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 (man-made) greenhouse gas concentrations" via an enhanced 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.
link : http://en.wikipedia.org/wiki/Global_warming
The Small Topic
Deforestation
Deforestation is the conversion of forested areas to non-forest land for use such as arable land, pasture, urban use, logged area, or wasteland. Generally, the removal or destruction of significant areas of forest cover has resulted in a degraded environment with reduced biodiversity. In many countries, massive deforestation is ongoing and is shaping climate and geography. Deforestation results from removal of trees without sufficient reforestation, and results in declines in habitat and biodiversity, wood for fuel and industrial use, and quality of life.
Many tropical countries, including Indonesia, Thailand, Malaysia, Bangladesh, China, Sri Lanka, Laos, Nigeria, Liberia, Guinea, Ghana and the Cote d'lvoire have lost large areas of their rainforest. 90% of the forests of the Philippine archipelago have been cut. In 1960 Central America still had 4/5 of its original forest; now it is left with only 2/5. Madagascar has lost 95% of its rainforests. Brazil has lost 90-95% of its Mata Atlântica forest. Half of the Brazilian state of Rondonia's 24.3 million hectares have been destroyed or severely degraded in recent years. As of 2007, less than 1% of Haiti's forests remain, causing many to call Haiti a Caribbean desert. Between 1990 and 2005, Nigeria lost a staggering 79% of its old-growth forests. Several countries, notably the Philippines, Thailand and India have declared their deforestation a national emergency.
Link : http://en.wikipedia.org/wiki/Deforestation
Effect from Deforestation
Deforestation is often cited as one of the major causes of the enhanced greenhouse effect. According to the Intergovernmental Panel on Climate Change deforestation, mainly in tropical areas, account for up to one-third of total anthropogenic carbon dioxide emissions. Trees and other plants remove carbon (in the form of carbon dioxide) from the atmosphere during the process of photosynthesis. Both the decay and burning of wood releases much of this stored carbon back to the atmosphere. Deforestation also causes carbon stores held in soil to be released. Forests are stores of carbon and can be either sinks or sources depending upon environmental circumstances. Mature forests can be net sinks of carbon dioxide (see Carbon dioxide sink and Carbon cycle).
The water cycle is also affected by deforestation. Trees extract groundwater through their roots and release it into the atmosphere. When part of a forest is removed, the region cannot hold as much water and can result in a much drier climate.
Link : http://en.wikipedia.org/wiki/Deforestation#Atmospheric_pollution
My Summary
Deforestation --> Greenhouse Effect --> Climate Change --> Global Warming
No comments:
Post a Comment