impacts of climate change

Question 1

Examples of positive feedback mechanisms

Answer 1

• Reductions in marine productivity
• Release of methane from seafloor/permafrost
• Amplified fire and decomposition
• Increased albedo

Question 2

Decline in krill abundance due to sea ice declines

Answer 2

• Krill feed on algae on bottom of sea ice
• Very important in global food chain

Question 3

Range shifts

Answer 3

• Changes to ranges of habitat latitudinally
• Tundra and deserts moving to higher latitudes
• Increased shrub cover from 1940s
• Changes to ranges in habitat altitudinally
• 2000-2010, 70% treelines moved upwards, average of 1.2m per year
• Extinction of low altitude Pika populations (USA)

Question 4

implications of range shifts

Answer 4

• Hydridisation e.g. pizzly bear
• Invasive species
• Habitat loss
• Predators
• Parasites and vectors

Question 5

Phenological changes

Answer 5

• Spring on average 6-8 days earlier (1971-2000)
• Birds migrate in SE Australia 7 days earlier, disjunct with food availability
• Plankton have shifted northwards (high plasticity), post-smolt Atlantic salmon arrive at feeding grounds with no plankton (low plasticity)

Question 6

Habitat change

Answer 6

• Heat sensitive species
• Habitat loss, chironomid flies, loss of glacial meltwater, polar bears, loss of ice cover
• Sea level rise, coastal and wetland species
• Dry forests become more deciduous
• Increased seasonality in tropical rainforests
• Decreased clouds in cloud forests
• Droughts
• Changes in coastal winds
• Temperature dependent sex determination, sea turtles, males below 27.7C