The electric car is a vehicle that utilizes chemical energy stored in rechargeable battery packs, and electric motors and motor controllers instead of an internal combustion engine (ICE).
Vehicles using both electric motors and ICEs (hybrid electric vehicles) are examples of hybrid vehicles, and are not considered pure electric vehicles (EVs) because they operate in a charge-sustaining mode. Hybrid vehicles with batteries that can be charged externally to displace some or all of their ICE power and gasoline fuel are called plug-in hybrid electric vehicles (PHEV), and are pure battery electric vehicles (BEVs) during their charge-depleting mode. Electric vehicles include automobiles, light trucks, and neighborhood electric vehicles.
Electric cars were among the earliest automobiles. They produce no exhaust fumes, and minimal pollution if charged from most forms of renewable energy. Many are capable of acceleration exceeding that of conventional vehicles, are quiet, and do not produce noxious fumes. Electric cars reduce dependence on petroleum and decrease or eliminate greenhouse gas emissions, depending on how their electricity is produced.
Historically, EVs and PHEVs have had issues with high battery costs, limited travel distance between battery recharging, charging time, and battery lifespan, which have limited widespread adoption. Ongoing battery technology advancements have addressed many of these problems; many models have recently been prototyped, and a handful of future production models have been announced. Toyota, Honda, Ford and General Motors all produced electric cars in the 1990s in order to comply with the California Air Resources Board's Zero Emission Vehicle Mandate. The major US automobile manufacturers have been accused of deliberately sabotaging their electric vehicle production efforts.[1][2]
Electric cars are expected to be cheaper to make and maintain than internal combustion engine vehicles because they have many fewer parts[citation needed]. Using regenerative braking, a feature which is standard on many electric and hybrid vehicles, a significant portion of the energy expended during acceleration may be recovered during braking, increasing the efficiency of the vehicle.[3][4]
In general terms an electric car is a rechargeable battery electric vehicle. Other examples of rechargeable electric vehicles are ones that store electricity in ultracapacitors, or in a flywheel.
From Wikipedia, the free encyclopedia
Showing posts with label Article. Show all posts
Showing posts with label Article. Show all posts
Wednesday, May 7, 2008
Saturday, May 3, 2008
OfficeMax Unveils Line of TerraCycle's Made-from-Waste Office Products
By GreenerDesign Staff, GreenerDesign
Published May 2, 2008
NAPERVILLE, Ill. -- The pencil cases in OfficeMax's newest retail offerings may look surprisingly familiar, even nostalgic to some shoppers. The cases are made from discarded containers of Capri Sun, the juice pouch more frequently seen on playgrounds than on end-caps.
The cases are just one of the new products for sale at OfficeMax stores nationwide created by TerraCycle, a company making innovative products from "waste-stream" materials like juice packages, plastic bottles and e-waste. Among the other products that OfficeMax announced it would carry include binders made from 100 percent reused cardboard, trash cans made from recycled e-waste plastic, and non-toxic cleaning products packaged in old soda bottles.
In addition to diverting materials from the waste stream, TerraCycle's products also aim to give back to the community as well as the environment. The Capri Sun pouches used in the pencil cases, for instance, are collected as fundraisers at schools; TerraCycle pays the schools two cents per pouch, and then turns what would otherwise be garbage into a new product.
The new line of products on sale at OfficeMax is TerraCycle's opening foray into the realm of office products. TerraCycle first made waves in 2007 when it was sued by Scott's Miracle-Gro for what that company said were misleading claims for its flagship product, its worm poop fertilizers. The two companies settled the complaint in September.
TerraCycle and OfficeMax plan to work together on introducing more products to shoppers, as well as furthering fundraising and educational efforts around reuse and recycling of waste products.
Published May 2, 2008
NAPERVILLE, Ill. -- The pencil cases in OfficeMax's newest retail offerings may look surprisingly familiar, even nostalgic to some shoppers. The cases are made from discarded containers of Capri Sun, the juice pouch more frequently seen on playgrounds than on end-caps.
The cases are just one of the new products for sale at OfficeMax stores nationwide created by TerraCycle, a company making innovative products from "waste-stream" materials like juice packages, plastic bottles and e-waste. Among the other products that OfficeMax announced it would carry include binders made from 100 percent reused cardboard, trash cans made from recycled e-waste plastic, and non-toxic cleaning products packaged in old soda bottles.
