weather & climate 2 Flashcards
1
Q
natural cause of climate change
A
- —> variations in solar output
- —> volcanic eruptions
2
Q
variations in solar output
A
sunspots:
- —> cooler regions on sun’s surface
- —> when solar energy is high, more sunspots
- —> areas surrounding the sunspots radiate more energy
- —> this compensates for the lower temp of sunspot areas
3
Q
volcanic eruptions
A
- —> large amounts of CO2, H2O, SO2, dust & ash
- —> SO2 + H2O : sulphur based particles
- —> Dust, ash & sulphur based particles reflect solar energy back into space
- —> global dimming: reduction of sunlight reaching earth
- —> it cools the earth for months/years
4
Q
example of volcanic eruption
A
- —> mount Pinatubo, Philippines
- —> released 17 million tonnes of SO2
- —> formed sulphur based particles
- —> the particles reflected solar energy back into space
- —> lowered temp in northern hemisphere by as much as 0.6C
- —> lowered temp lasted for 2 years
5
Q
why volcanic eruption have few long-term effects
A
- —> temporary global effect will cease once dust and ash settle
- —> 2 years after mount Pinatubo erupted, global climate returned to its original state
- —> volcanic eruptions insignificant compared to human activities
6
Q
what is the greenhouse effect?
A
- —> natural process
- —> essential to life on earth
Shortwave radiation
- —> shortwave radiation from the sun passes through the greenhouse gases found in atmosphere
- —> some shortwave radiation is reflected by the earth and atmosphere
- —> most shortwave radiation is absorbed by earth’s surface which heats up
Longwave radiation
- —> warm surface of earth emits longwave radiation to atmosphere
- —> greenhouse gases absorb longwave radiation
- —> warms the atmosphere
7
Q
what is enhanced greenhouse effect
A
- —> increase in conc of greenhouse gases in atm
- —> leads to rise in global temp
- —> human activity leads to rise
8
Q
what are the anthropogenic (human) factors that cause climate change?
A
U&I BAD Urbanization Industries Burning of fossil fuels Agriculture Deforestation
9
Q
urbanisation
A
—-> population increase
Large no. of fossil fuels burnt for:
- —> household activities (heating, cooling, cooking & lighting)
- —> high transportation
- —> constructing/producing infrastructure
10
Q
industries
A
what is industries:
—-> production of goods & services
what produces emissions:
- —> manufacturing
- —> when goods are produced
processes:
- —> mobile phone: 60 kg of CO2
- —> computer: 275 kg of CO2
where:
- —> North & central America
- —> Europe
- —> Asia
- —> China
- —> India
11
Q
Burning of fossil fuels
A
WHAT
- —> formed from dead organic matter that has decomposed over millions of years
- —> major fossil fuels: oil, coal & natural gas
WHY BURN FOSSILS
- —> produces a large amount of energy important for human activities
- —> produce >80% of global energy
- —> energy used for: industries, transportation & domestic activities
RESULT OF BURNING
- —> fossils have high C content
- —> produce large amounts of CO2 when burnt
- —> highest contributor of greenhouse gases
12
Q
Agriculture
A
WHAT
—-> practice of cultivating land, producing crops and raising livestock
- —> Tractors
- —> run on fossil fuels, which release CO2
- —> Use of inorganic fertilizers
- —> increases nitrous oxide in soil
- —> nitrous oxide released when soil is ploughed or when rain flows through the soil
- —> Organic material
- —> dead leaves
- —> release CH4 methane during decomposition
- —> decomposition rapid as high level of moisture in soil
- —> Cattle farming
- —> release methane as waste gas
13
Q
Deforestation
A
WHAT
—-> loss of forests due to the removal of trees in forested areas
WHY
- —> Trees: wood for products like paper and building materials
- —> Trees removed for mining activities, grazing of animals, planting of crops and construction of infrastructure
IMPACTS
- —> forests absorb tonnes of CO2 via photosynthesis
- —> lesser trees: lesser trees to absorb CO2: increase in CO2 levels
- —> C in soil accumulates through decay of organic matter like dead leaves and animals
- —> deforestation exposes soil to sunlight
- —> this increases soil temp and rate of carbon oxidation
- —> carbon oxidation: C in soil reacts with O2 to produce CO2
14
Q
Deforestation examples
A
- —> btw 2000-2010: 52000 km2 forest lost
- —> South America, Southeast Asia
- —> Australia and Africa
15
Q
impacts of climate change
A
- —> sea level rise
- —> more frequent extreme weather events
- —> spread of infectious insect-borne disease
- —> lengthening growing season
