An eyeglass on our planet

Reuben Sessa and Jeff Tschirley

Global environmental change and the sustainability of human development have been of major concern during the 1990s and were reflected in the Earth Summit which took place in Rio de Janeiro in June 1992. There is also a general realization that the scientific data and information required to assess and understand the nature of change are woefully inadequate. This has prompted a number of United Nations organizations and the international scientific community to create three global observing systems (Climate, Oceans and Terrestrial) to ensure that the observations and information needed to address global issues were obtained and made available to all potential users.

The Global Terrestrial Observing System (GTOS) is the youngest of these observing systems and faces the complex task of providing the scientific and policy-making community with access to the data they need to detect and understand the changes in terrestrial ecosystems. No easy task considering the wealth of different ecosystems, the lack of data from certain regions and the human dimension that dominates all policy options. Since its establishment in 1996 the aim of GTOS has been to improve the quality, coverage and accessibility of terrestrial ecosystem data. For example, since all global datasets begin with a measurement at a specific place, regional GTOS programmes were developed as a means to better assess the user needs and national capacity to collect and analyse data.

The continuing problem of accessibility to terrestrial data is being addressed by GTOS, through the Terrestrial Ecosystem Monitoring Sites (TEMS) database which is an international directory of sites and networks that carry out long-term terrestrial monitoring and research. The new version of TEMS ( was launched in May 2001 and provides information on the ‘who is measuring what and where’ in terrestrial environmental monitoring.

TEMS is best described as an online ‘yellow pages’ where users can find sites that measure any of 110 variables. The data can be searched through tables, maps, and tree diagrams allowing users to quickly locate the information they require. TEMS ‘modules’ contain sites and other relevant information for key GTOS research topics such as biodiversity, coastal areas, desertification, mountains, net primary productivity and terrestrial carbon. These modules are still under development but they will allow users to access the specific information on their field of interest.

Data incompatibility, when data for the same variable is measured or processed using different methods making them difficult to compare, is another significant constraint in building global terrestrial datasets. TEMS provides methodology sheets for each of its 110 variables that define and characterize the variables, and provide information on the main measurement methods used (units, frequency, accuracy, etc.) and the major holders of such datasets. It is hoped that the information provided in these sheets may contribute to guidelines for future work. More than 60 socio-economic databases have also been identified and described in TEMS in order to promote more integrated and interdisciplinary analysis of terrestrial data.

Although TEMS brings sites together for users, it does not actually initiate collaboration between sites. The Global Terrestrial Observing Network (GT-Net) has been specifically created to bring together existing monitoring sites and networks with similar objectives. The purpose is to share and exchange data, and to carry out projects to improve the understanding of global and regional change. GT-Net also gives sites and networks a forum to work together on a core set of issues, such as data access and availability, and harmonization of measurement methods. These networks are thematic in nature (ecology, glaciers and permafrost, a hydrology network) or regional (there are currently two demonstration projects in Central and Eastern Europe and South Africa).

The regional programme is particularly important as it builds collaboration among sites and between countries. This allows regional and global gaps to be identified and filled but also increases the free exchange of data needed for developing and implementing national, regional and global programmes. In both GTOS regional projects the biggest problem identified by scientists is that routinely collected data is often not properly processed, stored, indexed, or integrated with other information. This causes data to be unusable or inaccessible to other potential users. GTOS has therefore helped in initiating the development of suitable infrastructures that are required. GTOS has also organized a series of workshops used to train scientists on data management and accessibility methods (see for details on the latest workshops).

Recent workshops in the Southern African region have been dedicated to the use of management information system technology for managing text, database and map data on a single information platform. The Knowledge Information System Software (KISS) allows information to be more accessible through two tools: Dynamic Maps and Dynamic Knowledge. The first of these workshops took place in Lusaka (Zambia) in May 2001 and the second was held in Harare (Zimbabwe) in September 2001 (

GTOS projects such as the Terrestrial Carbon Observation (TCO) theme respond to the needs of the policy and scientific communities for data on the terrestrial component of the global carbon cycle. TCO uses satellite and in situ measurements and models to estimate carbon fluxes between the terrestrial surface and the atmosphere. The data will then be used to generate maps of terrestrial carbon sources and sinks on a seasonal, annual, inter-annual and decadal basis. So far the experts working on the project have identified the observations required, the key gaps that need to be filled, and assessed quality of the existing data.

The satellite community is far ahead of the in situ scientists in their capacity to make carbon cycle observations and generate global products. To help bridge this gap scientists who manage significant projects or large networks that generate terrestrial carbon data and information were brought together in June 2001 in order to begin putting into place the mechanisms needed to systematically collect the in situ data that are required. This is a key step in achieving the goal of estimating annual land-atmosphere fluxes and producing flux emission estimate maps which can be used by policy and decision makers.

Supplementary to TCO is the Net Primary Productivity (NPP) demonstration project. NPP is the amount of new plant growth within a given area over a specified time. It is therefore a key input to the carbon budget, but is also an important indicator of ecosystem health and functioning. In agriculture, NPP also closely reflects the grain yield. It is a key indicator widely used to estimate the levels of carbon uptake and respiration. The NPP project uses measurements obtained from ecological sites to validate the data streams produced by NASA’s Moderate Imaging Spectrometer (MODIS) sensor. The validated imagery will then be used to generate regionally specific crop, range and forest yield maps for land management applications. Currently, 45 sites in 12 countries have agreed to participate in the NPP project.

These examples are just a drop in the ocean of information needed to understand and estimate the impacts of global and regional environmental change. Identifying the mechanisms, interactions, and effects that occur in different parts of the planet is no easy task. An even greater challenge will be to accurately ascertain how human activities influence global climate and how this will affect the planet. Fortunately, there is a considerable amount of ‘common cause’ within the community of terrestrial scientists to overcome these problems.

The important constraints in improving the quality and availability of terrestrial data are weak institution structure at the international level, data fragmentation and limited experience or practice of interdisciplinary collaboration among scientists. Without going into detail on each of these issues, suffice it to say that if terrestrial science (scientists, ecologists, hydrologists, foresters, etc.) is to contribute to global change studies in the way that is expected, considerable additional investment will be needed from national governments to support a variety of international efforts aimed at filling data gaps, answering key research questions, undertaking data assimilation exercises, building and linking research networks, and strengthening the capacity to collect data in the developing country regions. The work carried out by GTOS is just the welcome umbrella for building the observational infrastructure needed to address the many questions and uncertainties related to large-scale environmental change

To learn more about GTOS, please visit the following links:

Terrestrial carbon:

Terrestrial monitoring sites (TEMS):

GTOS in Africa and Europe:

GTOS home:

or write to the Secretariat:

This issue:
Contents | Editorial K. Toepfer | Answering poor health | Tackling water poverty | Everything connects | Up the gross natural product | Stopping AIDS | Whose city is it anyway? | Nutrition | At a glance: Poverty | Competition | World Bank Special: ‘Double burden’ | It’s not just, pollution | Smoke and fires | Breaking the cycle of poison | Pharmacies for life | Viewpoint: Change – or decay | The environment: why we must not give up | World Atlas of Coral Reefs | GTOS: An eyeglass on our planet | GTOS: An eyeglass on our planet

Complementary articles in other issues:
Tim Foresman: On The Dot (Transport and Communications) 2000

AAAS Atlas of Population and Environment: