Greenhouse Gas Emissions Inventory

Introduction

Overview

The greenhouse effect is a natural phenomenon produced when the solar energy reradiated by the earth is trapped by atmospheric gases. The radiatively-active gases that absorb some of this energy in the atmosphere are called greenhouse gases. These are mainly water vapor, carbon dioxide, methane, nitrous oxides, and ozone. Clorofluorocarbons and some photochemical gases, such as carbon monoxide, nitrogen oxides, and non-methane volatile organic compounds contribute also to the greenhouse effect. As a result, the earth stays warmer than it would otherwise be without the presence of the greenhouse gases.

Atmospheric concentrations of these gases have been increasing as a result of a wide range of human activities and have been especially noticeable after the 1950«s. This increase is believed to alter the redistribution of energy in the atmosphere and, consequently, affect climate by altering some related natural phenomenon, such as increment of mean global temperature, changes in frequency and distribution of precipitation, circulation and weather patterns, and hydrological cycle, among others.

Not all atmospheric gases have the same contribution to the greenhouse effect. Direct and indirect effects have been reported in order to make a distinction between a greenhouse gas itself and a gas that produces or can influence a greenhouse gas in the atmosphere. For this reason, an index has been developed to compare the effects of these gases on the same basis. This is called Global Warming Potential (GWP), and it measures the ratio of both direct and indirect radiative forcing from one unit of a greenhouse gas to one unit of carbon dioxide, over a given period of time (carbon dioxide is used as the reference gas). The periods that have been commonly used are 20 or a 100 years. For example, for 100 year period, a Global Warming Potential of 24.5 has been used for methane to measure direct and indirect effects. On the other hand, a GWP of 320 has been recommended for nitrous oxides, to account for the direct effects (WMO/UNEP, 1994).

The possibility of a global climate change, as a result of anthropogenic emissions of greenhouse gases, has become a major concern within the international scientific community in the last few years. This concern was the basis for the creation of the Intergovernmental Panel on Climate change(IPCC) and for the process of international negotiations that led to the approval of the United Nations Framework Convention on Climate Change. The convention was signed by 155 countries at the 1992 Earth Summit, held in Rio de Janeiro, Brazil.

The objective of the Convention on Climate Change is to Çachieve stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate systemÈ. This level should be achieved Çwithin a time frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable mannerÈ.

The Government of Venezuela signed the United Nations Framework Convention on Climate Change (UNFCCC) in June 1992, which was ratified by the National Congress in December 1994. As the Convention requires all parties to develop and publish national inventories of anthropogenic greenhouse gas emissions as well as national plans to reduce or control emissions, the Ministry of Environment and Renewable Natural Resources and the Ministry of Energy and Mines developed the ÇCountry Study to Address Climate ChangeÈ. The study was initiated in October 1993, with the financial and technical assistance of the Government of United States, through the U.S. Country Studies Program (USCSP), and the Global Environment Facility (GEF), through the United Nations Environment Programme (UNEP).

A study of this kind is very important for a developing country like Venezuela, whose national plans include, among others, industrial development programs, improvement of public services, and expansion of the petroleum industry, all of which will likely contribute to increasing greenhouse gas emissions, unless specific programs of energy efficiency and conservation are implemented in the near future. These development plans have also affected extensive forest areas as the establishment of a wide range of economic activities has been traditionally linked to land clearing. On the other hand, the National Government has formulated land use plans at the national and state levels as well as the strategies to implement these plans, in order to foster conservation practices and sustainable management of natural resources. However, natural and human induced risks should be taken into account while developing and implementing these plans. Sea level rise as a result of climate change is one of those risks that will need to be addressed in the future.

Background Information

Venezuela is located in the northern part of South America, between 60 and 75 degrees Longitude West, 2 and 13 degrees Latitude North. The country has a total land area of 916,445 km2, divided into 22 States and 1 Federal District, with a population of approximately 20 million inhabitants.

