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CHAPTER 23: IMPACTS AND CONSEQUENCES OF CLIMATE CHANGE (Impact of climate…
CHAPTER 23: IMPACTS AND CONSEQUENCES OF CLIMATE CHANGE
Analysing and reporting on climate change data :pen:
International Panel on Climate Change
Give current internationally accepted understanding of climate change.
Reviews the most current and widely accepted scientific evidence and climate modelling and uses that info to report on the current state, projected impact and likely consequences of climate change.
Low estimate: Annual global carbon emissions fall to 5 gigatonnes by the year 2100
High estimate: Emissions increase to 35 gigatonnes by 2100
came to the conclusion in 2014 that global mean surface air temp is likely to increase between 1.5C and 5.8C by 2100.
Communicating the degree of certainty in assessment :!:
Climate projections can never claim 100% certainty - the accuracy of climate models depend on: their assumptions, the modelling equations that link cause and effect in complex physical, biological and societal processes, the accuracy of data that is put into the model.
Anyone reporting on the predictions should include info on their degree of certainty.
quality of evidence (low, medium, robust)
level of agreement between scientists (low, med, high)
Impact of climate change :explode:
A 1C increase in the global mean temperature is large compared to the natural variability of mean global temperatures over the past 100 years.
A small change in temp can produce quite large climatic changes.
Projecting consequences of the enhanced greenhouse effect on the 4 major Earth systems at specific regions around the world poses uncertainties due largely to how each region will manage these potential consequences.
The overall risks of future climate change impacts can be reduced by limiting the rate and magnitude of climate change, including ocean acidification.
the levels of climate change that will trigger an abrupt and irreversible change is uncertain - but the risks of crossing such thresholds increases with rising temperature (medium confidence).
Water
increased water availability in most tropics and high latitudes
decreasing water availability and increasing drought in mid-latitudes
100s of millions of people exposed to increased water stress
Ecosystems
Up to 30% of species at increasing risk of extinction
Increased coral bleaching,
Increasing species range shifts and wildlife risk
Ecosystem changes due to shifts in atmospheric circulation
Food
Complex, localised negative impacts on small households, subsistence farmers and fishers
Cereal productivity decreases in low and mid-high latitudes
Coasts
Increased damage from floods and storms
About 30% of global coastal wetlands lost
Millions more people could experience coastal flooding each year
Health
Increasing burden from diarrhoeal, cardio-respiratory and infectious disease
Increased morbidity and mortality from heat waves, floods and droughts.
Changes distribution of some disease vectors.
Substantial burden on health services
Impacts on humans and animals and environment :warning:
The range of Amopheles mosquito (carrying malaria) could expand to cover much of Aus. - Increase risk of incsect-borne diseases.
Certain species would have their range fragmented or expanded or loss of bioclimatic range
Decrease in the frequency of extreme cold weather.
Failure of flowers to produce and setting of fruit
Lead to an increase in the frequency of extreme events such as droughts, floods and storms. ( as increased temperatures mean more evaporation and more wind energy) - Evidence: extreme forest fires, extreme storms and flooding.
Positive impacts :<3:
milder winters and warmer conditions in spring - reduction int he frequency of frost damage.
Many pine plantations will produce more wood under changed climate conditions - also due to enhanced photosynthesis brought by higher levels of CO2 in the atmosphere.
Carbon dioxide fertilisation - increases growth in many plant species - also reduced opening of the stomata, causes less water loss from transpiration
These plants will remain prductive is there is reduced soil moisture, allowing them to survive in areas of reduced rainfall as a result of climate change.
Regional Impacts of Climate Change in Australia :explode:
By 2020, significant loss of biodiversity is projected to occur in some ecologically rich sites (Great Barrier Reef & Queensland Wet Tropics)
By 2030, water security problems are projected to intensify in southern and eastern Aus, due to increased drought and fire.
By 2050, ongoing coastal development and population growth in some areas of Aus are projected to exacerbate risks from sea level rise and increases in the severity and frequency of storms and coastal flooding.
STUDY DESIGN
Consequences of changing the composition of gases in the atmosphere
• the impacts for organisms, including humans, and ecosystems of the natural greenhouse effect and the enhanced greenhouse effect
• analysis and reporting of climate data including the interpretation of confidence measures of climate projections (calculation of standard deviation and probabilities are not required)
• projected consequences and uncertainties of the enhanced greenhouse effect on the four major Earth systems (atmosphere, biosphere, hydrosphere, lithosphere), and on the health of living things and on the environment, at a selected location.
