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Characterisation Method Information

Characterisation Method Name:

Climate change impact on DALYs

Version:

2000

Date Completed:

2000

Principal Method Name:

Eco-indicator 99: mathematical modelling of FUND on global warming

Method Description:

DALY (Disability Adjusted Life Years)

Description of the problem

There are a few particular difficulties in the modelling of health effects from the greenhouse effect:

1. Climate change does not create much direct damage at present, but the predictions are that the current emissions will create considerable damages in the coming decades and thereafter. This
means we have to resort to scenarios and models that could not be validated by experimental data.
2. The vulnerability of systems at risk is dependent on the development of the economy and society, as some effects can in principle be averted, if proper care is taken.
3. Temperature change has many important positive health effects, next to the negative effects.
4. The greenhouse emissions in Europe will cause damage all over the world.
Due to these special characteristics there is wide disagreement about the consequences of the greenhouse effect. We are confronted with an effect that combines possibly very high damages with very high uncertainties whether the damages will ever occur or not.
Damage to Human Health can occur via several impact pathways to multiple endpoints.

We cannot model all effects, as many effects are too uncertain to quantify. Therefore in the Eco-indicator 99 we could only model the grey areas.

Marginal damages

The quoted studies refer to the total damage of climate change. However, we are only interested in the marginal damage; that is, we would like to know the increase in the damage per ton of CO2.
Unfortunately there are only a few studies addressing this issue. The most important project in this field is the ExternE project. This project aims at calculating the societal, or external costs of energy
production systems in Europe, The project used two models to make the appropriate assessments, the FUND 1.6 and the Open Framework Model. The Open Framework Model, does not address the damage to Human Health very explicitly. The FUND model is therefore the most appropriate to use here.
Basically the FUND model is a benchmarking model, that, like we have seen before, calculates the total damage at a doubling of the CO2 concentration. It models: dryland loss, wetland loss, coastal protection, migration, agriculture, heat stress, cold stress, malaria, tropical cyclone, extratropical storms, river floods and unmanaged ecosystems in nine regions of the world. For the ExternE project, it was adapted to calculate marginal damages.
After experiencing many difficulties in trying to interpret this study in such a way that the result could be expressed as DALYs per ton of greenhouse gases, Tol was willing to make a number of special calculations for this project. Tol used the latest version of the FUND model, quoted above (version
2.0). The results have been presented to Hofstetter in the form of excel tables and some personal communication 12 [TOL 1999B]
The procedure can be summarised as follows:
1. Tol made a model run of the so-called IPCC(Intergovernmental Panel on Climate Change) IS92a scenario, and calculated damages for each year between 2000 and 2200.
2. Tol repeated this process three times and added a flow of 1Mt per year of CO2, CH4 and N2O respectively.
3. The differences between these runs were interpreted as the marginal damage
The results include change in deaths due to malaria, schistosomiasis, dengue fever, cardiovascular and respiratory disorders, all due to changes of the average temperature. Next to this, the number of people which have to be displaced due to sea level rise were calculated.

All these parameters are calculated for nine world regions. Unlike the other impact categories, the greenhouse gases emitted in Europe contribute to damages all over the world.
The data used on health effects in the Fund model is to a large degree coming from Martens and Kalkstein et al, see above, however Tol made a number of changes. He assumes that people with an
income higher than $ 3100 do not get Malaria, Dengue and Schistosomiasis, as these people can afford prevention. Furthermore he excludes information of Kalkstein on the increase of extreme hot days.

Dealing with negative damages
An interesting result of the calculations is, that there are also negative damages to Human Health. The calculations show that the number of cold–related cases of cardiovascular disease decreases considerably if the average temperature increases. As a result the decrease of cold related cardiovascular diseases is up to a factor 5 bigger than the increase of heat related cardiovascular diseases. However, as cardiovascular diseases contribute relatively little to the total health damage the overall effect is not so significant.
However, this result prompts a number of fundamental questions:
• In general the negative damages are left out in LCA impact assessment. The question is, if it is justified to follow this general principle here?.
• What are the ethical consequences of allowing negative effects to be compensated by positive effects in the case of Human Health. Is it justified to tell people that suffer from malaria in Africa,
or that are displaced from Polynesia that their problem is outweighed by health improvements in Finland, and that in general the world is happy with the climate change?
The following compromise has been made:
1. The positive and negative damages within a world region are allowed to compensate each other.
For instance a damage in Italy, can be compensated by a negative damage in Denmark.
2. The positive and negative damages are not allowed to compensate each other between the 9 world regions. This choice has also a pragmatic background, as it is difficult to separate positive and negative effects
within a region, due to some modelling restrictions.

Damage modelling

The calculation results make reference to no less than 6 endpoints for which DALYs have to be calculated. Tol also calculated DALYs but these have not been used, because the calculation procedure seems different from our standard approach.

Extrapolation to other greenhouse gases
The extrapolation of the damages from the three gases to the full range of greenhouse gasses can be done with the umbrella principle [HOFSTETTER 1998], also used in the case photochemical ozone
creation. The most recent list of equivalency potentials is provided by [SCHIMEL ET AL 1996]. The list
is developed for three time perspectives. The perspective for 100 years fits best for the calculations of Tol.
However, the lifetime of the gases is not only responsible for the magnitude of the radiative forcing, but also on the question whether health benefits or damages occur. Substances with a short lifetime appear
to have greater benefits than substances with a longer lifetime.
According to Tol [personal communication] the equivalency factors can lead to misleading results. In fact all gases need to be treated separately through the FUND model. As this was not feasible within the
budget of this project the following solution has been found:
• Gases with a lifetime below 20 years behave like methane in the damage model
• Gases with a lifetime between 20 and 110 years behave like CO2 in the damage model
• Gases with a lifetime above 110 years behave like N2O in the damage model
The damage of greenhouse gas i can now be calculated as:
GWPi * Drefsub/GWPrefsub In which Drefsub represents the damage factor for either CO2(as C), CH4 or N2O, and GWPrefsub represents the global warming potential for one of the three reference substances.

Literature Reference:

1. [Hofstetter 1998] Hofstetter, P. (1998): Perspectives in Life Cycle Impact Assessment; A Structured Approach to Combine Models of the Technosphere, Ecosphere and Valuesphere. , Kluwers Academic Publishers, 1998, Info: www.wkap.nl/book.htm/07923-8377-X. 2. [Schimel et al 1996] Schimel D., D. Alves, I. Enting et al.(1996), Radiative forcing of Climate Change, in J.T. Houghton, L.G. Meira Filho, B.A. Collander et al.(eds.), Climate Change 1995; The Science of Climate Change, WG I of IPCC, Cambridge University Press, Cambridge

Methodological Range:

Geographical range is Europe Data are based on hierarchist perspective

Notes:

Existing Characterisation Factors of Climate change impact on DALYs

Characterisation Parameter

Category Indicator

Impact Indication Principle

Aspect

Substance

Quantity

Unit

Notes

CFactor

DALYs