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Explain what causes global warming and discuss some of its possible effects.?
- Thread starter Vongda
- Start date
M
marjr
Guest
Global warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-20th century and its projected continuation. Global surface temperature increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the last century.[1][A] The Intergovernmental Panel on Climate Change (IPCC) concludes that increasing greenhouse gas concentrations resulting from human activity such as fossil fuel burning and deforestation are responsible for most of the observed temperature increase since the middle of the 20th century.[1] The IPCC also concludes that natural phenomena such as solar variation and volcanoes produced most of the warming from pre-industrial times to 1950 and had a small cooling effect afterward
The effects of global warming are of concern both for the environment and human life. Scenarios studied by the Intergovernmental Panel on Climate Change (IPCC) predict that global warming will continue and get worse much faster than was expected even in their last report. Research by NOAA indicate that the effects of global warming are already irreversible.[2] The IPCC reports attribute many specific natural phenomena to human causes. The expected long range effects of recent climate change may already be observed. Rising sea levels, glacier retreat, Arctic shrinkage, and altered patterns of agriculture are cited as direct consequences of human activities. Predictions for secondary and regional effects include extreme weather events, an expansion of tropical diseases, changes in the timing of seasonal patterns in ecosystems, and drastic economic impact. Concerns have led to political activism advocating proposals to mitigate, or adapt to it. Geoengineering is a further potential response, which could potentially reverse some effects that may otherwise be irreversible.[3]
It is notable that many of the effects of global warming are non-linear in nature, with potential for dramatic positive feedback effects. This means that the climate may enter a critical state where small changes can trigger runaway or abrupt climate change. Geoengineering has been suggested as a means of interrupting or reversing these effects.[4] A notable example of a 'runaway' effect is the release of methane from clathrates (known as the clathrate gun effect).[
POSSIBLE EFFECTS:
Effects on weather
Global warming may be responsible in part for some trends in natural disasters such as extreme weather.Increasing temperature is likely to lead to increasing precipitation [11][12] but the effects on storms are less clear. Extratropical storms partly depend on the temperature gradient, which is predicted to weaken in the northern hemisphere as the polar region warms more than the rest of the hemisphere.[13]
Glacier retreat and disappearance
Main article: Retreat of glaciers since 1850
A map of the change in thickness of mountain glaciers since 1970. Thinning in orange and red, thickening in blue.
Lewis Glacier, North Cascades, WA USA is one of five glaciers in the area that melted awayIn historic times, glaciers grew during a cool period from about 1550 to 1850 known as the Little Ice Age. Subsequently, until about 1940, glaciers around the world retreated as the climate warmed. Glacier retreat declined and reversed in many cases from 1950 to 1980 as a slight global cooling occurred. Since 1980, glacier retreat has become increasingly rapid and ubiquitous, and has threatened the existence of many of the glaciers of the world. This process has increased markedly since 1995.
Oceans
The role of the oceans in global warming is a complex one. The oceans serve as a sink for carbon dioxide, taking up much that would otherwise remain in the atmosphere, but increased levels of CO2 have led to ocean acidification. Furthermore, as the temperature of the oceans increases, they become less able to absorb excess CO2. Global warming is projected to have a number of effects on the oceans. Ongoing effects include rising sea levels due to thermal expansion and melting of glaciers and ice sheets, and warming of the ocean surface, leading to increased temperature stratification. Other possible effects include large-scale changes in ocean circulation.
Sea level rise
Temperature rise
From 1961 to 2003, the global ocean temperature has risen by 0.10 °C from the surface to a depth of 700 m. There is variability both year-to-year and over longer time scales, with global ocean heat content observations showing high rates of warming for 1991 to 2003, but some cooling from 2003 to 2007.[61] The temperature of the Antarctic Southern Ocean rose by 0.17 °C (0.31 °F) between the 1950s and the 1980s, nearly twice the rate for the world's oceans as a whole [69]. As well as having effects on ecosystems (e.g. by melting sea ice, affecting algae that grow on its underside), warming reduces the ocean's ability to absorb CO2
Temperature rise
Acidification
Oxygen depletion
The amount of oxygen dissolved in the oceans may decline
The effects of global warming are of concern both for the environment and human life. Scenarios studied by the Intergovernmental Panel on Climate Change (IPCC) predict that global warming will continue and get worse much faster than was expected even in their last report. Research by NOAA indicate that the effects of global warming are already irreversible.[2] The IPCC reports attribute many specific natural phenomena to human causes. The expected long range effects of recent climate change may already be observed. Rising sea levels, glacier retreat, Arctic shrinkage, and altered patterns of agriculture are cited as direct consequences of human activities. Predictions for secondary and regional effects include extreme weather events, an expansion of tropical diseases, changes in the timing of seasonal patterns in ecosystems, and drastic economic impact. Concerns have led to political activism advocating proposals to mitigate, or adapt to it. Geoengineering is a further potential response, which could potentially reverse some effects that may otherwise be irreversible.[3]
It is notable that many of the effects of global warming are non-linear in nature, with potential for dramatic positive feedback effects. This means that the climate may enter a critical state where small changes can trigger runaway or abrupt climate change. Geoengineering has been suggested as a means of interrupting or reversing these effects.[4] A notable example of a 'runaway' effect is the release of methane from clathrates (known as the clathrate gun effect).[
POSSIBLE EFFECTS:
Effects on weather
Global warming may be responsible in part for some trends in natural disasters such as extreme weather.Increasing temperature is likely to lead to increasing precipitation [11][12] but the effects on storms are less clear. Extratropical storms partly depend on the temperature gradient, which is predicted to weaken in the northern hemisphere as the polar region warms more than the rest of the hemisphere.[13]
Glacier retreat and disappearance
Main article: Retreat of glaciers since 1850
A map of the change in thickness of mountain glaciers since 1970. Thinning in orange and red, thickening in blue.