In addition to diverting materials from the waste stream, TerraCycle's products also aim to give back to the community as well as the environment. The Capri Sun pouches used in the pencil cases, for instance, are collected as fundraisers at schools; TerraCycle pays the schools two cents per pouch, and then turns what would otherwise be garbage into a new product.
The new line of products on sale at OfficeMax is TerraCycle's opening foray into the realm of office products. TerraCycle first made waves in 2007 when it was sued by Scott's Miracle-Gro for what that company said were misleading claims for its flagship product, its worm poop fertilizers. The two companies settled the complaint in September.
TerraCycle and OfficeMax plan to work together on introducing more products to shoppers, as well as furthering fundraising and educational efforts around reuse and recycling of waste products.
Friday, April 25, 2008
Rainforest Facts
Tropical rainforests - where and what are they?
Tropical rainforests are found across the world between the Tropic of Cancer, at approximately 23 degrees north, and the Tropic of Capricorn, at 23 degrees south of the Equator. They are found in Asia, Africa, Northern Australia, South America and many tropical islands. The areas where rainforests occur experience a constant climate with high temperatures averaging 25°C all year round, an average annual rainfall of at least 2 metres, and up to 100% humidity. Some rainforests get as much as 10 metres of rain per year! Tropical rainforests cover 2% of the world’s land surface - an area of 2000 million hectares - and yet contain over half of the earth’s species of animals and plants. The largest rainforest, called the Amazon, is found in South America and spans eight countries, covering a total area of 2 million square miles.
The forest canopy
The rainforest canopy is divided into four main layers: the emergent layer consists of the tallest trees (emergent trees) which can grow to heights of 70m. These trees act as a buffer, sheltering the lower trees from heavy rains. Beneath this layer is the main canopy of smaller trees which are intertwined with climbing vines and hold flowering plants, called epiphytes, on their branches. Below this is the understorey containing young saplings and shrubs. The final layer, the dark forest floor contains only a few plants as only 2% of the sunlight reaches this layer of the forest, making it difficult for plants to grow.
From Rainforest Concern
Tropical rainforests are found across the world between the Tropic of Cancer, at approximately 23 degrees north, and the Tropic of Capricorn, at 23 degrees south of the Equator. They are found in Asia, Africa, Northern Australia, South America and many tropical islands. The areas where rainforests occur experience a constant climate with high temperatures averaging 25°C all year round, an average annual rainfall of at least 2 metres, and up to 100% humidity. Some rainforests get as much as 10 metres of rain per year! Tropical rainforests cover 2% of the world’s land surface - an area of 2000 million hectares - and yet contain over half of the earth’s species of animals and plants. The largest rainforest, called the Amazon, is found in South America and spans eight countries, covering a total area of 2 million square miles.
The forest canopy
The rainforest canopy is divided into four main layers: the emergent layer consists of the tallest trees (emergent trees) which can grow to heights of 70m. These trees act as a buffer, sheltering the lower trees from heavy rains. Beneath this layer is the main canopy of smaller trees which are intertwined with climbing vines and hold flowering plants, called epiphytes, on their branches. Below this is the understorey containing young saplings and shrubs. The final layer, the dark forest floor contains only a few plants as only 2% of the sunlight reaches this layer of the forest, making it difficult for plants to grow.
From Rainforest Concern
Related climatic issues
Main articles: Ocean acidification, global dimming, and ozone depletion
A variety of issues are often raised in relation to global warming. One is ocean acidification. Increased atmospheric CO2 increases the amount of CO2 dissolved in the oceans. CO2 dissolved in the ocean reacts with water to form carbonic acid, resulting in acidification. Ocean surface pH is estimated to have decreased from 8.25 near the beginning of the industrial era to 8.14 by 2004, and is projected to decrease by a further 0.14 to 0.5 units by 2100 as the ocean absorbs more CO2. Since organisms and ecosystems are adapted to a narrow range of pH, this raises extinction concerns, directly driven by increased atmospheric CO2, that could disrupt food webs and impact human societies that depend on marine ecosystem services.
Global dimming, the gradual reduction in the amount of global direct irradiance at the Earth's surface, may have partially mitigated global warming in the late twentieth century. From 1960 to 1990 human-caused aerosols likely precipitated this effect. Scientists have stated with 66–90% confidence that the effects of human-caused aerosols, along with volcanic activity, have offset some of the global warming, and that greenhouse gases would have resulted in more warming than observed if not for these dimming agents.
