Transcript Gillian-Cambers - Regional Policy Briefings

Climate trends, regional and national
climate change projections
Gillian Cambers, SPC, GCCA: PSIS Project Manager
Outline of presentation
• Source of the science presented in this presentation
– the Pacific Climate Change Science Program
(PCCSP)
• Climate change and climate variability
• How has the Pacific climate changed in the last 50
years?
• Changes expected by 2055
• Aid effectiveness and climate change science
1. Source of science presented here
Some of the PCCSP partners from National Meteorological Services
Pacific Climate Change Science Program
The Pacific Climate Change Science Program (PCCSP) is a partnership
between the Australian Government and science agencies (the Bureau of
Meteorology & CSIRO) in close collaboration with 14 Pacific island countries,
East Timor and Pacific regional organisations. The science program is
continuing until 2013 under the banner of PACCSAP.
Goal of the PCCSP
The Pacific Climate Change
Science Program (PCCSP) is
working closely with
National Meteorological
Offices as well as other
national agencies in the 15
partner countries to better
understand how their
climate has changed in the
past and how it may change
in the future.
PCCSP products
• A technical, peer reviewed report Climate
Change in the Pacific: Scientific Assessment
and New Research, launched November 2011:
Volume 1- Regional Overview;
Volume 2- Country Reports
• Eight page brochures on the current
and future climate of each country, English
and local language versions
• All available at:
www.PacificClimateChangeScience.org
2. Climate change and climate variability
Rainfall observations: Niue
Climate variability and change
Climate change
Climate variability
Weather
hours
days
Rain
squall
months
years
centuries
Pacific Decadal
Oscillation (PDO)
Wet season/
dry season
Typhoon
decades
El NiñoSouthern
Oscillation
(ENSO)
Global warming
&
ocean
acidification
Climate change and variability: Tarawa
Climate
Variability
Climate
Change?
3. Pacific climate changes in last 50 years
Changes in the atmosphere
• Air temperatures have warmed across the Pacific
since 1950 between 0.1 – 0.2oC/decade.
• Rainfall across the region has increased and
decreased in response to natural climate variability,
mainly due to the El Niño Southern Oscillation.
• No significant trends in the overall number of
tropical cyclones, or in the number of intense
tropical cyclones in the South Pacific Ocean
between 1981 and 2007.
Changes in the ocean
• Sea-surface temperatures in the region have
generally warmed since 1950.
• Changes in ocean saltiness mirror rainfall changes
• Ocean acidity has increased
• Sea level has risen
Key points
• Analysis of observations show the ocean and
atmosphere have been changing over the past 50 –
60 years
• Considerable variation from country to country
• Climate change signal is very small in comparison to
natural climate variability
• Importance of accurate recording and analysis of
climate observations cannot be over-emphasized
4. Climate projections 2055
Preparation of climate projections
• The climate system is very
complex: we cannot assume
that current trends will continue
• Global climate models; these
are mathematical
representations of the ocean and
atmosphere based on the laws of
physics and run on powerful
computers
• 24 models are available from
around the world
Laws of
physics
Temp, wind,
rain
40 layers
100-400 km
www.pacificclimatefutures.net
Projected climate changes in 21st century
• Increases in air temperature, sea-surface
temperature, extreme rainfall and extreme
temperature events, potential evapotranspiration,
humidity, solar radiation, ocean stratification, sea
level, ocean acidification
• Changes in rainfall, tropical cyclones, wind speed,
salinity
Climate projections 2055
• Regional warming greatest near the equator
• Large increases in extremely hot days and warm
nights
• Increases in annual mean rainfall most prominent
near the SPCZ and ITCZ, little change elsewhere
• More heavy and extreme rain days
• Increases in potential evapotranspiration
• Wind speed generally decreases in the equatorial
and northern parts of the region, while increases are
indicated in the south, but changes are small
• Humidity and solar radiation changes are also small
Projected temperature and rainfall
changes 2055
Greenhouse gas emissions
Northern Marshall Islands
Vanuatu
TEMPERATURE CHANGES RELATIVE TO 1980-2000
Low emissions
0.5 – 1.7
0.5 – 1.5
Medium emissions
0.9 – 2.1
0.8 – 2.0
High emissions
1.0 – 1.8
1.1 – 1.7
RAINFALL CHANGES RELATIVE 1980-2000
Low emissions
-2% to +6%
-11% to +13%
Medium emissions
-7% to +19%
-12% to + 18%
High emissions
-14% to +31%
-10% to +20%
Climate projections - oceans
• Intensified warming and freshening at the ocean
surface is projected to make the surface ocean less
dense compared to the deep ocean, so there is less
vertical mixing
• Regional sea level rise is projected to be similar to the
global average, but improved understanding of the
processes responsible for ice-sheet changes are
needed to improve estimates of the rate and timing
• Higher levels of CO2 will cause further ocean
acidification, increasing risks to reef ecosystems
Ocean acidification
• Ocean acidification is simulated to continue
throughout the 21st century; after 2050, levels of
aragonite saturation in many parts of the Pacific
are projected to fall below 3.5Ω - a critical level for
coral reef health
Tropical cyclones
• South Pacific basin: most models indicate a
decrease in the frequency of tropical cyclones by
2090 and an increase in the proportion of more
intense storms
• North Pacific basin: models indicate a decrease in
the frequency of tropical cyclones and a decrease in
the proportion of more intense storms
Key points
• Climate change and climate variability are already
taking place
• PCCSP’s “Climate Change in the Pacific” and the SPC
book on the “Vulnerability of Pacific fisheries to
climate change” contain rigorous scientific
information on which to base adaptation planning
• Science is continually evolving and climate change
projections are becoming more reliable as our
knowledge grows
Climate science and aid effectiveness
• Do we need more climate science in the Pacific?
• YES
• Building the strength and capacity of national
Meteorological Services to provide the information
on which to base adaptation planning
• Building the capacity of Pacific Island Countries to
adapt to climate change over time frames longer
than the normal project cycle
Thank you