The country is characterized by three distinctive geographic regions: the Andes Mountains in the West, the Interior Plains (lowlands) in the Center, South-West and East, and the Lofty Plateau in the South. It has about 3,000 Km. of coastline, apart from insular territories and the Delta zone of the Orinoco river, with important coastal marine ecosystems, canals for navigation, and recreational beaches.

The capital, Caracas, is located in the central northern coastal region. This region pioneered the sprout of industries during the 1950âs as a consequence of the incentives given during those years to industrial development; therefore, most of the population and major industrial areas are located in this zone and in the basin of Lake Maracaibo (western area). The north western and north eastern regions concentrate the biggest hydrocarbon production, which represents the main source of revenues of the country. The most important heavy industries (aluminum and steel) and hydroelectric development are located in the southern region. Agriculture and animal husbandry is found mainly in the Llanos and forestry in the western, south eastern and Guayana regions.

Although Venezuela has a relatively extensive territory and a moderate population, the concentration of populated areas and industrial activity on the central-northern coastline generates environmental problems of different nature, including air and water pollution as well as an excess of solid waste production. On the other hand, the country still preserves a considerable area of natural forests that act as reservoirs and sinks greenhouse gases: more than 50% of the territory is occupied by several types of forest, including a high percentage of humid tropical forest.

All these and other relevant natural and socio-economic characteristics of the country as well as the main environmental issues associated with the establishment and development of economic activities have been taken into consideration in the development of the Country Study to Address Climate Change, This analysis was aimed at ensuring that the most important areas would be appropiately covered by the study.

Venezuelan Case Study to Address Climate Change

A team of experts from several Venezuelan ministries and institutions are in charge of conducting this study, with the following objectives:

(i) Develop a national inventory of anthropogenic emissions by sources and removals by sinks of all greenhouse gases in accordance with the IPCC/OECD guidelines.

(ii) Predict future greenhouse gas emissions under various economic development scenarios.

(iii) Identify, analyze, and rank abatement strategies through the formulation of a national plan to mitigate greenhouse gas emissions in the country and enhance reservoirs and sinks.

(iv) Assess the potential impacts generated by sea level rise on selected Venezuelan coastal areas and outline the possible adaptation responses.

(v) Assess the potential impacts of climate change on Venezuelan Forests.

Based on these objectives, the study was subdivided in three interrelated modules:

Module I: Inventories of sources and sinks of greenhouse gases

Module II: Mitigation strategies

Module III: Vulnerability and adaptation assessment of sea level rise and impacts climate change on forests.

The case study has been coordinated by the Ministry of Environment and Renewable Natural Resources (MARNR) and the Ministry of Energy and Mines (MEM), under a global administration by the Office of International Affairs, MARNR.This study has also involved a large number of Venezuelan energy and environmental offices in a first-of-its-kind analysis, and has allowed local experts to gain extensive experience and training to perform similar analysis in the future and assess, with greater expertise, different climate change issues in the country.

The final reports of the different modules will be the basis for the preparation of the national climate change action plan, which will be released as official documents of the Government of Venezuela as a first step to implementing the guidelines set forth in the United Nations Framework Convention on Climate Change.

Venezuelan Greenhouse Gas Inventory

This document presents the results of the inventory of greenhouse gas emissions for Venezuela for 1990, which corresponds to Module I of the National Study to Address Climate Change. Besides the inventory results, the document provides a general overview of the main anthropogenic activities responsible for these emissions and removals as well as a description of particular situations that could influence the results of the inventory.

The gases included in this inventory are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), nitrogen oxides (NOx), carbon monoxide (CO), and non-methane volatile organic compounds (NMVOCs). Chlorofluorocarbons are excluded as they are controlled by the Montreal Protocol.

Specific discussions on methodologies, data used, and information sources for each category are also provided. The assumptions made to perform some of the estimates are described in the related section while detailed calculations are included throughout the document, in the chapters describing each category, along with summary tables.