Ozone depletion, the steady decline in the total amount of ozone in Earth's stratosphere, is frequently cited in relation to global warming. Although there are areas of linkage, the relationship between the two is not strong.
From Wikipedia, The Free Encyclopedia
A variety of issues are often raised in relation to global warming. One is ocean acidification. Increased atmospheric CO2 increases the amount of CO2 dissolved in the oceans. CO2 dissolved in the ocean reacts with water to form carbonic acid, resulting in acidification. Ocean surface pH is estimated to have decreased from 8.25 near the beginning of the industrial era to 8.14 by 2004, and is projected to decrease by a further 0.14 to 0.5 units by 2100 as the ocean absorbs more CO2. Since organisms and ecosystems are adapted to a narrow range of pH, this raises extinction concerns, directly driven by increased atmospheric CO2, that could disrupt food webs and impact human societies that depend on marine ecosystem services.
Global dimming, the gradual reduction in the amount of global direct irradiance at the Earth's surface, may have partially mitigated global warming in the late twentieth century. From 1960 to 1990 human-caused aerosols likely precipitated this effect. Scientists have stated with 66–90% confidence that the effects of human-caused aerosols, along with volcanic activity, have offset some of the global warming, and that greenhouse gases would have resulted in more warming than observed if not for these dimming agents.
Ozone depletion, the steady decline in the total amount of ozone in Earth's stratosphere, is frequently cited in relation to global warming. Although there are areas of linkage, the relationship between the two is not strong.
From Wikipedia, The Free Encyclopedia
Adaptation and mitigation
Main articles: Adaptation to global warming, Mitigation of global warming, and Kyoto Protocol
among climate scientists that global temperatures will continue to increase has led some nations, states, corporations and individuals to implement actions to try to curtail global warming or adjust to it. Many environmental groups encourage individual action against global warming, often by the consumer, but also by community and regional organizations. Others have suggested a quota on worldwide fossil fuel production, citing a direct link between fossil fuel production and CO2 emissions.
There has also been business action on climate change, including efforts at increased energy efficiency and limited moves towards use of alternative fuels. One important innovation has been the development of greenhouse gas emissions trading through which companies, in conjunction with government, agree to cap their emissions or to purchase credits from those below their allowances.
The world's primary international agreement on combating global warming is the Kyoto Protocol, an amendment to the UNFCCC negotiated in 1997. The Protocol now covers more than 160 countries globally and over 55% of global greenhouse gas emissions. Only the United States and Kazakhstan have not ratified the treaty, with the United States historically being the world's largest emitter of greenhouse gas. This treaty expires in 2012, and international talks began in May 2007 on a future treaty to succeed the current one.
Claiming "serious harm" to the United States economy and the exemption of "80 percent of the world, including major population centers" like China and India from the treaty, George W. Bush contends that the Kyoto Protocol is an unfair and ineffective means of addressing global climate change concerns. Bush has promoted improved energy technology as a means to combat climate change, and various state and city governments within the United States have begun their own initiatives to indicate support and compliance with the Kyoto Protocol on a local basis; an example of this being the Regional Greenhouse Gas Initiative.
China and India, though exempt from its provisions as developing countries, have ratified the Kyoto Protocol. China may have passed the U.S. in total annual greenhouse gas emissions according to some recent studies. Chinese Premier Wen Jiabao has called on the nation to redouble its efforts to tackle pollution and global warming.
The IPCC's Working Group III is responsible for crafting reports that deal with the mitigation of global warming and analyzing the costs and benefits of different approaches. In the 2007 IPCC Fourth Assessment Report, they conclude that no one technology or sector can be completely responsible for mitigating future warming. They find there are key practices and technologies in various sectors, such as energy supply, transportation, industry, and agriculture, that should be implemented to reduced global emissions. They estimate that stabilization of carbon dioxide equivalent between 445 and 710 ppm by 2030 will result in between a 0.6% increase and 3% decrease in global gross domestic product.
From Wikipedia, The Free Encyclopedia
among climate scientists that global temperatures will continue to increase has led some nations, states, corporations and individuals to implement actions to try to curtail global warming or adjust to it. Many environmental groups encourage individual action against global warming, often by the consumer, but also by community and regional organizations. Others have suggested a quota on worldwide fossil fuel production, citing a direct link between fossil fuel production and CO2 emissions.
