an understanding of your influence of climate and climate's influence on you and society.
understands the essential principles of Earth's climate system,
knows how to assess scientifically credible information about climate,
communicates about climate and climate change in a meaningful way, and
is able to make informed and responsible decisions with regard to actions that may affect climate.
During the 20th century, Earth's globally averaged surface temperature rose by approximately 1.08°F (0.6°C). Additional warming of more than 0.25°F (0.14°C) has been measured since 2000. Though the total increase may seem small, it... More »
Agriculture and Greenhouse GasesLast Updated on 2014-11-09 17:57:31
In both industrialized and developing nations, agricultural production of greenhouse gases (GHG) is a significant component of worldwide GHG emissions. There are major contributions to methane production from livestock grazing and rice farming, as well as incomplete combustion of petroleum products in mechanized agricultural equipment. In developing countries agricultural production of greenhouse gases is a much higher percentage of total GHG emissions than for developed countries. For example, rice farming in China and Southeast Asia and livestock grazing in several South American countries contributes proportionately more agricultural GHG than corresponding farming activity in most Western countries. Elimination of overgrazing practises and reduction of dependence of rice farming provide significant opportunities for reducing GHG emissions.
There are also large contributions to... More »
ClimateLast 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 »
U.S. Endangered Species Act and the Polar BearLast Updated on 2014-06-12 17:17:05
The Obama administration has followed the essential strategies of the administration of George W. Bush in disallowing the use of greenhouse gas control as an element of interpreting the protection of the polar bear under the U.S.Endangered Species Act.
On October 17, 2011 Federal Judge Emmet Sullivan struck down a provision of the Obama Interior Department, stating that a proper environmental review of the Interior Department's rule has not been done. The Obama administration agreed with the Bush administration, asserting that activities outside of the polar bear's habitat such as emissions from a power plant could not be controlled using the Endangered Species Act. Interior Secretary Ken Salazar was ordered by the federal court to respond to the environmental inadequacy of the Interior Department rule that denied the polar bear protection that could be afforded by... More »
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