Title: Estimation of Greenhouse Impacts of Continuous Regional Emissions

Author: Jukka Sinisalo

Status: Technical Research Centre of Finland, VTT Publications 338, 1998

Keywords: Greenhouse effect, Air pollution, Environmental effects, Radiative forcing

In this thesis a method to calculate the greenhouse impact of continuous, time-dependent, non-global greenhouse gas emissions is used to estimate the impact of estimated anthropogenic pre-1990 and future (post 1990) emissions of CO2, CH4 and N2O of Finland and Nordic countries. Estimates for the impact of Finnish CFCs and their substitutes and the significance of Finnish forests as carbon sink are also calculated. The method is also used to compare several different wood and peat energy production schemes with fossil fuel use, in terms of caused greenhouse impact. The uncertainty of the results is examined.

The greenhouse impact is measured in this thesis as the global mean direct radiative forcing caused by the emissions. Radiative forcing is the driving force behind the climate change and as such it can be used to assess the ensuing climate change. The method is suitable for greenhouse agents that can be considered to be well mixed in the atmosphere (mainly CO₂, CH₄, N₂O and both CFCs and their substitutes).

According to the results Finnish greenhouse impact due to anthropogenic CO2, CH4 and N2O emissions has increased eight-fold during this century, and will very likely remain higher than current level throughout the next century. The impact of Nordic countries has followed the same general pattern as Finland. It is likely that the per capita radiative forcing of the Nordic countries will remain above the global average.

The uncertainty of the absolute results is quite high due to uncertain knowledge at several stages of the calculation. When the results are used in comparisons (e.g. between emission scenarios, or emissions of different countries), the accuracy of the results increases considerably.