There has also been business action on climate change, including efforts at increased energy efficiency and limited moves towards use of alternative fuels. One important innovation has been the development of greenhouse gas emissions trading through which companies, in conjunction with government, agree to cap their emissions or to purchase credits from those below their allowances.
The world's primary international agreement on combating global warming is the Kyoto Protocol, an amendment to the UNFCCC negotiated in 1997. The Protocol now covers more than 160 countries globally and over 55% of global greenhouse gas emissions. Only the United States and Kazakhstan have not ratified the treaty, with the United States historically being the world's largest emitter of greenhouse gas. This treaty expires in 2012, and international talks began in May 2007 on a future treaty to succeed the current one.
Claiming "serious harm" to the United States economy and the exemption of "80 percent of the world, including major population centers" like China and India from the treaty, George W. Bush contends that the Kyoto Protocol is an unfair and ineffective means of addressing global climate change concerns. Bush has promoted improved energy technology as a means to combat climate change, and various state and city governments within the United States have begun their own initiatives to indicate support and compliance with the Kyoto Protocol on a local basis; an example of this being the Regional Greenhouse Gas Initiative.
China and India, though exempt from its provisions as developing countries, have ratified the Kyoto Protocol. China may have passed the U.S. in total annual greenhouse gas emissions according to some recent studies. Chinese Premier Wen Jiabao has called on the nation to redouble its efforts to tackle pollution and global warming.
The IPCC's Working Group III is responsible for crafting reports that deal with the mitigation of global warming and analyzing the costs and benefits of different approaches. In the 2007 IPCC Fourth Assessment Report, they conclude that no one technology or sector can be completely responsible for mitigating future warming. They find there are key practices and technologies in various sectors, such as energy supply, transportation, industry, and agriculture, that should be implemented to reduced global emissions. They estimate that stabilization of carbon dioxide equivalent between 445 and 710 ppm by 2030 will result in between a 0.6% increase and 3% decrease in global gross domestic product.
From Wikipedia, The Free Encyclopedia
Wednesday, April 23, 2008
Attributed and expected effects
Main article: Effects of global warming
Although it is difficult to connect specific weather events to global warming, an increase in global temperatures may in turn cause broader changes, including glacial retreat, Arctic shrinkage, and worldwide sea level rise. Changes in the amount and pattern of precipitation may result in flooding and drought. There may also be changes in the frequency and intensity of extreme weather events. Other effects may include changes in agricultural yields, addition of new trade routes, reduced summer streamflows, species extinctions, and increases in the range of disease vectors.
Some effects on both the natural environment and human life are, at least in part, already being attributed to global warming. A 2001 report by the IPCC suggests that glacier retreat, ice shelf disruption such as that of the Larsen Ice Shelf, sea level rise, changes in rainfall patterns, and increased intensity and frequency of extreme weather events, are being attributed in part to global warming. While changes are expected for overall patterns, intensity, and frequencies, it is difficult to attribute specific events to global warming. Other expected effects include water scarcity in some regions and increased precipitation in others, changes in mountain snowpack, and adverse health effects from warmer temperatures.
Increasing deaths, displacements, and economic losses projected due to extreme weather attributed to global warming may be exacerbated by growing population densities in affected areas, although temperate regions are projected to experience some benefits, such as fewer deaths due to cold exposure. A summary of probable effects and recent understanding can be found in the report made for the IPCC Third Assessment Report by Working Group II. The newer IPCC Fourth Assessment Report summary reports that there is observational evidence for an increase in intense tropical cyclone activity in the North Atlantic Ocean since about 1970, in correlation with the increase in sea surface temperature, but that the detection of long-term trends is complicated by the quality of records prior to routine satellite observations. The summary also states that there is no clear trend in the annual worldwide number of tropical cyclones.
Additional anticipated effects include sea level rise of 110 to 770 millimeters (0.36 to 2.5 ft) between 1990 and 2100, repercussions to agriculture, possible slowing of the thermohaline circulation, reductions in the ozone layer, increased intensity of hurricanes and extreme weather events, lowering of ocean pH, and the spread of diseases such as malaria and dengue fever. One study predicts 18% to 35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections.However, few mechanistic studies have documented extinctions due to recent climate change and one study suggests that projected rates of extinction are uncertain.