Lewis Glacier, North Cascades, WA USA is one of five glaciers in the area that melted awayIn historic times, glaciers grew during a cool period from about 1550 to 1850 known as the Little Ice Age. Subsequently, until about 1940, glaciers around the world retreated as the climate warmed. Glacier retreat declined and reversed in many cases from 1950 to 1980 as a slight global cooling occurred. Since 1980, glacier retreat has become increasingly rapid and ubiquitous, and has threatened the existence of many of the glaciers of the world. This process has increased markedly since 1995.
Oceans
The role of the oceans in global warming is a complex one. The oceans serve as a sink for carbon dioxide, taking up much that would otherwise remain in the atmosphere, but increased levels of CO2 have led to ocean acidification. Furthermore, as the temperature of the oceans increases, they become less able to absorb excess CO2. Global warming is projected to have a number of effects on the oceans. Ongoing effects include rising sea levels due to thermal expansion and melting of glaciers and ice sheets, and warming of the ocean surface, leading to increased temperature stratification. Other possible effects include large-scale changes in ocean circulation.
Sea level rise
Temperature rise
From 1961 to 2003, the global ocean temperature has risen by 0.10 °C from the surface to a depth of 700 m. There is variability both year-to-year and over longer time scales, with global ocean heat content observations showing high rates of warming for 1991 to 2003, but some cooling from 2003 to 2007.[61] The temperature of the Antarctic Southern Ocean rose by 0.17 °C (0.31 °F) between the 1950s and the 1980s, nearly twice the rate for the world's oceans as a whole [69]. As well as having effects on ecosystems (e.g. by melting sea ice, affecting algae that grow on its underside), warming reduces the ocean's ability to absorb CO2
Temperature rise
Acidification
Oxygen depletion
The amount of oxygen dissolved in the oceans may decline
Ravindra P
New member
Main reason for global warming is the excessive green house effect. What is Global warming? How it has happened? The problem is that human activity is making the blanket of gases ‘thicker’ which enhances the greenhouse effect. The research shows that the main culprit was CO2 emissions, produced by the burning of fossil fuels (coal, gas, and oil) in factories and power stations, and cars. When we burn coal, oil, and natural gas, we spread huge amounts of CO2 into the Earth’s atmosphere filling it up with large amounts of greenhouse gases, much much more than what is okay. Our other basic activities, such as raising cattle and planting rice, emit methane, nitrous oxide, and other greenhouse gases. Other reasons are pollution by heavy vehicles which release heat along with harmful gases. Wars and bomb explosions also are other causes. This further enhances the warming within atmosphere. But they are minor compared to deforestation.
When we destroy forests, the carbon stored in the trees escapes to the atmosphere, in the forms of carbon dioxide, carbon monoxide or carbon soot. If emissions continue to grow at current rates, it is almost certain that atmospheric levels of CO2 will double from pre-industrial levels during the 21st century. If no steps are taken to slow down greenhouse gas emissions, it is quite possible that levels will triple by the year 2100. While carbon dioxide concentration in the atmosphere just before the industrial revolution (1750 – 1800) was about 280 ppm (parts per million), has presently crossed 400 ppm. Beyond 450 ppm means serious ecological and economical damage according to scientists. Global warming is already altering the habits, migration and breeding of animals, which eventually affect humans. Due to global warming, the level of the sea is expected to increase by 1 to 1.5 meters during next 4 to 5 years as per opinion of the scientists. Two islands, Tebua Tarawa and Abanuea of Kiribati which have already sunk beneath the waves during 1999 were the first victims of rising seas brought about by Global warming. There are many other effects being seen as direct results of global warming including climatic changes.
When we destroy forests, the carbon stored in the trees escapes to the atmosphere, in the forms of carbon dioxide, carbon monoxide or carbon soot. If emissions continue to grow at current rates, it is almost certain that atmospheric levels of CO2 will double from pre-industrial levels during the 21st century. If no steps are taken to slow down greenhouse gas emissions, it is quite possible that levels will triple by the year 2100. While carbon dioxide concentration in the atmosphere just before the industrial revolution (1750 – 1800) was about 280 ppm (parts per million), has presently crossed 400 ppm. Beyond 450 ppm means serious ecological and economical damage according to scientists. Global warming is already altering the habits, migration and breeding of animals, which eventually affect humans. Due to global warming, the level of the sea is expected to increase by 1 to 1.5 meters during next 4 to 5 years as per opinion of the scientists. Two islands, Tebua Tarawa and Abanuea of Kiribati which have already sunk beneath the waves during 1999 were the first victims of rising seas brought about by Global warming. There are many other effects being seen as direct results of global warming including climatic changes.