The methodology used is based on the IPCC Guidelines for National Greenhouse Gas Inventories (IPCC/OECD, 1995), which seek to both ensure consistency and transparency of emission inventories and make possible comparative analysis of results reported by countries. The analysis and results are then presented in accordance with these guidelines, following the reporting instruction tables.

The inventory is presented in different sections, according to the main source categories identified by the IPCC Draft Guidelines for National Greenhouse Gas Inventories. The first section corresponds to the energy sector, subdivided in 1) emissions from combustion, which provides an analysis of carbon dioxide emissions and other gases separately; and 2) fugitive emissions from the oil and gas industry and coal mining activities.

The second section covers the agricultural sector, and includes domestic animals (enteric fermentation and manure management), rice cultivation, savanna burning, agricultural residue burning, and agricultural soil management (fertilizer use).

The third section deals with land use changes and forests, and provides greenhouse gas emission estimates from land clearing, carbon fluxes from forestry management, and carbon dioxide emissions from conversion of grasslands to cultivated lands.

The last section covers emissions from wastes, subdivided in sanitary landfills and wastewater treatment.

Emissions from industrial processes were not developed as a separate section since only cement production was evaluated. However, the related emissions are accounted for in the national inventory. Emissions from the use of solvents were not considered since most of the required data for calculation were not available.

On the hand, an information system (called INVENE) was developed in order to process and manage all the data used for the greenhouse gas emission inventory and ensure a practical and reliable process to update the information and the emission estimates. Annex 1 presents a general description of the system, which includes and calculation and reporting tables (IPCC, 1994). Annex 2 provides an explanation of both methods Top-Down and Bottom-Up used to estimate CO2 emissions generated by energy combustion, along with a comparative analysis of the results obtained.

It is necessary to emphasize, however, that the inventory results can still be considered preliminary since, although fairly reliable, the inventory can be validated and updated as new data are identified or additional information is generated by local studies and on-going researches.

The preliminary character of the inventory should be kept in mind not to justify errors or possible inconsistencies in the emission estimates from any source, but rather to stress out the fact that the emission inventory is based on a dynamic process, that can be improved as better data become available and as new guidances on the methodology is provided by the IPCC. In any case, this inventory represents a significant step in providing a comprehensive picture of the country«s greenhouse gas emissions, despite its weaknesses and limitations, and constitutes a powerful tool to evaluate and plan the best mitigation strategies that the country could implement to reduce its emissions levels.

In Annex 1, a summary table assesses the completness and quality of estimates of sources and sinks of greenhouse gases. The table also presents the level of documentation and dissaggregation of the categories included in the emission inventory.

Unfortunately, the uncertainties associated with the emissions estimates were not quantified due to limited available information and difficulties to identify the level of reliability of the information used in the inventory. Besides limitations associated with the methodology, the poor quality of some of the data is probably highly responsible for the uncertainties of the results. Special efforts should be made in the near future to solve these crucial issues and produce more accurate national estimates.

In the case of the energy sector, in-depth studies have been already initiated for the main carbon dioxide emission sources, with the objective of improving the inventory and identifying the areas where more effort should be put on in the implementation of mitigation actions. Similarly, as land use-change represents a significant source of carbon dioxide emissions, an initiative is already underway to generate better data on deforestation.

Methane emissions estimates could also be improved if more accurate data is generated, especially on fugitive emissiions at the oil and gas industry. A project will be formulated shortly to address this issue in conjunction with the Venezuelan oil industry. Another area that would require a more detailed analysis relates to savanna burning, as the basic data needed to perform greenhouse emission estimates from this source could be greatly improved.

All these iniciatives, developed within the framework of the Country Study to Address Climate Change, would contribute to both perform a more reliable greenhouse gas emission inventory and outline the national strategies to reduce or mitigate greenhouse gas emissions in the country.

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