From Wikipedia, the free encyclopedia
Although it is difficult to connect specific weather events to global warming, an increase in global temperatures may in turn cause broader changes, including glacial retreat, Arctic shrinkage, and worldwide sea level rise. Changes in the amount and pattern of precipitation may result in flooding and drought. There may also be changes in the frequency and intensity of extreme weather events. Other effects may include changes in agricultural yields, addition of new trade routes, reduced summer streamflows, species extinctions, and increases in the range of disease vectors.
Some effects on both the natural environment and human life are, at least in part, already being attributed to global warming. A 2001 report by the IPCC suggests that glacier retreat, ice shelf disruption such as that of the Larsen Ice Shelf, sea level rise, changes in rainfall patterns, and increased intensity and frequency of extreme weather events, are being attributed in part to global warming. While changes are expected for overall patterns, intensity, and frequencies, it is difficult to attribute specific events to global warming. Other expected effects include water scarcity in some regions and increased precipitation in others, changes in mountain snowpack, and adverse health effects from warmer temperatures.
Increasing deaths, displacements, and economic losses projected due to extreme weather attributed to global warming may be exacerbated by growing population densities in affected areas, although temperate regions are projected to experience some benefits, such as fewer deaths due to cold exposure. A summary of probable effects and recent understanding can be found in the report made for the IPCC Third Assessment Report by Working Group II. The newer IPCC Fourth Assessment Report summary reports that there is observational evidence for an increase in intense tropical cyclone activity in the North Atlantic Ocean since about 1970, in correlation with the increase in sea surface temperature, but that the detection of long-term trends is complicated by the quality of records prior to routine satellite observations. The summary also states that there is no clear trend in the annual worldwide number of tropical cyclones.
Additional anticipated effects include sea level rise of 110 to 770 millimeters (0.36 to 2.5 ft) between 1990 and 2100, repercussions to agriculture, possible slowing of the thermohaline circulation, reductions in the ozone layer, increased intensity of hurricanes and extreme weather events, lowering of ocean pH, and the spread of diseases such as malaria and dengue fever. One study predicts 18% to 35% of a sample of 1,103 animal and plant species would be extinct by 2050, based on future climate projections.However, few mechanistic studies have documented extinctions due to recent climate change and one study suggests that projected rates of extinction are uncertain.
From Wikipedia, the free encyclopedia
Tuesday, April 22, 2008
Climate models
Calculations of global warming prepared in or before 2001 from a range of climate models under the SRES A2 emissions scenario, which assumes no action is taken to reduce emissions.
The geographic distribution of surface warming during the 21st century calculated by the HadCM3 climate model if a business as usual scenario is assumed for economic growth and greenhouse gas emissions. In this figure, the globally averaged warming corresponds to 3.0 °C (5.4 °F).
Scientists have studied global warming with computer models of the climate. These models are based on physical principles of fluid dynamics, radiative transfer, and other processes, with simplifications being necessary because of limitations in computer power and the complexity of the climate system. All modern climate models include an atmospheric model that is coupled to an ocean model and models for ice cover on land and sea. Some models also include treatments of chemical and biological processes. These models predict that the effect of adding greenhouse gases is to produce a warmer climate. However, even when the same assumptions of future greenhouse gas levels are used, there still remains a considerable range of climate sensitivity.
Including uncertainties in future greenhouse gas concentrations and climate modeling, the IPCC anticipates a warming of 1.1 °C to 6.4 °C (2.0 °F to 11.5 °F) by the end of the 21st century, relative to 1980–1999. Models have also been used to help investigate the causes of recent climate change by comparing the observed changes to those that the models project from various natural and human-derived causes.
Current climate models produce a good match to observations of global temperature changes over the last century, but do not simulate all aspects of climate. These models do not unambiguously attribute the warming that occurred from approximately 1910 to 1945 to either natural variation or human effects; however, they suggest that the warming since 1975 is dominated by man-made greenhouse gas emissions.
Global climate model projections of future climate are forced by imposed greenhouse gas emission scenarios, most often from the IPCC Special Report on Emissions Scenarios (SRES). Less commonly, models may also include a simulation of the carbon cycle; this generally shows a positive feedback, though this response is uncertain (under the A2 SRES scenario, responses vary between an extra 20 and 200 ppm of CO2). Some observational studies also show a positive feedback.
The representation of clouds is one of the main sources of uncertainty in present-generation models, though progress is being made on this problem.
