ANNEX 5: SBSTA INPUT (PRELIMINARY DRAFT)

1. Introduction

It has been concluded by the IPCC that the global climate system is changing and that one of the components of that change is human intervention in the form of anthropogenic emissions of greenhouse gases and changes in land use.

In the development of response strategies to such changes in the climate system requires an understanding of the extent to which land surface changes are a contributing factor; the extent to which the terrestrial ecosystem is changing as a result of climate change and; the implication of these changes in the terrestrial ecosystem on food productivity, ecosystem-based economic development and the availability of clean fresh water.

While it is essential to be able to assess the magnitude of any ecosystem changes it is even more important to be able to assess the rate of such changes and any change in the frequency of extreme events. It is likely to be such rate and extreme event changes that dictate the speed at which governments may have to take action. The result of a focus on the rates of change has profound implications for the nature of the observing systems that are established to assess and monitor the Earth system. It means that systems must be operated over periods of decades rather than weeks, months or even years. Such observing systems, while they can be built upon research initiatives, must evolve into operational undertakings with solid commitments to manage a range of important issues which include instrument inter-comparison; site documentation; quality control and the long term archiving of data; and avoidance of the loss of essential data sets due to changes in personnel and programs.

The terrestrial observing system required to respond to these needs is in its infancy, much of it clearly lacking the maturity of the atmospheric system that has been in place for nearly a century or even the ocean system that has been in development for some time. At this time it is fair to say that there is almost no operational terrestrial observing system. There exist various components, mainly of research nature, that could evolve into the nucleus of an operational terrestrial observing system. Such evolution will require a sustained commitment by governments and both regional and international agencies to undertake new research initiatives and to ensure that critical observing sites and systems are maintained well into the foreseeable future.

Given the need to observe a large number of variables in a consistent manner at local, regional and global scales, it will be necessary to use satellite observation techniques to the maximum extent possible. At the same time there will be an on-going requirement for in situ observations for the validation and inter-comparison of satellite sensors in key locations around the globe. This commitment to the use of satellites in an operational observing system implies a significant investment on the part of the space agencies to provide a continuous program of specific sensor observations into the foreseeable future. At the same time the research community must identify as a matter of priority a limited set of indicators that can report on the health and viability of the terrestrial ecosystems.

At this time it is suggested that specific attention be paid to the following components of an initial terrestrial observing systems.

2. Land Use and Land Cover Change

Changes in land use and land cover strongly influence the climate system. Human activities now dominate many aspect and processes of ecosystems world-wide (Vitousek et al., 1997). This domination has lead to an increase in trace-gas emissions from land use to the atmosphere, to a globally decreased carbon content in terrestrial vegetation and soils, and to altered land-surface characteristics. These changes have already led to local, regional and global changes in climate. Both natural forests and wetlands have ver the last century been converted world-wide to agricultural land, managed plantations and pastures. The decrease in forest and wetland extent is, however, not the only change. Subtle modifications of the original land cover, such as the removal of selected timber species, habitat fragmentation, nutrients addition from air pollution, water drainage and land degradation, also have altered the original land cover characteristics considerably.

Adequate observation of land cover conversion and modification has been problematic up to now. Regional and national land-use statistics and satellite observations show different rates of change. These differences are partly due to the complexity of the different spatial and temporal scales involved and to the obvious reversibility of some of the changes. For example, converted land is often is abandoned after a few years of use it returns again to more natural conditions (Skole and Tucker, 1993). Monitoring of land-use and land-cover change therefore requires a continuous monitoring to be able to adequately quantify the relevant changes.

Budget for the land-cover observation:

3. Net Primary Productivity

This variable measures the growth rate of plants on which the functioning of both natural ecosystems and the human food and fiber producing systems depends. At a hemispheric scale it can be monitored through the seasonal variation in the atmospheric carbon dioxide concentration as provided by GAW observatories. It is central to the terrestrial ecosystem carbon sink which is known to account for about a fifth of the global net carbon flux. Regional location and quantification of this sink is technically possible and would require an intensification and long term commitment to the global flask sample network particularly in oceanic tropical and southern hemispheric locations. Precise, calibrated isotopic analysis requiring centralised facilities is essential. Finer scale monitoring and mapping of NPP relies on a combination of satellite-sensed absorption of photosynthetically active radiation by the vegetation cover (indices such as the Leaf Area Index or the Fraction of Photosynthetically Active Radation) and simulation models which require soil, climate and land cover data for acceptable accuracy.

The emerging research network of land-based CO₂ flux towers is crucial for the validation of the satellite and model-based estimates. It needs to find support to continue in the longer term as a monitoring activity.

Budget for net primary productivity:

4. Fires

Biomass burning is both a globally important source of aerosols and greenhouse gases and a sensitive indicator of the disturbances associated with the adaptation of vegetation to a changing climate. There is currently no integrated global observing system for fires although there are several research projects which have demonstrated the technical feasibility of doing so, using a variety of satellite based sensors. This variable has strong links to the land cover variable since fire is an important agent of land cover change and the emissions from fires depend on the cover type burned.

