02 climate and weather (causes)

Question 1

variation in solar output

Answer 1

a peak in the number of sunspots coincided with high solar activity and global temperatures increased in 2000.

Question 2

volcanic eruptions

Answer 2

the eruption of mount pinatubo in 1991 released 17 million tonnes of sulfur dioxide into the atmosphere. this formed sulfur-based particles that spread around the world and hence reflected solar energy back into space. thus, global temperatures dropped by 0.6oC and resulted in cooling instead of warming. this lasted up to two years in some locations. despite this short-lived cooling, eruptions release large amounts of greenhouse gases such as carbon dioxide and could cause global warming to escalate instead. since the 1980s, human activities have caused emissions of more than one hundred times of these volcanic eruptions.

KIV

Question 3

deforestation

Answer 3

worldwide, trees absorb around 2.4 million tonnes of co2 with the amazon basin responsible for about 1/4 of that. with deforestation, it now absorbs 30% less than in the 1990s.

Question 4

carbon oxidation

Answer 4

according to the university of maryland, usa, the world lost 11.1 million hectares of forests which emitted 2.5 gigatonnes of carbon dioxide, a volume equivalent to india’s emissions in 2021. this area of forests could have absorbed around 1.34 gigatonnes of carbon dioxide which would have reduced carbon dioxide levels in the atmosphere drastically and could have an impact on global warming.

Question 5

cattle ranching

Answer 5

in argentina, there are around 55 million cows grazing its grasslands. each cow produces around 1000 to 8000 litres a day. in a day alone, around 2.2 gigatonnes of methane would be released.

Question 6

rice cultivation

Answer 6

in 2019, land ploughing due to tractors that run on fossil fuels amount to 1 hundred thousand tonnes of carbon dioxide alone.

methane absorbs 21 times more heat than carbon dioxide, making it a more potent greenhouse gas.

Question 7

urbanisation

Answer 7

in 2019, china had a total emission of 36.3 billion tonnes of carbon dioxide alone. before urbanisation in the 1950s, china had a mere 68 tonnes of carbon dioxide emissions.

Question 8

industrialisation

Answer 8

a handphone produces around 60 kg of carbon dioxide and china produces around 1 billion smartphones a year. this amounts to 60 million tonnes of carbon dioxide emitted alone.