From Wikipedia, the free encyclopedia
The geographic distribution of surface warming during the 21st century calculated by the HadCM3 climate model if a business as usual scenario is assumed for economic growth and greenhouse gas emissions. In this figure, the globally averaged warming corresponds to 3.0 °C (5.4 °F).
Scientists have studied global warming with computer models of the climate. These models are based on physical principles of fluid dynamics, radiative transfer, and other processes, with simplifications being necessary because of limitations in computer power and the complexity of the climate system. All modern climate models include an atmospheric model that is coupled to an ocean model and models for ice cover on land and sea. Some models also include treatments of chemical and biological processes. These models predict that the effect of adding greenhouse gases is to produce a warmer climate. However, even when the same assumptions of future greenhouse gas levels are used, there still remains a considerable range of climate sensitivity.
Including uncertainties in future greenhouse gas concentrations and climate modeling, the IPCC anticipates a warming of 1.1 °C to 6.4 °C (2.0 °F to 11.5 °F) by the end of the 21st century, relative to 1980–1999. Models have also been used to help investigate the causes of recent climate change by comparing the observed changes to those that the models project from various natural and human-derived causes.
Current climate models produce a good match to observations of global temperature changes over the last century, but do not simulate all aspects of climate. These models do not unambiguously attribute the warming that occurred from approximately 1910 to 1945 to either natural variation or human effects; however, they suggest that the warming since 1975 is dominated by man-made greenhouse gas emissions.
Global climate model projections of future climate are forced by imposed greenhouse gas emission scenarios, most often from the IPCC Special Report on Emissions Scenarios (SRES). Less commonly, models may also include a simulation of the carbon cycle; this generally shows a positive feedback, though this response is uncertain (under the A2 SRES scenario, responses vary between an extra 20 and 200 ppm of CO2). Some observational studies also show a positive feedback.
The representation of clouds is one of the main sources of uncertainty in present-generation models, though progress is being made on this problem.
From Wikipedia, the free encyclopedia
Pre-human climate variations
Curves of reconstructed temperature at two locations in Antarctica and a global record of variations in glacial ice volume. Today's date is on the left side of the graph.
Earth has experienced warming and cooling many times in the past. The recent Antarctic EPICA ice core spans 800,000 years, including eight glacial cycles timed by orbital variations with interglacial warm periods comparable to present temperatures.
A rapid buildup of greenhouse gases amplified warming in the early Jurassic period (about 180 million years ago), with average temperatures rising by 5 °C (9 °F). Research by the Open University indicates that the warming caused the rate of rock weathering to increase by 400%. As such weathering locks away carbon in calcite and dolomite, CO2 levels dropped back to normal over roughly the next 150,000 years.
Sudden releases of methane from clathrate compounds (the clathrate gun hypothesis) have been hypothesized as both a cause for and an effect of other warming events in the distant past, including the Permian–Triassic extinction event (about 251 million years ago) and the Paleocene–Eocene Thermal Maximum (about 55 million years ago).
From Wikipedia, the free encyclopedia
Earth has experienced warming and cooling many times in the past. The recent Antarctic EPICA ice core spans 800,000 years, including eight glacial cycles timed by orbital variations with interglacial warm periods comparable to present temperatures.
A rapid buildup of greenhouse gases amplified warming in the early Jurassic period (about 180 million years ago), with average temperatures rising by 5 °C (9 °F). Research by the Open University indicates that the warming caused the rate of rock weathering to increase by 400%. As such weathering locks away carbon in calcite and dolomite, CO2 levels dropped back to normal over roughly the next 150,000 years.
Sudden releases of methane from clathrate compounds (the clathrate gun hypothesis) have been hypothesized as both a cause for and an effect of other warming events in the distant past, including the Permian–Triassic extinction event (about 251 million years ago) and the Paleocene–Eocene Thermal Maximum (about 55 million years ago).
From Wikipedia, the free encyclopedia
Temperature changes
Main article: Temperature record
Recent
Global temperatures on both land and sea have increased by 0.75 °C (1.35 °F) relative to the period 1860–1900, according to the instrumental temperature record. This measured temperature increase is not significantly affected by the urban heat island effect. Since 1979, land temperatures have increased about twice as fast as ocean temperatures (0.25 °C per decade against 0.13 °C per decade). Temperatures in the lower troposphere have increased between 0.12 and 0.22 °C (0.22 and 0.4 °F) per decade since 1979, according to satellite temperature measurements. Temperature is believed to have been relatively stable over the one or two thousand years before 1850, with possibly regional fluctuations such as the Medieval Warm Period or the Little Ice Age.
