Climate change in the UKOTs an overview of the ... - JNCC - Defra

Box 5. Slow onset versus sudden extreme events
Although there are a range of potential impacts from climate change, ranging from rising
sea levels, to changing rainfall patterns, individuals and countries are likely to experience
climate change in two main ways: either as a change in average climate conditions (often
referred to as slow onset change), or as an increase in sudden, extreme events.
Slow onset changes include:
• Sea-level rise
• Increase in air temperature: The average warming in regions where small islands are
located is likely to be between 2.0°C and 2.8°C by 2050 (compared with 1990
temperatures). By 2080, the increase (above 1990 temperatures) is likely to be
between 3.1°C and 4.3°C.
• Increase in sea surface temperature
• More rainfall and flooding during wet seasons
• Less rainfall during dry seasons.
Examples of sudden, extreme events:
• The frequency of extreme temperatures (e.g., heat waves) is likely to increase
• An increase in the intensity of rainfall
• An increase in the intensity of tropical cyclones.
only things that tell us something is awry
with the global climate.
Changes in climate cues
In some northern latitudes, growing seasons
are longer because spring now
arrives earlier and bird nesting and animal
migration patterns have changed. Some
species of insects, like butterflies, dragonflies
and beetles, are surviving at higher
latitudes than before. Some species more
commonly associated with warmer climates,
like loggerhead turtles, are increasingly
being spotted in the United Kingdom.
Changes in weather patterns
These changes in climate cues are linked
to changes in weather patterns, particularly
changes in temperature and precipitation.
Single abnormalities in weather are
not the things that tell us that climate
change is occurring. On their own, an
unseasonably cool December in Bermuda
Source: Tompkins et al., 2005
or a wetter than usual summer in the
Chagos Islands could be random events,
but evidence of climate change comes
from observed patterns over time. The
IPCC and other climate researchers have
been building a body of observational
data that show medium to long-term
trends, and this information points to four
things.
First, changes in the atmosphere have had
an effect on temperature, precipitation,
storms and sea level. Second, warming
has noticeably influenced many physical
and biological systems (Parry et al., 2007,
Solomon, et al., 2007). Third, climate
change impacts fall into two main categories:
slow onset impacts (changes in
average climate conditions) and extreme
events (increased intensity in rainfall and
tropical storms) (see Box 5). Finally, climate
change is not experienced in the
same way by all countries and regions.
37