Page 36 - index

sPaCe

esa: observiNg

climate chaNge

From space

Satellite observatons of Earth provide essental, objectve informaton on the magnitude and rate of climate
change worldwide. Over the last 40 years this type of data has enabled crucial advances to be made in
understanding the climate system and has been a key component of all fve IPCC assessments.

Today Earth-observing satellites are an are yielding deep insights into the processes systems that governments and businesses
indispensable means of informing and driving climate change. will need to make informed policy, planning
motvatng climate policy decisions. In and investment decisions in the future.
coming decades they will serve both strategic investments
developing and developed natons as a In doing so they are laying the basis for the Space Agencies worldwide are working
practcal tool for planning and assessing improved climate models and predicton together towards the delivery of a global
climate change mitgaton and adapton
actons at local, regional, natonal and
global levels.
Contnuous, long-term, global observaton is Figure 1.
of fundamental importance: Observatons of
declining arctc sea-ice extent made by space-
borne microwave radiometers since the late
1970s have provided defnitve evidence of
on-going change in one of the most sensitve,
but remote parts of the planet.
global eye
Uninterrupted global measurements of the
ocean surface, made by satellite-borne radar
altmeters since 1992, have detected global
average sea-level rise of some 3mm per
year and revealed signifcant (Fig 1) regional
variatons in the rate of change.
Exhaustve analysis of satellite imagery of
more than 170,000 glaciers worldwide,
collected since the 1980s, has delivered the
frst complete global glacier inventory and
documented a patern of systematc retreat.
Policy makers and citzens alike need to be
sure that systems delivering such data are
sustained as operatonal monitoring tools
into the foreseeable future.
Research satellites introducing powerful
new observing technologies are opening a
global view of aspects of climate that were
inadequately understood to date. New
sensors launched during the last fve years
and measuring, for the frst tme, “essental
climate variables” such as sea-ice thickness
(Fig 1), ice sheet elevaton changes, global
soil moisture and ocean salinity from space,

34 www.rtcc.org