Climate change impacts and vulnerability in Europe 2016

Changes in the climate system
climate change through release of CO 2 and CH 4 from
Arctic permafrost areas (Hollesen et al., 2015; Schuur
et al., 2015).
Selection of indicators
The cryosphere provides easily observable signs of
climate change over a wide range of time scales, from
millennia to seasonal variations within a year. This
section presents indicators that cover the following
components of the cryosphere:
• Arctic and Baltic sea ice: sea ice covers large areas. It
reflects light more than open sea and has impacts
on ocean circulation, which transports heat from
the equator to the poles. Sea ice and its variations
also affect navigation and the exploitation of natural
resources.
• Greenland and Antarctic ice sheets: the continental ice
sheets of Greenland and the Antarctic influence the
global climate in many ways. First of all, they have
important effects on global sea level. Furthermore,
they modify ocean temperatures and circulation,
vegetation and land-surface albedo.
• Glaciers: glaciers and ice caps influence sea level, river
flow and freshwater supply, ecosystems and many
human activities.
• Snow cover: snow covers a large area, but has a
relatively small volume. Its reflection of light is
important for climatic conditions, it insulates the soil
in winter and is an important source of temporary
water storage.
Information on changes in permafrost is not presented
as an indicator. In the past 15–25 years for which
data are available, European permafrost has shown a
general warming trend, and the depth of seasonal thaw
has increased at several European permafrost sites
(Harris et al., 2009; EEA, 2012). Substantial near-surface
permafrost degradation is projected over much of the
permafrost area, which is expected to increase the
risk of rock falls, debris flows, ground subsidence and
impacts on biodiversity (Shaefer et al., 2012). Efforts to
improve and systematise the monitoring of permafrost
are being pursued (Biskaborn et al., 2015).
Data quality and data needs
Data on the cryosphere vary significantly with regard
to availability and quality. Snow and ice cover have
been monitored globally since satellite measurements
started in the 1970s. Improved technology allows
for more detailed observations and observations
of a higher resolution. High-quality long-term data
are also available on glaciers throughout Europe.
Direct historical area-wide data on the Greenland
and Antarctic ice sheets cover about 20 years, but
reconstructions give a 200 000-year perspective.
Continuous efforts are being made to improve
knowledge of the cryosphere. Scenarios for the future
development of key components of the cryosphere
have recently become available from the CMIP5 project,
which has provided climate change projections for the
IPCC AR5 (see Section 3.1). Owing to their economic
importance, considerable efforts have also been
devoted to improving real-time monitoring of snow
cover and sea ice.
Climate change, impacts and vulnerability in Europe 2016 | An indicator-based report
91