climate change

• weather vs climate


  weather: short-term condition of atmosphere

  climate: how atmosphere behaves over a long period of time
• climate change


  change in LT average daily weather in a region
• GHG


  a gas that both absorbs and emits radiation in infrared range. a gas that traps radiation in the form of heat, caausing a warming effect
• global warming


  A progressive increase in global temperatures. Either through natural reasons or human activity caused by greenhouse gas emissions.
• how do GHGs cause GW

  GHG allow short-wave radiation from the sun to pass through to heat the Earth’s surface and lower atmosphere;The heated surfaces radiate out-going long-wave radiation which is absorbed and re-emitted by the GHGs back to the Earth’s surface;Increased concentration of GHGs leads to increased trapping of radiation causing more warming
• Positive feedback mechanisms is where initial change results in further change of same factor
• is water vapour a concern

  yes and no

  • no: stays in atm for shorter period of time
  • yes: amplify effects of other GHG, warmer air can hold more water vapour
• peatlands


  wetlands with thick waterlogged soil layer made up of dead and decaying plant material

  • most efficient C sink
  • drained for agriculture
• causes of rising sea levels

  GW caused thermal expansion of seawater & melting of land ice
• melting of sea ice does not affect sea levels as sea ice already displaces water BUT affects marine animals (loss of feeding grounds)
• melting of sea ice -> loss of albedo, more of less-reflective water surface exposed, more sunlight absorbed, more ice melting (POSITIVE FEEDBACK)
• when precipitation increases, likely to increase in tropics and decrease in dry subtopics
• permafrost


  layer of soil or rock that is frozen all year round. when thawed, releases carbon and methane (POSITIVE FEEDBACK)
• plants reponse to water stress (photosynthetic rate decrease, plant growth retarded. if prolonged, dehydrate and die)

  • close stomata and decrease stomata density to reduce transpiration
  • increase roots to shoots ratio
  • decrease in amount of RuBisCO, lower C fixation
• adaptations of plants to reduce water loss

  • leaf has small SA:V ratio (cactus)
  • thick waxy cuticle and epidermis
  • stomata only on bottom surface of leaf
  • sunken stomata: stomata found in grooves and surrounded by hair, creating region of high humidity at stomata, reducing likelihood of evap and transpiration
• GW affects plant reproduction

  reduce pollen viability, disrupts flowering process
• warmer T smaller bodies

  large SA:V of smaller bodies dissipate heat
• higher T, shorter time to maturity. faster rate of enzyme-catalysed biochemical reactions
• insects in tropic: small thermal safety margin, GW -> extinction

  in temperate: larger thermal safety margin, GW -> warmer winters enhance fitness
• GW, populations shift to higher elevations towards northern latitudes where temp is cooler. plants are more sedentary, rate of CC > migration rate -> extinction if cannot migrate fast enough
• exstrinsic incubation period


  time for dengue virus to develop in a mosquito before it is infectious to humans
• problems migrating organisms face:

  • compete with native species for food
  • new predators
  • exposure to new diseases
  • predators separated from prey, food web disrupted
• symbiotic relationship between zooxanthellae and coral

  • algae photosynthesises, producing chem E for corals
  • algae absorbs light energy, protecting coral from harmful effects of sunlight
  • carbon dioxide from the coral respiration can be used for photosynthesis
  • nitrogenous waste from corals serve as nutrients to algae
• coral bleaching 


  GW -> zooxanthellae leave corals
• 1. Female Aedes aegypti mosquito lays eggs above the waterline in places where water collects
  2. water level rises when it rains, eggs get submerged in water, hatch and larvae emerges after 1-2 days
  3. larvae go through four larval stages and gets bigger between each stage.
  4. feed on organic matter in the water and breathe oxygen through a siphon held above the water surface
  5. After four days, the larva develops into a pupa
  6. Pupae do not feed and will develop into the mosquito’s adult body form in two days
  7. he newly formed adult will emerge after breaking the pupal skin
• ectotherms


  organisms inner temperature is affected by external environment
• thermal safety margin


  difference between an insect’s optimum temperature and the current climate it is living in
• malaria is a disease caused by protozoan parasite, transmitted to humans by the anopheles mosquito