Climate change Flashcards
how is the climate changing
The climate has always undergone periods of stability and periods of change
the climate has generally been warmer than it is today but ecosystems are adapted for current conditions which are dramatically changing, periods of rapid climate change both hot or cold are associated with mass extinction
why is the difference is climate changes occurring now different than the changes occurring in the past
after a period of being cool we are no experiencing rapid warming at a rate 10 times faster than seen in fast warming events (4-7 degrees over 5000 years)
what are the causes of anthropogenic climate change
green house gasses in the atmosphere
= prevents the suns heat escaping which is essential for life
anthropogenic related activities have increased green house gas production causing rapid increases in temperature
- 97% of scientists are in consensus that it is humans causing this increase in temp
what are the main greenhouse gasses causing temperature rises
CO2
- the previous high reached 300 parts per million around 300,000 years ago
- now the average is around 424 parts per million since may 2023
- a result almost entirely resulting from burning fossil fuels
- co2 can be measured using ice cores to compare to previous levels
what is the second leading greenhouse gas for climate change and what are its sources
methane
increased by about 150% since 1750
- livestock production
- waste management
- release from sediments e.g. artic previously encased in permafrost
what are the environmental consequences of global climate change
1) changes in rainfall patterns
2) melting sea ice, especially in Artic
3) rising sea levels/ ocean acidification
4) increases in extremes of heat, heavy rainfall and agricultural/ecological drought
what is the future of climate change
we are currently at 1.2 degrees above preindustrial levels but could reach 4 degrees by the end of the century unless large changes are made on a global level
what affect does environmental change have on fitness
alters the adaptive peak of high fitness
as climate changes species may find themselves maladapted to new conditions in their habitat. If they continue to change it moves outside of species climatic niche so species must change to persist, this can occur in three ways
what are the three ways species can change to remain in their climatic niche to persist in their habitat
1) change of local phenotype, altering morphology, physiology and behaviour to become better suited to local conditions
2) change of phenology= altering time of life cycle events such as reproduction or migration in order to adjust important biological activities to be better suited to environment
3) shift spatial distributions and move to more environmental conditions
These responses can arise either by phenotypic plasticity in those individuals whose genotypes have the ability to express different phenotypes under different environmental conditions, or via genetic adaptation, whereby intraspecific variation within the population’s gene pool allows natural selection to weed out less fit phenotypes.
what are the different responses to climate change
1) extinction
2) geographic range shifts
3)altered phonologies’
4)biome regime shifts
outline the extinction response to climate change
if unable to change rapidly extinction will occur
- the mean extinction risk from all studies is 7.9% with 95% confidence
- future extinction risk from climate change depends on the future climate scenarios
which taxonomic groups are most at risk from extinction as a result of climate change
some groups are more vulnerable than others
1) amphibians and reptiles are terrestrial endotherms so vulnerable to temp changes
- temp also has an effect on sex determination
2) areas with endemic species that have small ranges
what was the first species to go extinct due to anthropogenic climate change
the bramble cay melomys
- so far few extinctions 33/872 but climate chnage has increased risk of extinction of species by 14% so far
- local extinctions more common
how has climate change lead to geographic range shift and what did Hickling et al conlcude
many species are moving away from the equator as temperature rises
-Hickling et al found that 84% of 329 British species showed clear evidence of northward range shifts between 1960 and 2000
- eventually there will be no more habitat to move into
- marine species are also shifting at a faster rate than terrestrial species
give some examples of altered phenologies as a result of climate chnage
1) Japanese cherry blossoms are blossoming earlier, as early as late march to may
2) timing of reproduction of great tits has not changed with climate but peak data for caterpillars, their food source has= reduction in fitness of late-laying birds
