Climate change impacts and vulnerability in Europe 2016

Changes in the climate system
3.2 Atmosphere
Key messages
• Three different long-term observational records show that the global average annual near-surface (land and ocean)
temperature in the decade 2006–2015 was 0.83 to 0.89 °C higher than the pre-industrial average. The year 2015 was the
warmest on record globally, at approximately 1 °C above the pre-industrial level.
• European land areas in the decade between 2006 and 2015 have warmed by around 1.5 °C since the pre-industrial age.
The years 2014 and 2015 were jointly the warmest years on record in Europe.
• Further global warming between 0.3 and 4.8 °C is projected for the 21st century, depending on the emissions scenario.
The annual average land temperature across Europe is projected to continue increasing faster than global average
temperature.
• Since 2003, Europe has experienced several extreme summer heat waves (2003, 2006, 2007, 2010, 2014 and 2015).
Such heat waves are projected to occur as often as every two years in the second half of the 21st century under a high
emissions scenario (RCP8.5). The impacts will be particularly strong in southern Europe.
• Precipitation changes across Europe show more spatial and temporal variability than temperature changes. Annual
precipitation has increased in most of northern Europe, in particular in winter, and has decreased in most of southern
Europe, in particular in summer. Heavy precipitation events have increased in northern and north-eastern Europe since
the 1960s whereas different indices show diverging trends for south-western and southern Europe. Heavy precipitation
events are projected to become more frequent in most parts of Europe.
• Observations of wind storm location, frequency and intensity have shown considerable variability across Europe during
the 20th century. However, most studies agree that the risk of severe winter storms, and possibly of severe autumn
storms will increase in the future for the North Atlantic, as well as for northern, north-western and central Europe.
• Hail is responsible for significant damage to crops, vehicles, buildings and other infrastructure. Despite improvements
in data availability, trends and projections of hail events are still subject to large uncertainties owing to a lack of direct
observation and inadequate microphysical schemes in numerical weather prediction and climate models.
3.2.1 Overview
Relevance
Changes in atmospheric composition affect
atmospheric climate variables, in particular
temperature, precipitation and wind speed, which in
turn affect almost all natural and human-managed
systems, as well as human health and well-being.
In fact, climate change is often equated with
atmospheric changes, and changes in other climate
system components, such as the hydrosphere and
the cryosphere, are often considered effects of
atmospheric changes. It is therefore not surprising
that global mean surface temperature is specifically
mentioned as a proxy for the magnitude of global
climate change in Article 2 of the UNFCCC (UN, 1992),
and that the political discussion on global climate
policy often focuses on the most appropriate value
for constraining its increase (see Chapter 2 for further
details).
While changes in annual or seasonal averages of
atmospheric climate variables are easier to monitor
and report, changes in extreme weather events
(e.g. heat waves, heavy precipitation, wind storms and
hail), which generally have the highest impact and
cause the greatest damage to humans and natural
systems, are more difficult to detect.
Selection of indicators
The following are six indicators that describe past
trends and projected changes in the most dynamic
component of the Earth's climate system: the
atmosphere.
• Global and European temperature consists of two
parts. Global mean surface temperature is the key
climate variable to track anthropogenic climate
change. It is also the only climate variable for which
a political target exists. The average European land
temperature gives a clear signal of climate change
Climate change, impacts and vulnerability in Europe 2016 | An indicator-based report
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