Pacific Islands Conference on Climate Change
Rarotonga, Cook Islands 3-7 April 2000
Summary of Day One, 3 April 2000
Session One and Overviews
1. What is our current understanding/capability?
Limited understanding of the Pacific Ocean and its influence on
island climates poor ability to understand rates of change and
magnitude of El Nino to La Nina phases and its impacts on
economic sectors need to increase our ability to use models to
improve the understanding of greenhouse gases (GHG) due to human
activities better information required at regional and national
scales to understand the impacts of climate change Pacific
Island Countries (PIC) understand that climate variability is
the largest climate signal PICs know that their total global GHG
emission (0.3 per cent) is insignificant
2. What do we need to know and do?
Continue to monitor all components of climate systems improve our
scientific tools (meteorological and communications) and networks
(sea level tide gauges) in-situ observations are essential.
Impacts of El Nino and La Nina on economic and environmental
sectors improve the forecast ENSO in the region to Governments
improve the understanding of ocean currents in atoll nations need
better models in the region improve the understanding of climate
change impacts on sea level rise, water, tourism, health, natural
disasters enhance capacity building (human resources and
institutional arrangements) at national level to understand the
science of climate issues e.g. national meteorological services
and water institutions. Contribute to public awareness and
education. Need for better data collection and archiving by
national institutions PICs need to put more effort and resources
to influence UNFCCC/Kyoto Protocol and other related
environmental treaties. Better coordination by SIDS for exchange
of data and information on climate and environment issues.
3. How do we acquire better understanding?
Data exchange to improve our understanding of our regional and
global climate systems international and regional cooperation to
provide a technical and scientific framework for addressing
climate issues at national level.
4. Who should carry out the activities?
Research and monitoring of the science of climate change,
variability and sea level should continue at national, regional
and international levels.
Science Session - Understanding 20th century sea level rise and
future projections
JA Church and J Gregory
Global sea level rise has been 0.5 mm/yr over the last 6000 years
and 0.1-0.2 mm/yr over the last 3000 years. The rate during the
20th century was1-2 mm/yr which is faster observations from
European gauges established an acceleration in relative sea level
rise from 0.4 mm/yr to 0.9 mm/yr per century thermal expansion is
the dominant contribution to sea level rise in the 21st century
according to model results. The rate of temperature rise of about
one degree Celcius is associated with a sea level rise of one
metre per year. Model results also show an acceleration of sea
level rise in the 20th century the terrestrial storage term is
much larger than at first realised.
Projections for 1990 to 2100 total change is 20cm to 70cm using
IS92a GHG emissions scenario for the SRES scenarios it is 10cm to
90cm with a central value of 50cm by 2040 there are virtually no
differences in model results models show significant differences
in the regional distribution of sea level rise leading to poor
confidence there will be a continued thermal expansion for
centuries. It is expected that sea level rise will be one to
three metres over the next 2000 years to reduce uncertainties,
need to re-analyse historical data; analyse satellite data;
better monitor and model ice-sheets; further study terrestrial
storage terms.
Science Session - Climate change in Papua New Guinea
S Maiha
Compiled a database of meteorological observations from 1937 to
the present. Some records held by Australian Bureau of
Meteorology prior to Independence main climate influences are
tropical location; being at heart of Walker Circulation; location
just North of Australia means Southern PNG is influenced
differently; physiography means ranges are aligned NW to SE
whilst the land is aligned W to E longer term datasets are needed
trend in temperature shows a slow increase in line with the
global trend while there has been a decline in rainfall.
Temperature trend agrees with East Asian trend but not Pacific
trend while rainfall trend agrees with Pacific trend but not East
Asian trend
Science Session - Discussions iceberg calving.
Iceberg calving in the Ross Sea was more likely to be natural
process and not due to warming, while calving on the Antarctic
Peninsula may be a result of global warming concerns expressed
from participants for the future of monitoring programmes and the
degradation of networks in the Pacific region. Some long term
records for climate variation studies were held by developed
countries such as New Zealand and these could be released for
study discussion on the implications of sea level rise in the
short to medium term, particularly the influence of El Nino and
La Nina. Response that while human activity is most impacted by
extreme events such as cyclones and storm surges, there are
significant changes in the frequencies of recurrence of these
events with relatively small changes in mean sea levels.
