Case studies - Climate Change Flashcards
(19 cards)
Global dimming (natural varian\bility of climate)
Volcanic eruption of Mount Pinatubo in 1991 led to a drop in average global temperature of about 0.6C over 15 months after
Burning of fossil fuels
Use of fossil fuels increased steeply since the start of the industrial revolution in the 1880s contributing to more than 35 billion tonnes of carbon dioxide emissions per year
Land clearance
Globally tropical deforestation contributes to about 20% of annual greenhouse gas emissions
Agriculture
In paddy rice fields decomposition is rapid due to the high amount of moisture in the soil which contributes to 5 - 20% of total methane emissions
In emerging economies such as China and India, there will be higher demand for rice as their disposable incomes increases allowing them to by more food than needed. The methane gas forms in water loggeD soils as a by product of anaerobic decomposition of matter as it bubbles through the surface and escapes into the atmosphere contributing to greenhouse emissions. Fertilisers also releases nitrous oxide into the atmosphere.
The increased demand for meta would lead to the clearance of more land to make space for farms to breed cows to grow crops and rear more animals to meet the demands. The cows burps and farts contains methane and the clearance of land is required
Industries
It is estimated that they contributed about 43% of greenhouse gasses annually
Urbanisation
Cities consume about 78% of the worlds energy and contribute significantly to the emission of greenhouse gases
Increases precipitation and occurrences of excessive rainfall (wetter regions)
Parts of Hereford, England were continuously flooded since October 2020 (autumn-winter).
- Affected burrowing animals due to limited access to dry land, disrupted hibernation cycle. Dangerous for the animals.
- Suffocated, drowned and weakened plants and other insects (disrupt food web)
- Waters polluted with sediments, run-off and pollutants. Animals have no source of clean water. Water visibility decreased, animals cannot hunt.
Decreased precipitation and occurrences of excessive draught (drier regions)
Puerto Rico drought, 2015
- Reduced water availability in streams.
- Reduced food and water sources led to migration of bird populations, and overall widespread stress on organisms.
- Migration of certain species led to an imbalanced ecosystem and food web
- The trees in the ecosystem experienced leaf loss and reduced growth, impacting ecosystem balance
Increase in ocean surface temperatures
Since the industrial era began in around 1850, the global average sea-surface temperature has increased by an average of 0.68-1.01°C
Impact on aquatic ecosystem
Great Barrier Reef, Australia. Sea levels there have risen by 3 mm per year since 1991 till now.
- Coral bleaching: 73% of surveyed reefs in the Great Barrier Reef Marine Park have prevalent bleaching. (Co2, temp, salinity, pH, levels all affected). Corals are unable to migrate to habitats with more favourable conditions as well.
- Since the industrial revolution in the 1800s, ocean acidity globally increased by 25%
- Increased production of carbonic acid in the ocean affects organisms such as shellfish or corals that use calcium carbonate to form their skeletons and shells, which is dissolved by carbonic acid.
- Slower ocean circulation causes waters to be unable to rise to the ocean’s surface. The plankton’s food is unable to be carried to them. Phytoplankton levels in the North Atlantic have dropped by 10% since the 1800s
- Land at Great Barrier reef is low-lying, there are increased rates of erosion and land inundation. exacerbates beach erosion and floods nests.
Impact on terrestrial ecosystems
Research by OSC Viterbi shows a predicted decrease in species diversity from 2010-2070 in North America, as well as a visible shift of species Northward.
- Amazon Rainforest, South America from early 2000s to now
Warming at a rate of 0.27 degrees celsius per decade. Slowly shifting towards a dry savannah environment. 19% of the original forest was destroyed by deforestation. Loss of habitat, cut off migration routes. Pollution associated with infrastructure expansion affects organisms, contaminated food/water
Many species are becoming endangered due to loss of habitat, dwindling supplies of food.
- 170 species of birds tracked in North ameri ca have expanded their range northwards by 50km on average over the past 4 decades
Impact on islands
Kiribati, an increase in global temperature causes Kiribati’s sea level to rise by 50 to 100 centimetres. Kiribati is vulnerable to rising sea levels caused by global warming, and is likely to be submerged. two of its uninhabited islands, Abanuea and Tebua Tarawa have already submerged.
