Environmental Data and Scenarios
Welcome to the Environmental Data Section of the Data Distribution Centre (DDC) of the Intergovernmental
Panel on Climate Change (IPCC). Acknowledging that changes in environmental conditions other than climate
may need to be considered when conducting climate change impact and vulnerability assessments,
the Environmental Data pages of the DDC provide access to
and scenario data for a
range of non-climate conditions in the atmospheric, aquatic and terrestrial environments. These
include data on atmospheric composition (e.g. carbon dioxide, ozone), land use and land cover, sea
level, and water availability and quality. Most projections are consistent with the driving factors
and emissions presented in the Special Report on Emissions
Explanations and illustrations of procedures for incorporating this information in impact and vulnerability
assessments can be found on the DDC Guidelines pages. Data for other
environmental variables will be added in due course.
Scenario data for the atmospheric environment
A number of gases and other atmospheric constituents may have important effects on the exposure unit.
Perhaps the most important of these is carbon dioxide. CO2 is well mixed in the atmosphere, so
observations of concentrations from a single site are adequate for most impact applications.
CO2 concentration is commonly required as a direct input to models of plant growth, since it can affect
both the growth and water use of many plants. Since it is also a major greenhouse gas associated with
global climate change, the CO2 concentration adopted should be consistent with concentrations during
the climatological baseline period.
Conventionally, the baseline CO2 concentration is assumed fixed at a given level. This might be the
reference concentration in which plants have been grown in CO2-enrichment experiments. Alternatively,
it might be the default value assumed in an impact model, usually a value representative of the late 20th
century. However, a word of caution is necessary when testing impact models
for conditions over a 30-year or longer baseline period.
CO2 concentrations have increased rapidly during the 20th century,
and if the exposure unit is responsive to CO2, this temporal trend should be accounted for.
Further information and data relating to CO2 is available
Another gas of importance in some impact studies is tropospheric ozone. This is toxic for a wide range
of living organisms, its concentrations being highly variable in space and time, registering its highest
concentrations over industrial regions under certain weather conditions. Time series of ozone
concentrations are available for some regions, especially in developed countries. They are usually
expressed in terms of background concentrations and peak concentrations. Global model estimates of
ozone abundance and gridded model results are available from the DDC.
Concentrations of stratospheric ozone have been measured operationally at many high latitude sites in
recent years, especially following the discovery of the seasonal "ozone hole" over Antarctica in 1985.
Ozone depletion is associated with increased ultraviolet radiation, which can be harmful for life on
earth. Daily forecasts of exposure risk to UV-radiation are issued in many countries at mid to high
latitudes, especially during the spring and early summer when levels of stratospheric ozone are generally
at a minimum.
Sulphur and nitrogen compounds:
Concentrations of sulphur and nitrogen compounds, which are both major contributors to acid
precipitation in many parts of the world, are also measured in some regions. Furthermore, it has been
estimated that sulphate aerosol concentrations in industrial regions have contributed a cooling effect on
climate in some regions in past decades, which has counteracted the warming effect of greenhouse
Smoke and particulates:
Smoke and other particulate matter in the atmosphere, bi-products of fossil fuel burning, land clearance
or other human activities, can have important regional impacts on visibility and human health. These are
increasingly being observed using satellites as well as ground based instruments.
One of the key factors to evaluate for many impact studies in low lying coastal regions is the current
level of the sea relative to the land. Globally, eustatic sea level (the volume of water in the oceans)
appears to have been rising during the past century. However, there are large
regional deviations in relative sea level from this global trend due to local land movements. Subsidence,
due to tectonic movements, sedimentation, or human extraction of groundwater or oil, enhances relative
sea-level rise. Uplift, due to post glacial isostatic rebound or tectonic processes, reduces or reverses sealevel
rise. The main source of information on relative sea level is tide gauge records, and the major global
data source is the Permanent Service for Mean Sea
As a reference, most studies of vulnerability to sea-level rise use the mean sea-level at a single date. For
instance, studies employing the IPCC Common Methodology use the level in 1990. However, to assess coastal
vulnerability to sea-level effects, baseline tide gauge and wave height observations are required. These
reflect tidal variations in combination with the effects of weather such as severe storms and atmospheric
Inland water levels:
The levels of lakes, rivers and groundwater also vary with time, usually for reasons related to the
natural balance between water inflow (due to precipitation and runoff) and losses (due to evaporation
and seepage). Human intervention can also affect water levels, through flow regulation and
impoundment, land use changes, water abstraction and effluent return and large scale river diversions.
Sometimes these fluctuations in levels can be very large (often much larger than
mean changes anticipated in the future). Thus, where time series are available, it is important to be able
to identify the likely causes of fluctuations (i.e. natural or anthropogenic), as this information could
influence the selection of an appropriate baseline period.
Scenario data the terrestrial environment (land use and land cover - SRES)
Land cover and land use:
On land, data on land cover and land use change are of great importance in many impact studies.
Geographical data and time series have been compiled by a number of research groups working at
national, continental and global scale, based on satellite imagery, aerial photographs and ground survey.
Many datasets have been collected as part of a major international research effort - the
Land Use and Land Cover Change Programme (LUCC)
of the International Geosphere Biosphere Programme (IGBP)
and International Human Dimensions Programme on Global Environmental Change (IHDP). For
instance, a global integrated model,
IMAGE 2, has been used to study the dynamics of land use change.
The model was initialised using baseline land use data from 1970. A continually updated time series of
observed global land use up to the 1990s can then be used to test the model's predictions during the
period after 1970. National land cover/land use statistics have also been tabulated by the IPCC and
are available from the DDC.
Baseline information is also commonly required on the state of the soil where this has been changing
over time, for example, nutrient status, pH and salinity. Data sources for this information tend to be
national or regional in scope.
In agriculture, data on farm management practices are of vital importance in describing the reference
conditions. This covers, for instance, fertilizer applications, use of pesticides and herbicides, tillage
practices, stocking rates and irrigation. Baseline information on these is important, not only because
they have been responsible for dramatic increases in productivity in many regions in recent decades, but
also because they have contributed to soil erosion or pollution of soils, surface waters and groundwater
in many regions. Data for different countries are collected annually by the United Nations Food and Agriculture Organization.
There has been considerable concern in recent years about the endangerment and loss of natural species,
mainly attributable to human activities. There have been a number of national and international
initiatives to document and catalogue biodiversity, and
representative of the 1990s
have been compiled for each country by the World Conservation Monitoring Centre, were published for
an IPCC report on Regional Impacts of Climate Change (available from
Page last modified:
Content last modified: 18 June 2013