climate change Flashcards
(37 cards)
what are greenhouse gases and some eg
a gas that both absorbs and emits radiation in the infrared range. CO2 and methane.
list all anthropogenic activities that contribute to global GHG emissions
- burning of fossil fuels to provide energy –> coal is the most carbon intensive fossil fuel, it results in more CO2 emission
- transportation –> combustion of gasoline and diesel
- industrial purposes –> increased demand for energy comes from worldwide economic growth and development. non-combustion processes include semiconductor manfacture and petrochemical production
- clearing of forests –> clearing of forests and mangroves and draining of waterlogged peatlands decrease amt of CO2 sinks available. the subsequent decomposition and burning of biomass releases more GHGs. –> conversion of forests and grasslands to cropland and pasture.
- Food choices –> the growth in per capita meat consumption is strongly linked to increasing levels of income in many countries in the world. Coupled with global human population growth, global meat consumption also increased accordingly. –> industrial style agriculture had made meat more affordable to the masses.
State 4 effects of GHG emissions on climate change –> related to environment
- melting of ice sheets, polar ice caps and glaciers resulting in rise of sea levels.
2.heatwaves and heavy rainfall - stress on freshwater supplies.
- release of GHG in frozen organic matter.
how does melting of ice sheets, polar ice caps and glaciers result in sea level rise
thermal expansion of seawater –> ocean temp rises, particles move more vigorously, causes expansion of water, increasing overall vol of ocean, rise in average sea levels.
melting of polar ice caps –> addition of water to the oceans.
comparison of melting of land ice vs sea ice
melting of sea ice does not result in any increase in sea level, as sea ice already displaces water. Melting of sea ice affects marine animals as they lose access to feeding grounds. There is loss of albedo. –> as melting occurs, more of the less-reflective water surface is exposed and absorb more sunlight –> air becomes warmer and more ice melts
impact of heatwaves and heavy rainfall on ecosystem
rainfall increases in tropics –> produces more pollution such as erosion and sedimentation due to run-off and water-borne diseases and lower water quality likely to increase, and increased risk of flooding, and eutrophification. Number of frost days is expected to decrease, increasing growing season and increase food production.
rainfall decrease in already dry subtropics –> increase drought, cause more heat-related deaths
why is scarcity of freshwater is expected to increase
- groundwater depletion that is affected by change in precipitation pattern –> affects replenishment of groundwater negatively.
- decline in water quality
-areas with increased precipitation: corresponding increase in runoff, larger levels of sediment and contaminants into waterways and drinking reservoirs
-areas with drought: groundwater reserves may be depleted and residual water is often of inferior quality.
-increase in temp –> bloom in microbial population, reduce amt of dissolved O2 in water
-salination in water supplies by coast side.
what is permafrost
a layer of soil or rock that is frozen all year round. Stores an immense amount of carbon and methane
Impact of thawing of permafrost
allow organic matter within the permafrost to decompose, releasing carbon into atmosphere at a faster rate.
Release of methane and increased microbial synthesis of methane.
carbon fixation
Describe physiological characteristics of plants in dry environments
Varying their methods of carbon fixation:
in C4 plants, carbon fixation and Calvin cycle take place in different cells. CO2 is converted to a 4C compound by an enzyme that does not bind to O2. 4C compound is sequestered to a deeper tissue layer where less O2 is present. CO2 is then released and enter the Calvin cycle without competition from O2.
in CAM plants, carbon fixation occurs at night. CO2 is converted to 4C compound which release CO2 for Calvin cycle in the day. This allows stomata to remain close in the day and open at night.
observable features
Describe morphological characteristics of leaves that help to reduce loss of water
- leaf has small surface area to volume ratio.
- thick waxy cuticle and epidermis
- stomata only present on bottom surface of leaf.
- sunken stomata where stomata are found in grooves and often surrounded by hair. Creates a region of high humidity at stomata opening and reduce likelihood of evaporation and water loss through transpiration
state effect on physiological and morphological changes on plants by droughts and high temperatures (water availability is limited)
-reduction of water content and turgor, and cell expansion slow down or ceases.
-alteration in level of photosynthetic pigment
-rapid decrease in amount of RuBisCO and lower amt of carbon fixation
-increased ratio of roots to shoots.
-stomatal closure
-decrease in no. of stomata to reduce transpiration.
