REPOSITORY > RESULTS

Abstract

It is evident that the worldwide average temperature is rising and climate is changing (WMO, 2003) and it
is believed that there is sufficient evidence that this is due to human activities (IPCC 2001). Human
activities are primarily responsible for the release of carbon dioxide and other global warming pollutants
which are causing a change in the composition of the atmosphere and its properties.
We have developed the global energy-climate model (GEC model) for the purpose of investigating the
dependence of the Earth's temperature on the concentration of carbon dioxide in atmosphere. Global
energy-climate model (GEC model) was constructed in the STELLA program, which makes use of Systems
Dynamics Modeling (SDM) as a methodology. GEC model connects interactions between Earth's
temperature, CO2 emissions from coal, petroleum and natural gas. GEC model consists of three main
sectors: Climate sector, energy consumption sector and CO2 emission sector. Together, the interacting
climate, energy consumption and CO2 emissions sectors provide predictions of both Earth’s and
atmosphere temperature as a function of time. After the running of the climate sector, in this case, we have
to deal with the zero-energy balance model, for which constant temperatures are obtained for the
temperature of the atmosphere 255 K = -18 0C and 288 K = 15 0C for the temperature of the Earth. After
the execution of the GEC model a gradual increase in atmosphere’s and Earth’s temperatures is obtained.
This increase is due to the connection between the sectors of energy consumption, CO2 emission and
climate system. In this case the GHG effect is taken into consideration. We obtain a predicted increase of
mean temperature for the time interval of 100 years of about 5 K, which is in accordance with the data
obtained from IPCC for the same time interval, which is approximately 7 K.
The response of the climate system to anthropogenic forcing includes the potential for ‘rapid climate
change’. Rapid climate changes with their impacts are investigated in this thesis. The results obtained in
this work show that increasing the rate of rapid climate changes can be associated also with nonlinear
responses of economic and ecological factors.
Reducing emissions a small percentage below 1990 levels over the next 5 to 25 years could be one way
to react and prevent negative impacts from climate change. These negative impacts affect mainly economic
and ecologic systems. From the analysis of the results obtained, we can conclude that a great impact on the
factors discussed has the decreasing rate of pollution, but in long-term, of much more importance is the
year of achieving the pollution reduction.