Discussion on the need for high quality in situ monitoring
networks and not just a reliance on remote sensing. PICs are
short of resources to set up and maintain the kinds of networks
needed and would need substantial assistance from donor agencies
Science Session - Satellite altimeter perspective
C LeProvost
Ocean surface variability is found over a range of time and space
scales. Tide gauge networks (such as WOCE/Clivar and GLOSS)
provide limited spatial coverage. The development of satellite
altimetry since the late1980's has enabled excellent spatial
coverage errors in orbit determination reduced from 100cm during
GEOS3 to 3cm for Topex/Poseidon. Improvements in other
corrections now means T/P measures ocean heights to a resolution
of 4cm relative to the reference ellipsoid.
Applications of satellite altimetry the need to correct for tidal
effects resulted in improvements in the knowledge of global
tides. Tides are now known to an accuracy of 2 to 3 cm in the
open ocean and 10-15 cm near coastlines removal of tides and
inverse barometer effect from the signal has enabled computation
of the mean dynamic topography. This has improved our knowledge
of large scale ocean circulation and is also used to monitor sea
level variability. A seasonal cycle in sea level has been
detected which is well correlated with sea surface temperatures
measurements, but lagging by about one month inter-annual
variability can also be monitored. T/P was used to track the
development of the 1997 El Nino and following La Nina event long
term changes in dynamic topography can also be identified, on
both regional and global scales, but care must be taken as the
data span is still quite short in situ gauge networks must be
maintained as an independent observing system which can be used
to check satellite altimeter data. Bias errors in T/P have been
identified from in situ measurements. Differences between T/P and
tide gauge measurements are due to offsets between the sub
satellite point and the tide gauge, which can be corrected for
using models. Trends in these differences are well correlated
with land movements measured by DORIS beacons weekly updates of
ocean sea surface topography are now publicly available which can
be used to monitor the development of meso-scale phenomena such
as El Nino. Future satellite missions (eg Jason and
Doris/ENVISAT), in situ programmes (eg ARGO project) and
collaborative science projects (eg GODAE) are planned to allow
emphasis to be switched to an operational mode in which
predictions can be made.
Science session - J Luick, C Henin
Mechanisms for the 1997 El Nino and following La Nina were
investigated. Data used in these studies included NOAA Analysis
System, T/P sea level data, ERS wind stress and
temperature/salinity current measurements from Wespalis crusies
and ships of opportunity. Wind stress is found to be highly
correlated with sea level at ENSO timescales. Locally forced
Kelvin waves and subsequent Rossby wave solutions are also well
correlated with the observed sea level deformations across the
Pacific. Evidence of algal blooms suggest periods of high
productivity during El Nino.
Science session - Discussion
Concerns were raised that the rise in ocean temperature
associated with La Nina which caused bleaching of coral reefs and
taro field losses were not returning to normal. The question of
forecasts for the Western Pacific was raised. The responses
indicate that ENSO prediction is difficult particularly during
the change in phase between La Nina into El Nino. Seasonal
predictions are available from the CLIP programme of WMO via the
Internet. Two week forecasts are also made from the Pacific
Applications Centre of the U/Hawaii. To prepare for impacts the
question of the influence of anthropogenic effects was raised.
Over the last 20 years there has been high El Nino activity but
low La Nina activity. The influence of decadal oscillations may
be linked to this phenomena, but there is still high uncertainty.
Availability of satellite data to PICs through weekly outputs
from CNES.
Rarotonga, Cook Islands
****************************************************************
To post a submission by email at climate-newswire@sidsnet.org
To unsubscribe, email to majordomo@sidsnet.org with the message:
unsubscribe climate-newswire
To receive updates via email, send an email to majordomo@sidsnet.org with the message:
subscribe climate-newswire
No SUBJECTS required either case.
Brought to you on the SMALL Island Developing States Network: http://www.sidsnet.org
This archive was generated by hypermail 2b29 : Mon Apr 10 2000 - 05:31:03 EDT