Survey conducted reveals 70% of households in Kiribati and Tuvalu would migrate if climate change worsened
Floods
- Bangladesh is a densely populated low-lying country with many people living near coastal areas and it has a monsoon climate hence it experiences seasonal flooding. It receives meltwater from the Himalayan ice caps and glaciers and is vulnerable to coastal flooding due to the rise of sea levels. In 2020, they experienced its worst monsoon due to intense rainfall causing about an estimated 260 people to die and 1.3 billion homes were destroyed. The damage of agricultural crops estimated was the value of millions of dollars which is substantial for them as they are a developing country
- Madagascar Floods, 2022:
Experienced multiple tropical storms, including Tropical Storm Ana and Cyclone Batsirai.
Climate change intensified rainfall, increasing storm severity.
Resulted in deaths, injuries, and extensive infrastructure damage, highlighting the vulnerability of low-income nations to climate-related disasters. - A real-life example of the issues caused by melting glaciers is the Himalayan region in South Asia, particularly in Nepal, India, and Bangladesh. The melting of Himalayan glaciers has initially increased freshwater availability, benefiting agriculture and water supply. However, this has led to long-term problems, including flooding, as rivers overflow with the extra water from glaciers combined with heavy rains. For example, the Koshi River regularly floods, displacing people and destroying crops, which worsens food insecurity. Rising sea levels, influenced by glacier melt, also cause saltwater intrusion into freshwater sources, particularly in low-lying areas like the Sundarbans in India and Bangladesh, damaging agriculture and making drinking water undrinkable.
- Increased precipitation and flooding → During Hurricane Harvey (2017) in the U.S., intense rainfall caused severe flooding, leading to surface runoff that contaminated water sources with sewage, chemicals, and agricultural waste. The floodwaters carried industrial pollutants into rivers and reservoirs, increasing exposure to waterborne diseases.
extreme drier weathers (drought, heatwaves and wildfires)
- 2020 Thailand drought
Lack of rainfall and shorter monsoon season cause reservoirs/water bodies to dry up
Drought severely affected Thailand as its agricultural sector uses 70% of the nation’s water supply
The economic livelihoods of farmers greatly impacted - The 2018-2019 drought in Afghanistan affected more than two-thirds of the country. Over ten million people were affected due to a lack of food, and many were displaced. Up to 85% of country’s food comes from irrigated farming, so they experienced significant food insecurity during this time. Over 14 million people were projected to experience food shortage in 2020.
- 2023 heat wave in europe where 70000 people died from the heat wave which lasted for 2 weeks and the harvest for agricultural crops such as wheat was affected as many crops died increasing the price of bread significantly causing food to become less affordable
- 2019 - 2020 wildfires in australia which was widespread affecting the whole continent. The air quality was hazardous and was a human health risk as the air quality measured 11 times greater than what is set as a hazardous level and in total 34 people died and thousands of buildings were burnt down leaving many homeless. The fires are difficult to control and put down due to the hot and dry conditions induced by climate change
Severe and frequent cyclons
- Over 4 weeks from october to novemner 2020 the philipines was hit by 6 tropical cyclones and the strongest typhoon that his them was typhoon goni which brought about strong destructive winds and high rainfall leading to the loss of lives and massive destruction of properties, evacuation of nearly a million people, estimated damage of crops worth 36 million dollars and the power supplies were cut. As a developing country the country’s infrastructure was not able to cope with the severe flooding and the communities did not have time to recover before another cyclone hit.
vector-borne diseases
Before 2018 mosquitos were non-existent in the mountain regions of Bhutan as they are usually too cold to breed however in 2019 they suffered the country’s first national dengue epidemic where many parts of the country reported cases of the virus
rising sea levels
Kiribati:
The country is highly vulnerable to rising sea levels and saltwater intrusion, which impact freshwater supplies and create unsuitable soil conditions for growing crops, threatening food security.
Frequent natural disasters threaten infrastructure and water resources.
Hargeisa, Somalia depended on its agriculture as a large source of income (⅗ of income), however, due to the increased salinity of fertile soil, they are unable to make a profit → economy is affected
poverty
the spread of malaria in the highlands of Malawi occured due to the increase in temperature. They suffer from poverty and lack health resources to get treated hence malaria was the leading cause of death in pregnant women and children
lack of access pipes water
Dar Es Salaam, Tanzania. floods in the city resulted in the contamination of wells leading to high incidences of cholera and there were more than 5000 cases from 2015 -2016
