Syntheserapport project Klimaatdienstverlening: Klimaatdienstverlening: Maatwerk

This report summarizes the results of the project “Tailoring climate scenarios” (project CS7) of the
Climate changes Spatial Planning programme. In 2005 KNMI started this project in cooperation
with several users to provide them with climate information tailored to their requirements. One
part of the project focussed on communication: among others which climate data do users need
and why, giving presentations, development of a website on the KNMI’06 climate scenarios. The
other part of the project dealt with the development of methods to tailor climate information. This
was done within six pilot projects.
In Chapter 2 specific aspects of tailoring – e.g. how to find out which data users really need, how to
deal with uncertainties – are presented with the help of four examples of tailoring projects. These
four projects differ in scale (national to local) and sector (spatial planning, water management and
energy). The results and insights from the whole CS7 project are summarized in Chapter 3.
Tailoring requires continuous communication adjusted to the various users
Tailoring climate information is not as simple as “you ask we deliver”, however is requires continuous
contact with users of climate information. To deliver relevant climate information in the right format
it is important to know who will be using the climate information and data, how it will be used and
why they use it. Organising meetings with climate researchers and users of climate information
together, and working together in projects resulted in mutual understanding on the requirements of
users and the limitations to deliver certain types of climate information. This mutual understanding
facilitates the communication and results in more widely accepted products.
Uncertainties
The knowledge of users on uncertainties in climate and climate change projections varies
enormously. Different groups also have different ways of dealing with uncertainties. Therefore, a
lot of attention is paid to communication on uncertainties in tailoring projects. On internet and in
reports descriptions and examples are given of the various types of uncertainties in climate data
and climate information. Much attention is given also to how to use scenarios and how to present
results: e.g. always present pictures of at least 2 climate scenarios to make the users and public
aware of the uncertainties about our future climate.
Methods to tailor climate information are an extra source of uncertainty
Available information on the current and future climate can not be used always directly in climate
impact studies – observational time series are sometimes too short, or information on percentages
change in the KNMI’06 climate scenarios are not sufficient. For processing climate information
several methods are developed in this project. An overview of methods for the current and future
climate is given in Tables 3.1 and 3.2. It is also indicated in which project which method is used. The
key element in these methods is the generation of time series, which can often be used directly
in impact models or can be used to derive climate indices. Time series of climate variables for the
future can be generated with different methods, each with its own advantages and limitations.
A few of the tailoring projects show that the use of one method or another can lead to different
estimations of the impacts of climate change. Therefore, the tailoring methods themselves can be
an extra source of uncertainties.