Integrated Assessment

major ecosystem types characterized by dominant vegetation and climate (t°, perecipitations) 

• increasing mean: average t° shifts to higher numbers
• increasing variance: distribution of t° is broader 
• return event increasing
  • from once every 9000 in 2002
  • to once every 2 years in 2100 
• variability increase bc of suppressed cooling effect of evapotranspiration 

• reference point 
• market analysis 
• travel cost approach
• hedonistic price approach 

• avoided damage costs
• expenditure on preventive measures 
• valuation of changes in productivity
• restoration costs 

• direct
  • economic use
  • symbolic values
• indirect
  • functional value 
• option values 

• existence values
• other 

contingent valuation methods: ask about WTP, WTA

• human capital approach: loss of output (change in GDP)
• willingness to accept: compensation accepted for potential damage
• willingness to pay: price to avoid statistical death 

• hedonistic approach
  • wage difference, safety or insurance price, disease preventing costs
• contingent valuation 

1. determine sectoral regional climate impacts in physical terms
2. translate in monetary value using monetizing methods
3. aggregate sectoral and regional results 

result: curve of aggregated global economic damage in $ as a function of t° increase 

• fix objective andapply it to determine backwards the activities necessary to achieve the goal
  • determine damage cost curve
  • determine mitigation cost curve
  • = total cost of climate change
  • derive globally optimal climate protection strategy that minimizes total cost or maximizes total welfare 

considers dynamic relationships in cause effect chain (feedbacks) 

dynamic integrated model of climate and the economy, Nordhaus 1989 

• conceptual, global, intemporal model
• reference case: optimal growth development path neglecting climate problem 
• global output = capital stock x labor force 

1. mu(t): how large emission reduction should be as function of time (% of deviation of reference path) 
2. c(t): the share of global output devoted to consumption (vs investment) 
   1. investment can be used to increase capital stock 

• determine optimal emission path maximizing present value of global welfare 

rate to express future value into present value 

discounted future damage costs < mitigation costs -> future damage costs have no worth today 

• individual level: value loss of life
• intra-generational level: money is worth more in poor regions, would maximize welfare without compensating damages
• inter-generational level: damages for future generations 
• social welfare: ≠ derived from rational individual preferences 
• utility theory: based on subjective probabilities 

• lack of individual decision maker
• utility problems 
• incomplete information 
• -> cannot serve for international decision making
  • need to identify long term objective and define steps to achieve it
  • negotiation process 

• economic growth
• technology
• population
• governance 

• ghg
• aerosols 

• air and sea t°
• precipitation
• snow and ice cover 

• land use
• food and water systems
• ecosytsems and biodiversity
• animal and plant health

society adapts to environmental impacts, autonomous of government driven 

reduces environmental impacts 

is even lower in combination w mitigation 

reduce enhanced ghg, reducing their effect on climate system and natural system 

overall impacts of climate change are reduced, reducing need to adapt

mitigation reduces emissions at start of cycle and throughout the cycle -> reduces risk more than adaptiation 

mitigation = global problem requiring global action, ≠ adaptation which is local