Sea temperatures increase more slowly than those on land both because of the larger effective heat capacity of the oceans and because the ocean can lose heat by evaporation more readily than the land. The Northern Hemisphere has more land than the Southern Hemisphere, so it warms faster. The Northern Hemisphere also has extensive areas of seasonal snow and sea-ice cover subject to the ice-albedo feedback. More greenhouse gases are emitted in the Northern than Southern Hemisphere, but this does not contribute to the difference in warming because the major greenhouse gases persist long enough to mix between hemispheres.
Based on estimates by NASA's Goddard Institute for Space Studies, 2005 was the warmest year since reliable, widespread instrumental measurements became available in the late 1800s, exceeding the previous record set in 1998 by a few hundredths of a degree. Estimates prepared by the World Meteorological Organization and the Climatic Research Unit concluded that 2005 was the second warmest year, behind 1998. Temperatures in 1998 were unusually warm because the strongest El Niño in the past century occurred during that year.
Anthropogenic emissions of other pollutants—notably sulfate aerosols—can exert a cooling effect by increasing the reflection of incoming sunlight. This partially accounts for the cooling seen in the temperature record in the middle of the twentieth century, though the cooling may also be due in part to natural variability. James Hansen and colleagues have proposed that the effects of the products of fossil fuel combustion—CO2 and aerosols—have largely offset one another, so that warming in recent decades has been driven mainly by non-CO2 greenhouse gases.
Paleoclimatologist William Ruddiman has argued that human influence on the global climate began around 8,000 years ago with the start of forest clearing to provide land for agriculture and 5,000 years ago with the start of Asian rice irrigation. Ruddiman's interpretation of the historical record, with respect to the methane data, has been disputed.
From Wikipedia, the free encyclopedia
Recent
Global temperatures on both land and sea have increased by 0.75 °C (1.35 °F) relative to the period 1860–1900, according to the instrumental temperature record. This measured temperature increase is not significantly affected by the urban heat island effect. Since 1979, land temperatures have increased about twice as fast as ocean temperatures (0.25 °C per decade against 0.13 °C per decade). Temperatures in the lower troposphere have increased between 0.12 and 0.22 °C (0.22 and 0.4 °F) per decade since 1979, according to satellite temperature measurements. Temperature is believed to have been relatively stable over the one or two thousand years before 1850, with possibly regional fluctuations such as the Medieval Warm Period or the Little Ice Age.
Sea temperatures increase more slowly than those on land both because of the larger effective heat capacity of the oceans and because the ocean can lose heat by evaporation more readily than the land. The Northern Hemisphere has more land than the Southern Hemisphere, so it warms faster. The Northern Hemisphere also has extensive areas of seasonal snow and sea-ice cover subject to the ice-albedo feedback. More greenhouse gases are emitted in the Northern than Southern Hemisphere, but this does not contribute to the difference in warming because the major greenhouse gases persist long enough to mix between hemispheres.
Based on estimates by NASA's Goddard Institute for Space Studies, 2005 was the warmest year since reliable, widespread instrumental measurements became available in the late 1800s, exceeding the previous record set in 1998 by a few hundredths of a degree. Estimates prepared by the World Meteorological Organization and the Climatic Research Unit concluded that 2005 was the second warmest year, behind 1998. Temperatures in 1998 were unusually warm because the strongest El Niño in the past century occurred during that year.
Anthropogenic emissions of other pollutants—notably sulfate aerosols—can exert a cooling effect by increasing the reflection of incoming sunlight. This partially accounts for the cooling seen in the temperature record in the middle of the twentieth century, though the cooling may also be due in part to natural variability. James Hansen and colleagues have proposed that the effects of the products of fossil fuel combustion—CO2 and aerosols—have largely offset one another, so that warming in recent decades has been driven mainly by non-CO2 greenhouse gases.
Paleoclimatologist William Ruddiman has argued that human influence on the global climate began around 8,000 years ago with the start of forest clearing to provide land for agriculture and 5,000 years ago with the start of Asian rice irrigation. Ruddiman's interpretation of the historical record, with respect to the methane data, has been disputed.
