TOPIC P: IMPACT OF CLIMATE CHANGE Flashcards
What is the carbon cycle?
- Carbon enters the atmosphere as carbon dioxide from respiration and combustion.
- Carbon dioxide is absorbed by producers such as plants to make carbohydrates in photosynthesis.
- Animals feed on the plant passing the carbon compounds along the food chain. Most of the consumed carbon is exhaled as carbon dioxide formed during respiration.
- In the sea, marine animals may convert some of the carbon in their diet to calcium carbonate which is used to make their shells. Over time, the shells of dead orgnanisms collect on the seabed to form limestone, This limestone may eventually become exposed to the air where its weathered and mat be released back into the atmosphere as carbon dioxide.
- Volcanic action may also release carbon dioxide.
What is a carbon sink and what do they do?
Carbon sinks are rainforests and oceans. They accumulate and store carbon containing chemical compounds for an indefinite period. This process is carbon sequestration.
Ho
How does increasing energy usage lead to enhanced greenhouse emissions?
Energy related carbon dioxide and methane emissions via combustion of fossil fuels comes from transportation, industrial, residential and commercial.
Transport:
Gasoline, when combusted in vehicle engines releases Carbon Dioxide as a by-product.
Carbon dioxide emissions primarily involve fossil fuels burnt for road, rail, air and marine transport.
I,R,C
Combustion of fossil fuels to generaye electricity to power homes, busines and industries emit different amounts of carbon dioxide depending on the type of fuel.
Methane is released into the atmosphere during the extraction, storage and transportation of fossil fuels such as oil, coal and gas, as well as from natural gas pipelines.
How does deforestation lead to an enhanced greenhouse effect?
Deforestation refers to practices or processes that convert forested lands for non-forests uses. Rainforests are particularly important as carbon sinks, helping to absorb carbon dioxide into their biomass.
The burning or decomposition of wood releases carbon dioxide.
Trees that once removed carbon dioxide from the atmosphere via photosynthesis are no longer present.
How does increasing consumption of meat lead to enhanced greenhouse effect?
With increased population and prosperity, people consume more meat and dairy each year.
More forests need to be cleared to provide more land for grazing and farming, leading to increased carbon dioxide emissions. Livestock currently use 30% of earth’s land surface.
There is an increase in populations of ruminants, including cows, goats and sheep, These animals produce methane via enteric fermentation in their digestive system, which are released into the atmosphere through belching.
There is also production of livestock manure, which when decomposed under anaerobic conditions releases methane and carbon dioxide.
How does ocean warming lead to the death of coral reefs?
Warmer water temperatures brought on by climate change stress corals.
Both corals and zooxanthellae are very sensitive to changes in temperature.
Photosynthesis in zooxanthellae is disrupted at higher than usual temperatures, and they produce an excess of products that are toxic to themselves. This damages coral metabolism, expelling the zooxanthellae.
Bleached coral can recover if water temperature cools to a favourable condition. Without nutrients provided by their zooxanthellae, corals will eventually die from starvation and disease.
What is the life cycle of Aedes Aegypti mosquito?
Eggs: Anautogenous female mosquitos must blood feed to acquire the protein necessary to develop a batch of eggs. Blood meal digestion is temperature dependent and takes 2-3 days in the tropics and 5-8 days in the temperature
Larva: Larva emerges from egg, only after the water levels rises to cover the egg. The larva go through 4 growth stages known as instars. At the end of each instar, the larva moult, shedding their cuticle to allow for further growth, The larva bevomes a pupa after moulting 4 times.
Larva takes about 4-5 days to develop into a pupa.
Pupa: Pupa do not feed, they just develop until the adult body is formed. Pupa are mobile, responding to light changes and moving with a flip of their tails towards the bottom or protective areas. Pupa takes about 1-2 days to develop into the adult.
Adult: Aedes Ae. only flies a few blocks during its life.
How does rising sea levels affect the environment?
Added water from melting polar ice caps and the thermal expansion of sea water results in rising sea levels.
On coastal areas, shoreline erosion and degradation occurs as waves penetrate further inland. Amplified Storm surges
Permanent inundation of low-lying islands.
Saltwater intrusion into coastal groundwater, increasing salinity of groundwater.
Destruction of important ecosystems like mangroves.
How does organic frozen matter melting impact the environment?
Earth’s soil carbon is stored as frozen organic matter in permafrost. Permafrost can thaw or melt as the ground temperature increases.
Impacts:
Land above permafrost changes shape, can damage buildings and infrastructure.
Bacterial decomposition of the soil accelerates, causing the trapped carbon to be released to the atmosphere in the form of methane.
This process leads to more climate change and is a positive feedback loop when warming causes changes that lead to even more warming.
How does ocean acidification lead to coral reef death?
The ocean is a carbon sink which absorbs a quarter of the human-induced CO2 emissions into the atmosphere every year.
When CO2 dissolves into the ocean, carbonic acid is formed.
At low pH, corals cannot absorb the CaCO3 they need to maintain their skeletons, reefs will dissolve. Coral growth is limited, pre-existing coral skeletons corrode while new ones have slowed growth, making the reefs more vulnerable to erosion.
How does dengue virus develop in humans?
Langerhans cells detect invading pathogen and display dengue viral antigens on their surface.
Langerhans cells then travel to the lymph nodes to activate the immune system.
While the infected Langerhans cells travel to the lymph node, dengue is replicating in the infected Langerhans cells. Mature dengue viruses are released and monocytes and macrophages are targeted and infected by the virus. They travel through the lymphatic and circulatory systems and dengue virus spreads throughout the body. The virus infects more cells.
Results in viriemia, where there is a high level of dengue virus in the bloodstream.
Why has the dengue virus begun to spread outside the tropics?
Dengue is transmitted by Aedes Mosquitoes, which are highly sensitive to environmental conditions. Optimal temperatures for development, longevity and fecundity are between 22-32C.
It will result in faster growth rate and development, increased activity of egg-laying mosquitoes, increased egg-laying and more eggs per female, and reduces the intrinsic incubation period for the dengue virus.