Budget for fires:

5. Water Resources

There is no existing mechanism for the assembly of water resource information at the required spatial and temporal scales. For some observations (e.g., run-off data, GRDC) institutional mechanisms are in place, although there is a need to change the frequency and the form in which the data are provided. However, many nations have never or are no longer able to supply GRDC with the required data because they lack the required financial resources and trained man-power. For other observations, e.g. changes (particularly declines) in water tables, there is no global mechanism and limited national capabilities. Part of the gap is being addressed through (WHYCOS), but this initiative is largely focused on the Mediterranean and Africa and it needs to be extended to other regions. Some x? sites are required at approximately US$50,000/site. In addition in those areas where human development is heavily dependent on ground water resources which are already under great pressure there is a need for monitoring wells that are measuring both quantitative and qualitative changes. Several hundred monitoring wells are required at the cost of some US$50,000/well and a new institutional mechanism for ensuring that the information meets local development and management needs and is shared with other communities at the regional scale.

6. Glaciers

Mountain glaciers account for only about one percent of global ice volume but they are much more sensitive indicators of decadal to century scale climate changes than the Greenland and Antarctic ice sheets. They are also of considerable economic importance (water resources, hydro-power, tourism) in many alpine countries.

Annual mass balance surveys are carried out for only about 50, mostly small, glaciers world-wide and the observations are not satisfactorily distributed to represent either the major climate zones or the estimated regional ice-melt contributions to global sea level rise. Glaciers account for about 15-20 percent of the ocean level rise in the 20th century. Currently, there is no inventory for over one-half of the world’s glaciers and no global map of land ice areas. Many mass balance survey programs have been discontinued in Canada and the former Soviet Union territory, and in other regions (South America, the Himalayas) there have been few observations of any kind. In the case of Canada the extensive survey records, maps and air photographs assembled at NHRI, Saskatoon are essentially inaccessible and at risk of loss (Barry 1995; Ommaney, 1996).

Suggested Improvements

1. Rescue “at risk” data in Canada, the FSU (central Asia), and elsewhere and archive them in accessible formats/media. Estimated cost: US$75 thousand.

2. Resume discontinued mass balance surveys and initiate new programs at c. 20 well-chosen glaciers. Annual cost/glacier approx. US$10-20 thousand, according to location. The number of long-term continuing sites might be reduced when the representativeness of the sites is determined (e.g. after 5 years).

3. Link the field surveys (on-going and new sites) to the routine satellite monitoring program, Global Land Ice Monitoring from Space (GLIMS) proposed by Dr Hugh Kieffer, USGS, Flagstaff. The project will monitor areal extent, snow line at the end of the annual melt season, velocity field and terminus location using EOS-ASTER data. The field surveys will provide calibration and validation of the ASTER-based data. The GLIMS program is not funded at this time. It depends on partnerships with regional centres responsible for surveys of selected glaciers, retrieval of selected images from the EROS-DAAC and an indexing pointer system and product archived at the NSIDC-DAAC. An estimated annual cost for this 3 year pilot program is approximately US$250 thousand.

4. Accelerate the completion of the complete World Glacier Inventory using air photo and high resolution satellite imagery. The infrequency of Landsat coverage in cloudy regions has meant that images are not available for all areas. Estimated cost for imagery and related data purchases, processing and analysis and digital file preparation: c. US$600-700 thousand.

7. Permafrost

Perennially frozen ground underlies 25 percent of the Earth’s land surface. It is widespread in northern North America, northern Eurasia, north-east China, the Tibetan Plateau and in high mountain regions. Thawing of frozen ground particularly where there is a high ice content, causes ground settlement or subsidence, creep on gentle slopes and landslides on steep slopes with severe damage to buildings, transportation routes, pipelines and other structures unless specialised engineering techniques are used (Melnikov et al 1993). Warming of the ground initially causes the summer “active layer” in the soil to become deeper. Thinning of ground ice (which can be 100s of meters deep in northern Canada, Alaska and Siberia) is a slow process but disappearance of thin patchy permafrost in mountainous regions such as the Alps and along the southern margins poses significant risks to structures and potentially in the sub-Arctic for release of methane. From the global climate change viewpoint, the potential accelerated release of greenhouse gases is the most important concern. Changes in the active layer thickness are also a sensitive indicator of the magnitude and rate of climate change, both globally and regionally.

Extensive amounts of data from thermal wells and other surveys are proprietary or in government geological of transportation agencies are the archives are inaccessible. Many oil and gas exploration company archives are also at risk due to economic circumstances.

Suggested Improvements

1) Seek partnerships with industry to ensure that data will be made available for GTOS/GCOS when its confidentiality is no longer essential.

2) Digitize extensive government agency records (US and Canadian Geological Survey) and archive them.

3) Estimated cost:

(The Russian data include surface to 3m temperatures and bore-hole data held at many institutions and the Council for Earth Cryology).

4) Augment the network of thermal wells inn areas where coverage (or data) are lacking.

8. References

Skole, D. and Tucker, C., 1993. Tropical deforestation and habitat fragmentation in the Amazon: Satellite data from 1978 to 1988. Science, 260: 1905-1910.

Vitousek, P.M., Mooney, H.A., Lubchenko, J. and Melillo, J.M., 1997. Human domination of earth's ecosystems. Science, 277: 494-499.