GLOBAL WARMING CASE STUDY
what is global warming?
definition: Global warming is the long-term heating of Earth’s surface observed since the pre-industrial period (between 1850 and 1900) due to human activities, primarily fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth’s atmosphere.
this is different from the greenhouse effect. the greenhouse effect is actually a natural process that facilitates a life sustaining temp of 150C.
the gasses that are responsible for trapping heat are: water vapour, carbon dioxide, and methane. all of which are natural.
about 30% of the suns radiation is reflected by the ground, atmosphere and clouds. the long wave radiation is emitted and reabsorbed by the greenhouse gasses and without them the atmosphere would be too hot in some places and to cold in other making earth uninhabitable.
what are the major greenhouse gasses and what are their sources?
carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, chlorofluorocarbons, and water vapour. are the main types of manmade greenhouse gasses.
carbon dioxide=
released through natural processes such as volcanic eruptions. and through human activities such as burning fossil fuels and deforestation.
methane =
this comes from natural processes such as plan matter decaying in wetlands and from animals such as cows. the human processes are large scale pastoral farming, land fills and rice farms.
leaks from fossil fuel production, transportation and natural gas use is another huge source of methane as it is about 70%-90% methane.
nitrous oxide=
produced by farming and is produced during organic and commercial fertiliser use
this also comes from burning fossil fuels and vegetation.
CFC’s=
these are entirely produced through industrial methods.
they were used in refrigerators, solvents and aerosols.
water vapour =
water vapour is the most abundant gas in the atmosphere this is due to the global warming heating up oceans increasing the amount of vapour in the air.
what are the effects of global warming?
Evidence for global warming
• 10–25cm rise in sea levels during the 20th century.
• 0.3–0.6°C rise in global temperatures since late 19th century.
• 0.2–0.3°C rise in past 40 years.
• Diurnal temperature range has reduced over 40% of the land’s surface, due to increased
insolation caused by increased cloud cover.
• NASA has measured shrinkage of Arctic pack ice at 2.9% per decade. It has thinned from 3.1m to 1.8m in a decade.
• A 2.5°C rise in temperature since the 1940s has lengthened the annual melt season in Antarctica by 2–3 weeks.
predictions
• Average global temperature rise of 1.5–4°C over the next century.
• By 2050, carbon dioxide levels will have doubled from pre-industrial times.
• 50 cm rise in average sea levels by 2100.
• Extra 50–80 million cases of malaria/year worldwide.
• World vegetation zones will change, affecting agriculture.African yields of millet, the main staple food, will decline by 63–79%, leading to famine.
• Millions of people will be displaced by coastal flooding, erosion and drought. Major coastal cities, including New York and London, will be at higher risk from flooding.
• Rainfall will become more unpredictable and more uneven.
• Britain may receive 20% more rain, but also higher sun hours as the weather patterns change to give more downpours. 2000 miles of Britain’s rivers will be become flood risk areas.
• More severe weather events and extremes of climate will occur, as there will be more energy in the atmosphere, creating more violent convection, winds and pressure differences.
examples of these effects taking place.
the recent floods in Pakistan due to heavier than normal monsoon rains. causing detrimental effects to the farm lands, infrastructure and homes of all these people.
intense heatwaves in the UK
intense typhoons such as Haiyan in the Philippines (2013)
significantly less snow coverage in places such a the Himalayas, Alaska and other areas in Europe.
the great barrier reef experiencing the worse coral bleaching and damage in decades.