From Wikipedia, the free encyclopedia
Terminology
Terminology
The term "global warming" is a specific example of global climate change. The term "climate change" can also refer to other periods of overall temperature change such as global cooling. In common usage, the term "global warming" refers to the warming in recent decades and its projected continuation, and implies a human influence. The United Nations Framework Convention on Climate Change (UNFCCC) uses the term "climate change" for human-caused change, and "climate variability" for other changes. The term "anthropogenic global warming" (AGW) is sometimes used when focusing on human-induced changes.
From Wikipedia, the free encyclopedia
The term "global warming" is a specific example of global climate change. The term "climate change" can also refer to other periods of overall temperature change such as global cooling. In common usage, the term "global warming" refers to the warming in recent decades and its projected continuation, and implies a human influence. The United Nations Framework Convention on Climate Change (UNFCCC) uses the term "climate change" for human-caused change, and "climate variability" for other changes. The term "anthropogenic global warming" (AGW) is sometimes used when focusing on human-induced changes.
From Wikipedia, the free encyclopedia
Global Warming
Global warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-twentieth century and its projected continuation.
The average global air temperature near the Earth's surface increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the hundred years ending in 2005. The Intergovernmental Panel on Climate Change (IPCC) concludes "most of the observed increase in globally averaged temperatures since the mid-twentieth century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations" via the greenhouse effect.
Natural phenomena such as solar variation combined with volcanoes probably had a small warming effect from pre-industrial times to 1950 and a small cooling effect from 1950 onward. These basic conclusions have been endorsed by at least thirty scientific societies and academies of science, including all of the national academies of science of the major industrialized countries. While individual scientists have voiced disagreement with some findings of the IPCC, the overwhelming majority of scientists working on climate change agree with the IPCC's main conclusions.
Climate model projections summarized by the IPCC indicate that average global surface temperature will likely rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the twenty-first century. The range of values results from the use of differing scenarios of future greenhouse gas emissions as well as models with differing climate sensitivity. Although most studies focus on the period up to 2100, warming and sea level rise are expected to continue for more than a thousand years even if greenhouse gas levels are stabilized. The delay in reaching equilibrium is a result of the large heat capacity of the oceans.
Increasing global temperature will cause sea level to rise, and is expected to increase the intensity of extreme weather events and to change the amount and pattern of precipitation. Other effects of global warming include changes in agricultural yields, trade routes, glacier retreat, species extinctions and increases in the ranges of disease vectors.
Remaining scientific uncertainties include the amount of warming expected in the future, and how warming and related changes will vary from region to region around the globe. Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions, but there is ongoing political and public debate worldwide regarding what, if any, action should be taken to reduce or reverse future warming or to adapt to its expected consequences.
From Wikipedia, the free encyclopedia
The average global air temperature near the Earth's surface increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the hundred years ending in 2005. The Intergovernmental Panel on Climate Change (IPCC) concludes "most of the observed increase in globally averaged temperatures since the mid-twentieth century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations" via the greenhouse effect.
Natural phenomena such as solar variation combined with volcanoes probably had a small warming effect from pre-industrial times to 1950 and a small cooling effect from 1950 onward. These basic conclusions have been endorsed by at least thirty scientific societies and academies of science, including all of the national academies of science of the major industrialized countries. While individual scientists have voiced disagreement with some findings of the IPCC, the overwhelming majority of scientists working on climate change agree with the IPCC's main conclusions.
Climate model projections summarized by the IPCC indicate that average global surface temperature will likely rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the twenty-first century. The range of values results from the use of differing scenarios of future greenhouse gas emissions as well as models with differing climate sensitivity. Although most studies focus on the period up to 2100, warming and sea level rise are expected to continue for more than a thousand years even if greenhouse gas levels are stabilized. The delay in reaching equilibrium is a result of the large heat capacity of the oceans.
Increasing global temperature will cause sea level to rise, and is expected to increase the intensity of extreme weather events and to change the amount and pattern of precipitation. Other effects of global warming include changes in agricultural yields, trade routes, glacier retreat, species extinctions and increases in the ranges of disease vectors.
Remaining scientific uncertainties include the amount of warming expected in the future, and how warming and related changes will vary from region to region around the globe. Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions, but there is ongoing political and public debate worldwide regarding what, if any, action should be taken to reduce or reverse future warming or to adapt to its expected consequences.
From Wikipedia, the free encyclopedia
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