–> plant growth is retarded and many plants dehydrate and die under prolonged conditions.
think about pollen
how does global warming affect reproduction of plants
reduce pollen viability.
disrupts flowering process and affects seed production in plants
talk about ratio
how does global warming affect body size of animals
larger surface area to volume ratio of smaller body sizes serve as efficient heat dissipaters in warm climates.
smaller surface area to volume ratio of larger body sizes may help in heat conservation in cold climates
how does change in temperature affect insect metabolism
in ectotherms, rates of both somatic growth and ontogenetic development increase with increasing temperature, time to maturity is shorter at higher temperatures.
majority of ectotherms grow slower but mature at a larger body size in colder environments. Cold environments allow ectotherms to reach a relatively large body size by prolonging growth and delaying production.
what is thermal safety margin
the difference between an organism’s thermal optimum and its current climate temperature
how are insects with different thermal safety margins (tropic vs temperate) affected by climate change
insects in tropic environments: they have small thermal safety margins, even small amounts of warming will likely decrease performance and approach near-lethal temperatures much faster. Many species have small dispersal ranges that increase their risk of extinction through small changes in habitat or environment
insects in temperate environments:
have large thermal safety margins –> broader thermal tolerance. warming may enhance fitness as it causes initial increases in population growth rates and performance. In warmer winters, insects will not all die out. When spring starts earlier, these insects emerge even earlier and can persist in the environment even longer.
how does timings of seasonal life cycle events change with climate change. state one example as well
global warming confuses these signals to alter life cycle and seasonal events, leading to mismatches of timing of migration, breeding and food availability leading to species being out of sync with other species or other important natural events in their ecosystem.
possible examples : - marmots ending their hibernations about three weeks earlier than they did 30 years ago.
-birds are migrating and arriving at their nesting grounds earlier.
effect of climate change on plant distribution and animal migration
as global temp rises, both animal and plant populations are projected to gradually shift upwards to higher elevations and towards northern latitudes where temp are cooler in order to stay within their ideal range of environmental conditions. Compared to animals, plants are more sedentary and may be in greater risk of being affected by changes in climatic condition. The rate of climate change is likely to exceed the migration rates of most plant species.
Being trapped at the top, alpine wildlife is vulnerable to several damaging effects –> vegetation changes, invasion of new predators and pests, reduced winter snowpack and increases in extreme weather events.
Describe impact of temperature changes on distribution of insects
with the warmer climate, many species including insects would migrate northwards or expand their range to remain within their temperature tolerance ranges.
Using the examples of dengue and malaria carriers, Aedes Aegypti and Anopheles mosquitoes, how has global warming affected their spread
they have expanded their ranges towards the northern latitudes and those diseases may become increasingly common in more northerly regions. increased temp and precipitation can increase abundance of mosquitoes and result in faster disease transmission.
Aedes Aegypti and Anopheles mosquito –> lives and breeds in moist tropical regions, thrives in regions with warm temp, humid conditions and high rainfall. –> global warming leads to duration for development from first install to emergence is shorter and rate of enzyme-catalysed reactions increases and there is decreased length of reproductive cycles. global warming could result in more rainfall in certain areas and create more pools of stagnant water for mosquito breeding. Hotter months leads to increased incidence of dengue fever in summer. Results in temperate regions becoming warmer and conditions are more suited for survival of Aedes mozzies and move to higher latitude and expand distribution and higher altitudes become warmer and allow for colonisation of mozzies higher up mountains.
define biodiversity
the variety of plant and animal life in a particular habitat
what are some problems that migrating organism may face
-they may need to compete with other native species for food and other sources
-may be new predators to deal with and may not be able to deal with if not properly adapted.
- possible exposure to new forms of disease may inhibit effectiveness of their migration
- may put into competition with other species over food and other resources and and cause changes to the food web that result in ecological disruptions as predators are separated from prey.
Describe the whole process of how global warming result in death of coral reefs.
Corals have a calcium carbonate exoskeleton that helps to build up the reef. Zooxanthallae are symbiotic with corals as they photosynthesise and produce food for corals. Algae absorb light energy and protect the corals from harmful effects of sunlight . Nitrogenous waste from corals serve as nutrients for algae. Mutualistic relationships it is beneficial to both parties. Extended periods of elevated temperatures cause zooxanthallae to leave the corals –> coral bleaching. Acidification of the ocean due to increased CO2 emission decreases calcification rates of corals and growth is reduced. Over-fishing of herbivorous fish meant that corals are under increased threat from the macro algae. The loss of coral reefs reduces habitats for many other marine organisms and disrupt the ecosystem.
