GCOS Implementation Plan - WMO

Implementation Plan for the Global Observing System for Climate in Support of the UNFCCC
(2010 Update)
moisture, lake levels, glaciers, and river discharge constitute critical components of the hydrological
cycle, with often direct impact on water availability and, for instance, on droughts and floods.
Land has a wide variety of natural features, slopes, vegetation and soils that affect water budgets,
carbon fluxes, and the reflective properties of the surface. Land is often covered by vegetation;
importantly, by now, almost 40% of the Earth’s land surface is under some form of management.
Land-use changes the characteristics of the land surface and thus can induce important local climate
effects, especially through changes in albedo, roughness, soil moisture and evapotranspiration. When
large areas are concerned (e.g., as in tropical deforestation) regional and even global climate may be
affected. Some land is covered by snow and ice on a seasonal basis, and this land features glaciers,
ice sheets, permafrost, and frozen lakes. Snow and ice-albedo play an important role in the feedback
to climate. Further, as land-based ice, such as a glacier, melts, it affects rivers and contributes directly
to sea-level rise. Disturbances to land cover (vegetation change, fire, disease and pests) and soils
(e.g., permafrost) have the capacity to alter climate but also respond to climate in a complex manner
through changes in their biogeochemical and physical properties. Precise quantification of the rates of
change of several land components is important to determine whether feedback or amplification
mechanisms through terrestrial processes are operating within the climate system, such as positive
feedback between temperature rise and the carbon cycle. Increasing significance is being placed on
terrestrial data for both fundamental climate understanding and for use in impact and mitigation
assessments.
Atmospheric CO 2 is increasing on a global scale while natural sources, sinks, and stocks, and human
interventions in the carbon cycle vary profoundly within regions. Assessments of regional carbon
budgets help to identify the processes responsible for controlling larger-scale fluxes. A lack of reliable
data at appropriate scales and resolutions prevents the scientific community from making accurate
assessments for the entire globe, but regional-scale carbon budgets provide unique opportunities to
independently verify and link methods and observations over a wide range of spatial scales. For
example, it is possible to compare “top-down” atmospheric inversion estimates with land-based or
ocean-based “bottom-up” direct observations of localized carbon fluxes. On land, as well as in the
oceans, the basic components of such budgets include measurements of carbon stocks and
exchanges with the atmosphere.
The sensitivity of carbon pools to changing climate form highly uncertain components of the regional
and global carbon cycles. The Coupled Carbon Cycle Climate Model Intercomparison Project (C 4 MIP)
showed the large range of future predicted CO 2 concentration, as various models have different
parameterizations of the climate-carbon system. It has become obvious from this intercomparison,
however, that CO 2 levels may increase sharply in the future due to positive feedback between
temperature rise and the carbon cycle.
Foundations exist for both the in situ observing networks and the space-based observing components
of the terrestrial domain ECVs, but these need to be strengthened. Improving understanding of the
terrestrial components of the climate system and of the causes and responses of this system to
change is vital to society, as is assessing the consequences of such change in adapting to and
mitigating climate change. Better observations of the terrestrial carbon-related variables have
assumed greatly increased relevance in the context of implementing the UNFCCC Bali Road Map. 89
6.1.1. Standards
Many organizations make terrestrial observations, for a wide range of purposes. As a result, the same
variable may be measured by different organizations using different measurement protocols. The
resulting lack of homogeneous observations hinders many terrestrial applications and limits the
scientific capacity to monitor the changes relevant to climate and to determine causes of land-surface
changes. The Second Adequacy Report and the IP-04 noted the need for an international framework
to:
• Prepare and issue regulatory and guidance material for making terrestrial observations;
89 For details, including the first UNFCCC COP decision on reducing emissions from deforestation in developing countries, see
UNFCCC (2008): Report of the Conference of the Parties on its thirteenth session, held in Bali from 3 to 15 December 2007,
Addendum, Part two: Decision 2/CP.13 (Reducing emissions from deforestation in developing countries: approaches to
stimulate action), FCCC/CP/2007/6/Add.1, http://unfccc.int/resource/docs/2007/cop13/eng/06a01.pdf#page=9
104